NanoPT2015

L e a d O r g a n i s e r

September 07-11, 2015

www.tntconf.org/2015

The 16th edition of the Trends in Nanotechnology

International Conference (TNT2015) is being

launched following the overwhelming success of

earlier Nanotechnology Conferences.

Index

Foreword / Organisers Page 5

Sponsors/Committees Page 6

Exhibitors Page 7

Speakers Page 12

Abstracts Page 17

Posters List Page 109

n a n o P T 2 0 1 5 P o r t o ( P o r t u g a l ) | 5

Foreword

We take great pleasure in welcoming you to Porto (Portugal) for the 3

rd edition of the nanoPT

International Conference (nanoPT2015).

The third edition will be held with the purpose of strengthen ties nationally and internationally on

Nanotechnology and, pretends to be a reference in Portugal in the upcoming years. This conference will

encourage industry and universities working on the Nanotechnology field to know each other and to

present their research, allowing new collaborations between nearby countries such as Spain and France.

nanoPT 2015 will let participants to present a broad range of current research in Nanoscience &

Nanotechnology, not only the most prominent investigations/studies in Portugal but from all over the

World.

We are indebted to the following Institutions for their financial support: American Elements, International

Iberian Nanotechnology Laboratory (INL) and FEI.

We would also like to thank the following companies and institutions for their participation: Raith GmbH,

Kurt J. Lesker, SOQUIMICA, Fritsch, BIOPTICA, Oerlikon Leybold Vacuum, NT-MDT, CRESTEC Corporation

and ScienTec Ibérica.

In addition, thanks must be given to the staff of all the organising institutions whose hard work has helped

planning this conference.

Organisers

6 ||||

Sponsors

Committees

|||| n a n o P T 2 0 1 5

Sponsors

Committees

O r g a n i z i n g C o m m i t t e e

Antonio Correia

Braz Costa

Lars Montelius

Jose Rivas

Vasco Teixeira

S c i e n t i f i c C o m m i t t e e

Jean

Stephan Roche

Juan José Sá

T e c h n i c a l C o m m i t t e e

Viviana Estêvão

Jose Luis Roldán

n a n o P T 2 0 1 5

Sponsors

Committees


Antonio Correia

Braz Costa

Lars Montelius

Jose Rivas

Vasco Teixeira


Jean-Pierre Aimé

Stephan Roche

Juan José Sá


Viviana Estêvão

Jose Luis Roldán

n a n o P T 2 0 1 5

Sponsors

Committees


Antonio Correia

Braz Costa

Lars Montelius

Jose Rivas Santiago de Compostela Univ. (Spain)

Vasco Teixeira


Pierre Aimé

Stephan Roche

Juan José Sá


Viviana Estêvão

Jose Luis Roldán

n a n o P T 2 0 1 5

Sponsors

Committees


Antonio Correia

Braz Costa CITEVE/CENTI

Lars Montelius INL (Portugal)

Santiago de Compostela Univ. (Spain)

Vasco Teixeira Univ.


Pierre Aimé

Stephan Roche ICN2 (Spain)

Juan José Sáenz


Viviana Estêvão

Jose Luis Roldán

n a n o P T 2 0 1 5 P o r t o ( P o r t u g a l )

Sponsors

Committees


Phantoms F

CITEVE/CENTI

INL (Portugal)


Univ. Minho (Portugal)


Pierre Aimé UMR 5248 CBMN CNRS

ICN2 (Spain)

UAM


Viviana Estêvão Phantoms F

Jose Luis Roldán Phantoms F

P o r t o ( P o r t u g a l )

Committees


Phantoms F

CITEVE/CENTI (Portugal

INL (Portugal)


Minho (Portugal)


UMR 5248 CBMN CNRS

ICN2 (Spain)

AM (Spain


Phantoms F

Phantoms F


Committees


Phantoms Foundation (Spain)

(Portugal

INL (Portugal)


Minho (Portugal)


UMR 5248 CBMN CNRS

ICN2 (Spain)

Spain)






undation (Spain)

(Portugal)


Minho (Portugal)


UMR 5248 CBMN CNRS


undation (Spain)

undation (Spain)



undation (Spain)


Minho (Portugal)

UMR 5248 CBMN CNRS -

undation (Spain)

undation (Spain)


undation (Spain)


Universite Bordeaux (France)

undation (Spain)

undation (Spain)


Universite Bordeaux (France)

Universite Bordeaux (France)Universite Bordeaux (France)Universite Bordeaux (France)Universite Bordeaux (France)

n a n o P T 2 0 1 5 P o r t o ( P o r t u g a l ) |||| 7

Exhibi tors

S O Q U I M I C A

Since 1929, SOQUIMICA commercializes high quality laboratory equipment and provides highly

specialized services to its customers.

We offer our clients the expertise of a qualified and experienced team, which enables support for

the development of tailor-made solutions.

The equipment we sell and the services we provide allow our customers to enjoy the best

solutions for various Applications (Chemical analyzes, Gas and liquid chromatography,

Spectroscopy, Genomics, Life sciences, Laboratory Weighing, Industrial Weighing, Preparation of

samples) and Industries (Environment, Forensics and Toxicology, Energy & Chemicals, Food

Industry and Agriculture, Pharmaceuticals and Biotechnology Industry, Textile Industry,

Inspection of products and materials testing, Clinical research, Refinery & Petrochemicals).

www.soquimica.pt

8 |||| n a n o P T 2 0 1 5 P o r t o ( P o r t u g a l )

O e r l i k o n L e y b o l d V a c u u m

Oerlikon is a worldwide leading high-tech industrial group, specialized in mechanical and

industrial engineering. Oerlikon Leybold Vacuum is the vacuum part of the Oerlikon Group. We

offer a wide range of advanced vacuum solutions for research purposes and analytical processes,

as well as for manufacturing processes. The company's core capabilities center on the

development of application and customer specific systems for the creation of vacuum and

extraction of process gases. Oerlikon Leybold Vacuum's ability to meet highest requirements of

most complex applications gives our customers the competitive edge to succeed. High duty

processes in metallurgy, clean-room conditions at worldwide renowned institutes for research

and development, or coating applications of minute dimensions – Oerlikon Leybold Vacuum

offers highest performance. In Spain the daughter company was established in 1964, being

currently responsible for Spain and Portugal.

www.oerlikon.com/leyboldvacuum/spain/es

R a i t h

Raith offers innovative solutions for sub-10nm focused ion beam (FIB) nanofabrication, SEM-

based electron beam lithography (EBL), large area SEM image capture, gas-assisted

nanolithography, in situ nanomanipluation and nanoprofilometry. Raith’s proprietary FIB

technology offers a wide range of ion species and elevates FIB based nanofabrication to a new

level with highest selectivity and unsurpassed stability for automated wafer-scale patterning.

nanoPT2015

Contact: Mr. Vincent Morin

Raith GmbH

Konrad-Adenauer-Allee 8

44263 Dortmund / Germany www.raith.com

[email protected]


C r e s t e c C o r p o r a t i o n

CRESTEC is a worldwide Electron Beam Lithography system manufacturer. We are going to

present our new product CABL-UH series which is equipped with the world the highest

acceleration voltage 130kV this time. The existing Electron Beam Lithography system series

CABL-9000C will be displayed and its upgraded basic performances and writing capabilities will

be described by display panels. We are offering sample fabrication services suitable for

customers needs.

Contact:

Crestec Corporation

1-9-2 Owada-machi, Hachioji-shi, Tokyo, 192-0045 Japan

+81-42-660-1190 [email protected]

www.crestec8.co.jp

B i ó p t i c a

For more than 20 years Bióptica, LDA works with Horiba Scientific, a global leader in fluorescence

and Raman spectroscopy. Horiba Scientific has a full range of solutions in the nano-spectroscopy

field: AFM-Raman, TERS, NSOM, chemical imaging at the nanoscale, nanofluorescence/TCSPC

and ellipsometry.

Bioptica, LDA also commercializes:

− Continuum/Amplitude Systèmes;

− Laser Quantum/Venteon;

− CVI Melles Griot;

− A complete light measurements solutions from the leading company Instrument

Systems, GmbH;

− Cytoviva Hyperspectral Imaging technology designed to provide spectral

characterization and mapping of nano-materials.”

www.bioptica.pt


N T - M D T

From cutting edge scientific research to routine surface investigations, NT-MDT has a unique and

unrivalled portfolio of scanning probe microscopes. Our application-focused instruments provide

you with a full range of capabilities in AFM-Raman, high-resolution, multi-frequency

measurements, and AFM based nanomechanics. As an innovator in SPM for over 20 years, NT-

MDT has a specialized high-performance solution for your research needs.

Key Products: SPM/AFM/STM; Raman TERS; Spectroscopy

[email protected] www.ntmdt.us

S c i e n T e c I b é r i c a

ScienTec Ibérica, is the spanish branch of ScienTec France, its mission is to serve and attend

the Iberian Nano-micro surface analysis market from its office in Madrid. Its field of activity is

related to scientific research, R&D and industrial metrology. In terms of product line, we deal

with atomic force microscopes, contact profilometry, digital holography, interferometry,

nanoindentation, filmetrics and high aspect ratio confocals. Recently we have expanded our

portfolio to customized UltraHigh Vacuum Systems, XPS;ESCA… ScienTec Ibérica accompanies

you in your various projects by offering system adapted to your applications (nanotechnology,

polymer, material surfaces, biology, semiconductor, microfabricaiton and the cutting tool

industry…).

www.scientec.es

K u r t J . L e s k e r C o m p a n y

As a leading global provider of high-quality vacuum products and systems, along with an

established tradition of service and attention to detail, the Kurt J. Lesker Company® (KJLC®) has

built a reputation for “Enabling Technology for a Better World”.

The common attribute across the entire company is the relentless and tireless pursuit of quality

and customer satisfaction, both in the vacuum products and the services we provide worldwide.

KJLC takes this responsibility seriously, working at all levels to ensure high quality performance in

all our products.

www.lesker.com

Speakers


Index alphabetical order

K: Keynote Speakers

O: Orals (Plenary Session)

OP: Orals (Parallel Session)

Speakers

Page

Al-Mutairi, Eid (Chemical Engineering Department, Saudi Arabia)

“Design and Optimization of CNTs Production in Chemical Vapor Deposition Reactor” OP 19 Andrade, Suzana M. (Instituto Superior Técnico - Centro de Química Estrutural, Portugal)

“Toward multifunctional gold nanoparticles/graphene hybrid assemblies associated to

photoactive molecules” O 20 Araújo, José (REQUIMTE / University of Porto, Portugal)

“Surpassing NSAIDs side-effects with Lipid Nanoparticles” OP 22 Artacho, Emilio (CIC nanoGUNE, Spain)

“On the origin and switching of a two -dimensional electron gas under a thin perovskite film” K 23 Bagaturyants, Alexander (Photochemistry Center RAS, Russia)

“Multiscale Atomistic Modeling of Amorphous Organic Functional Materials for Optical

Chemical Sensing and OLED Applications” O 25 Bettencourt, Ana (Universidade de Lisboa, Portugal)

“Does surface charge play a role in nanoparticulate-systems toxicity?” O 27 Bonaccorso, Francesco (IIT, Italy)

“Solution processing of grapheme, related 2d crystals and hybrid structures for energy

conversion and storage” K 29 Borme, Jerome (INL - International Iberian Nanotechnology Laboratory, Portugal)

“Wafer-scale fabrication of solution-gated graphene field-effect transistors for biosensing

applications” O 30 Carrola, Joana (University of Aveiro, Portugal)

“Metabolic effects of silver nanoparticles assessed by NMR metabolomics of mice liver and

serum” OP 32 Carvalho, Filomena (Instituto de Medicina Molecular, Portugal)

“AFM as a nanotool to evaluate protein-cell interactions and cell-cell adhesion on

cardiovascular pathologies” O 34 Costa, José Diogo (International Iberian Nanotechnology Laboratory (INL), Portugal)

“Nanofabrication of Magnetic Tunnel Junction Pillars Targeting Nano-Oscillator Applications” OP 36 Costa, Pedro (Physical Sciences and Engineering Division, Saudi Arabia)

“The structure and chemistry of CNTs in electrical nanodevices fabricated by beam

deposition” O 38 Cruz, Fernando (Requimte/CQFB, Universidade Nova de Lisboa, Portugal)

“Thermodynamics of DNA Strands Encapsulated into Electrically Charged Nanotubes” O 39 Cunha, Eunice (Instituto de Polímeros e Compósitos, Portugal)

“Exfoliation of graphite using pyrene and perylene derivatives” OP 41 Ferreira, Mauro (Trinity College Dublin, Ireland)

“Sublattice asymmetry of substitutionally doped impurities in graphene” O 43 Ferreira, Quirina (Instituto de Telecomunicações, Portugal)

“Biocompatible and nanostructured monolayers on graphite for drug delivery applications” O 44 Figueiras, Fábio Gabriel (IFIMUP-IN Univ. Porto & CICECO Univ. Aveiro, Portugal)

“Nanometric Bias Induced Phase Transitions in materials” O 45

14 | n a n o P T 2 0 1 5 P o r t o ( P o r t u g a l )

Page

Fortunato, Elvira (CENIMAT-I3N , Portugal)

“A review on metal oxide semiconductors applied to transistors: from nanofilms to nanoparticles” K 46 Freidzon, Alexandra (Photochemistry Center, Russian Academy of Sciences, Russia)

“Spectral and Transport Parameters of Electron-Transporting Materials

Bis(10-hydroxybenzo[h] qinolinato) beryllium (Bebq2)” OP 47 Frias, Iúri (REQUIMTE / University of Porto, Portugal)

“Development of lipid nanocarriers-based epigallocatechin gallate for preventive and

therapeutic supplementation” OP 48 Fu, Guodong (Southeast University, China)

“Preparation of Fluorescent Organometallic Porphyrin Complex Nanogels” O 49 Gaspar, André (Universidade de Coimbra, Portugal)

“Development of a biodegradable magnetic nanoprobe using SPIONs and Amazonian

essential oils” OP 50 Gaspar, Vitor (CICS-UBI - Health Sciences Research Centre, Portugal)

“Simultaneous Delivery of Drugs and Genes by Multi-block Polymeric Nanomicelles for

Synergistic Cancer Therapy” OP 52 Gnilitskyi, Iaroslav (University of Modena and Reggio Emilia, Italy)

“Strongly anisotropic wetting on highly-uniform self-similar molybdenum nanogrooves” OP 53 Gomes, João (CENTI, Portugal)

“Optimization of processing and encapsulation conditions of white OLED devices for

decorative lighting applications” K 55 Gouveia, Virgínia (REQUIMTE / University of Porto, Portugal)

“pH sensitive liposomes loading prednisolone for the treatment of rheumatoid arthritis” OP 56 Ilyas, Muhammad (Brunel University London, United Kingdom)

“Use of Nano-Technology and Nanomaterial in the Development of Nanocomposite

Cementitious Materials” OP 57 Kolen'ko, Yury V. (International Iberian Nanotechnology Laboratory (INL), Portugal)

“p-Type Cu2O colloids optimized for photoelectrochemistry and electronics” O 59 Kuzmenko, Igor (Ben Gurion University of Negev, Israel)

“Two-Channel Kondo Effect in Carbon Nanotube Quantum Dot” O 60 Lee, Seunghwan (Technical University of Denmark, Denmark)

“Mucoadhesion to Improve Slipperiness of Mucin Layers” O 62 Lima, Sofia (REQUIMTE / University of Porto, Portugal)

“Temperature-responsive polymeric nanospheres containing methotrexate and gold

nanoparticles: a multi-drug system for theranostics in rheumatoid arthritis” O 64 Liu, Lifeng (INL, Portugal)

“Extraordinarily Efficient Electrocatalytic Hydrogen Evolution Achieved by Amorphous

MoOxSy Catalysts Electrodeposited on Crystalline TiO2 Nanotube Arrays” O 66 Martinsone, Zanna (Rigas Stradins University, Latvia)

“Instrumentation for qualifying and quantifying nanoparticles’ exposure into occupational

environment” OP 67 May, Mousa (Sebha University, Libya)

“Effects of γ-Al2O3 nanoparticles on the adhesive strength of composite epoxy/sol-gel materials” OP 69 Merkoçi, Arben (ICN2, Spain)

“Nanobiosensors and applications in diagnostics” K 70 Mohseni, Farzin (Universidade de Aveiro, Portugal)

“Magnetic and morphologic properties of Alnico-based rare-earth free permanent magnets” OP 71 Montelius, Lars (INL - International Iberian Nanotechnology Laboratory, Portugal)

“Bridging the materials gap through radical Innovations” K 73


Page

Moreira Pinto, Artur (LEPABE, Portugal)

“Effect of biodegradation on PLA/graphene-nanoplatelets composites mechanical

properties and biocompatibility” OP 74 Morin, Vincent (Raith GmbH, Germany)

“Ion Column and Source technology employing Gallium and New Ion Species for Advanced

FIB Nanofabrication” O 76 Neves, Ana (University of Exeter, United Kingdom)

“Graphene-coated transparent conducting fibres for smart textiles” O 78 Nieder, Jana Berit (INL-International Iberian Nanotechnology Laboratory, Portugal)

“Presentation of the New “Ultrafast Bio-and Nanophotonics” Laboratory at INL” OP 79 Onida, Giovanni (Istituto Nazionale di Fisica Nucleare (INFN), Italy)

“Carbon sp wires and their coupling to graphene” O 80 Pereira, Maria (Universidade de Aveiro, Portugal)

“Scanning Thermal Microscopy: unraveling and mapping thermal phenomena at the nanoscale” OP 81 Peressi, Maria (University of Trieste, Italy)

“Seeding, nucleation and reactivity of alumina/Ni3Al(111)supported metallic nanoclusters:

an ab-initio investigation” O 83 Perez Roldan, Maria Jesus (CIC nanoGUNE Consolider/Advanced microscopy, Spain)

“One step FEBID fabrication of Co based magnetic nanotubes” O 84 Pinto, Inês (INL - International Iberian Nanotechnology Laboratory, Portugal)

“Epithelial Tumor Dynamics: Nanocharacterization of force-generating structures” K 108 Queiroz, Joana (REQUIMTE / University of Porto, Portugal)

“New insights in the development of solid lipid nanoparticles for active brain-targeted

drug delivery” O 85 Rana, Sohel (University of Minho, Portugal)

“Development of Ductile Cementitious Composites Using Carbon Nanotubes” O 86 Raposo, Claudia (IBET, Portugal)

“Synthesis of novel galactose-PLGA nanoparticles containing doxorubicin for hepatocyte

targeting” O 88 Repetto, Diego (University of Genoa, Italy)

“Transparent aluminum nanowires electrodes with optical and electrical anisotropic

response fabricated by defocused ion beam sputtering” O 89 Ribeiro, Daniela (ICETA/REQUIMTE/FFUP, Portugal)

“Characterization of Model Membranes under the Effect of Anticancer Drugs” O 90 Rios, Angel (University of Castilla-La Mancha, Spain)

“New approaches in the development of analytical methodologies involving the use of

CdSe/ZnS quantum dots” O 91 Rosário, Carlos (Universidade de Aveiro, Portugal)

“Resistive switching and impedance spectroscopy in metal-oxide-metal trilayers with SiOx

and ZrO2: a comparative study” OP 93 Seah, Choon Ming (Institut Jean Lamour, CNRS-Université de Lorraine, France)

“An Improved Wet Chemical Approach For The Separation Of Graphene From Nickel Foil

ToThe Reutilization Of Catalyst” OP 95 Serrano Núñez, Juan Manuel (Sesderma, Spain)

“Repair of UV light-induced dna damage” OP 96 Silveirinha, Mario (Universidade de Coimbra, Portugal)

“Taming light at the nanoscale with metamaterials” K 98 Soto Beobide, Amaia (Foundation for Research&Technology-Hellas– Institute of Chemical

Engineering Sciences, Greece)

“Carbon Nanotube reinforced Textiles for Civil Protection Services” OP 99


Page

Tarequzzaman, Mohammad (International Iberian Nanotechnology Laboratory, Portugal)

“Large power emission in MTJ based spin torque nano-oscillators using a free layer near

the in-plane to out-of plane transition” OP 101 Vila, Ana (International Iberian Nanotechnology Laboratory (INL), Portugal)

“Designed Nanocomposite Magnetic Beads for isolation of Circulating Tumor Cells (CTC)” O 103 Vila, Mercedes (University of Aveiro , Portugal)

“Nanographene Oxide mediated cell hyperthermia” K 104 Wang, Xiaoguang (International Iberian Nanotechnology Laboratory (INL), Portugal)

“Direct Growth of Nickel Phosphoride Nanoneedles on Nickel Foam for Efficient

Electrocatalytic Hydrogen Evolution” OP 105 Yerchuck, Dmitri (Heat-Mass Transfer Institute of National Academy of Sciences of RB, Belarus)

“New Quantum Physics Phenomena in Optical and Radio Spectroscopies” OP 107

Abstracts


Eid M. Al-Mutairi

Chemical Engineering Department ,

King Fahd University of Petroleum & Minerals,

Dhahran 31261, Saudi Arabia

D e s i g n a n d O p t i m i z a t i o n o f

C N T s P r o d u c t i o n i n C h e m i c a l

V a p o r D e p o s i t i o n R e a c t o r

The Chemical Vapor Deposition (CVD) parameters

were studied to selectively synthesize Carbon Nano

Tubes (CNT’s). Experimental runs using Vertical

Chemical Vapor Deposition (CVD) reactor were

performed at a fixed reaction time of one hour and

different operating temperatures (700-1000 Co),

hydrogen flow rates (100-3000 mL/mint) and P-

xylene flow rates (5-40 mL/hr). Ferrocene [Fe

(C5H5)2] catalyst was used in the process in the form

of powder which is mixed and dissolved with P-

xylene (C8H10) at a ratio of 1% of Fe (50 mL solvent,

1.6 g Ferrocene) to the hydrocarbon. The P-xylene

as the source of the hydrocarbon was cracked by

hydrogen while argon gas was used to flush the CVD

reactor to prevent oxidation of the catalytic metal at

the reaction temperatures. Effects of the various

operating parameters on the yield and quality of

CNT’s such as temperature and the flow rates of

hydrocarbon and hydrogen are presented in this

study. The effects of the different reaction

conditions on the CNT’s yield and various

dimensions of the CNTs formed were also

investigated. A design of experiment package was

used for the generation and evaluation of statistical

experimental designs. A 3k statistical factorial design

approach was adopted to develop the mathematical

models in order to study and optimize the operating

conditions.Multiple Linear Regression (MLR) was

used to fit the mathematical models. The

morphologies of the CNTs were characterized and

examined by Scanning Electron Microscopy (SEM) at

different growth temperatures for the surface

morphology of the samples and Thermal Gravity

Analyzer (TGA) was used to analyze purity of CNT’s.

A design of experiment optimizer was used to find

the optimum conditions for the yield and quality of

CNT’s where optimum yield was found to be at a

temperature of 892 Co and H2 flow rate of 1497

mL/mint with P-xylene rate of 5 mL/hr. However, to

control quality, higher H2 flow rate (3000 mL/mint)

need to be considered to improve average

diameters and aspect ratios of the produced CNT’s.


Suzana M. Andrade1, C.J. Bueno-

Alejo1, V. Vaz Serra

1,2, S.M.B.

Costa1, P. Serp

3

1Centro de Química Estrutural, Instituto Superior

Técnico, Universidade de Lisboa-Portugal 2Departamento de Química & QOPNA,

Universidade de Aveiro- Portugal 3Laboratoire de Chimie de Coordination UPR CNRS,

composante ENSIACET, Toulouse University – France

[email protected]

T o w a r d m u l t i f u n c t i o n a l g o l d

n a n o p a r t i c l e s / g r a p h e n e

h y b r i d a s s e m b l i e s a s s o c i a t e d

t o p h o t o a c t i v e m o l e c u l e s

Light-induced doping with excited-state electron

donors or electron acceptors is a versatile strategy

for the fabrication of photoactive carbon-based

nanocomposites (CBN).

Important contributions stem from π−π interactions

with amphiphilic porphyrinoids. Depending on the

architecture organization, photophysical studies

showed strong electronic communications between

the chromophoric moieties and carbon nanotubes [1].

Gold nanoparticles (AuNP) are one of the most

interesting nanostructures. Among their excellent

properties, the presence of a surface plasmon band

in the visible region of the electromagnetic

spectrum makes these materials suitable for many

attractive applications in fields such as medicine,

sensors, and catalysis. For these applications, an

optimization of the gold particle size, the

distribution of particle sizes and their dispersion on

the graphene surface is desirable.

With this in mind, we have prepared AuNP

supported by different CBN: graphene oxide (GO),

N-doped graphene (N-G) and soft functionalized

graphene (fG). The AuNP were supported in two

different ways: a) by a modification of the literature

sonolytic method,[2] which consists in the

sonication of the support and the Au salt in aqueous

suspensions; b ) by the simple mixing of pre-

synthesized AuNP with the support. The morphology

and size distribution of the nanoparticles within the

supports were studied by AFM and TEM. N-G was

found to have a strong influence on the particle

density and size distribution (Figure 1). Very fine

particles in the size range of 1-3 nm were observed

even though some particles were much bigger in

size even up to 20 nm.

The covalent and non-covalent interactions of these

hybrid materials with porphyrinoids (Por, Figure 2)

was subsequently investigated using both steady-

state and time-resolved fluorescence, including FLIM

microscopy. The luminescence quenching observed

(Figure 3) is tentatively assigned to a competition

between two possible processes: photoinduced

electron transfer and energy transfer. However, in

the presence of CBN-AuNP composites there is an

enhancement of the porphyrinoid fluorescence

involving a surface plasmon coupling effect. These

new nanostructures are thus expected to have

selective photocatalytic and sensing abilities.

R e f e r e n c e s

[1] S.M. Andrade, P. Raja, V.K. Saini, A.S. Viana, P.

Serp, S.M.B. Costa, ChemPhysChem 13 (2012)

3622-3631.

[2] K. Vinodgopal, B. Neppolian, I.V. Lightcap, F.

Grieser, M. Ashokkumar, P.V. Kamat, J. Phys.

Chem. Lett. 1 (2010) 1987–1993.

A c k n o w l e d g e m e n t s :

Project PTDC/Qui-Qui/117498/2010 funded by FCT

is acknowledged.


F i g u r e s

Figure 1: TEM images showing (a) GO, and AuNP anchored on (b) GO; (c) N-G and (d) fG (right) sheets, prepared using a modified sonolysis method.

Figure 2: Porphyrinoids used in this study: meta-

methoxy-phenyl porphyrin monosubstituted with a

polylysine chain (MMA-PLL, left) and tetrasulfonated

aluminium phthalocyanine (AlPcS4, right).

Figure 3: Left: Fluorescence spectra of Por/GO and Por/Au@GO (MMA-PLL, blue; AlPcS4, green); Center: FLIM images of MMA-PLL (top) and AlPcS4

(bottom) in the presence of GO; and Right: Fluorescence lifetime distributions of MMA-PLL (top) and AlPcS4 (bottom) alone and in the presence of

Au@GO.).


Araújo J., Neves, A. R., Gouveia, V.,

Moura, C., Nunes, C. and Reis, S.

REQUIMTE, Departamento de Química, Faculdade

de Farmácia, Universidade do Porto, Porto,

Portugal

[email protected]

S u r p a s s i n g N S A I D s s i d e -

e f f e c t s w i t h L i p i d

N a n o p a r t i c l e s

The inflammatory process is the innate immune

response for the presence of pathogens, toxic

molecules, tissue injuries or any other harmful

conditions. The inflammation process is

characterized for redness, pain, swelling, heat and

disturbance of function and comprises inducers,

sensors, mediators and effectors components from

cellular and humoral origin. Macrophages are one

of the most important cells in the inflammatory

process. Macrophages actively phagocyte particles

with sizes superiors to 200 nm and express folate

receptor making them of great interest for passive

and active targeting strategies. Non-Steroidal Anti-

Inflammatory Drugs, like oxaprozin, are one of the

most used drugs prescribed for these conditions,

however these drugs have adverse side effects,

namely at the level of the gastric mucosa, that

must be avoided and pharmacokinetic properties

that need to be improved and for these purpose

many delivery systems arise. Lipid Nanoparticles

allow an effective drug packaging and targeted

delivery, improving drug´s pharmacokinetics and

pharmacodynamics properties and avoiding some

of their side effects. In this work, two formulations

containing oxaprozin were developed:

nanostructured lipid carriers with and without

folate functionalization obtained by the addition of

a synthesised DSPE-PEG2000-FA conjugate. These

formulations revealed high stability, low

polydispersity and mean diameters that allowed

macrophages passive targeting along with high

encapsulation and loading capacity. The

formulations avoided the oxaprozin release in

simulated gastric fluid promoting its release on

simulated intestinal fluid, physiologic and

inflammatory medium, remaining only a small

amount entrapped on the lipid carrier matrix. MTT

and LDH assays revealed that the formulations

only seemed to present cytotoxicity in Caco-2 cells,

for oxaprozin concentrations superiors to 100 μM

and permeability studies in the same cell line

shown that oxaprozin encapsulation on the lipid

nanoparticles did not interfere with oxaprozin

permeability.


N. Bristowe1, P. Aguado-Puente

2,

R. Shirasawa3, B. Yin

2,4, P. Littlewood

5,6,

Ph. Ghosez7 and E. Artacho

2,8,9

1Department of Materials, Imperial College

London, London, UK 2CIC NanoGUNE and DIPC, San Sebastián, Spain

3Department of Earth Sciences, University of

Cambridge, Cambridge, UK 4Department of Engineering Mechanics, Zhejiang

University, Hangzhou, China 5Physical Sciences and Engineering, Argonne

National Laboratory, Argonne, USA 6Department of Physics, University of Chicago,

Chicago, USA 7Départment de Physique, Université de Liège,

Sart-Tilman, Belgium 8Theory of Condensed Matter, Cavendish

Laboratory, University of Cambride, Cambridge, UK 9Basque Foundation for Science Ikerbasque, Bilbao, Spain

[email protected]

O n t h e o r i g i n a n d s w i t c h i n g o f

a t w o - d i m e n s i o n a l e l e c t r o n

g a s u n d e r a t h i n p e r o v s k i t e

f i l m

Since the discovery of the two-dimensional electron

gas (2DEG) that forms at the interface between a

nanoscale thin film of LaAlO3 and a SrTiO3 substrate

[1], the research on this and similar systems has been

very active, leading to the discovery of a vast amount

of different properties with potential practical

applications [2]. The origin of such a 2DEG between

two band insulators has remained controversial for

some time. Our present understanding, in terms of a

polarization discontinuity at the interface will be

briefly reviewed, connecting with concepts that are

now more topically associated to topological

insulators [3].

Although the formation of a 2DEG has been

observed in other oxide heterostructures, the

prototypical system for these studies is still the

original LaAlO3/SrTiO3 interface. Very early after

the discovery of this system, the use of a

ferroelectric substrate was proposed as a way to

tune the population of the 2DEG. Since the

ferroelectric material possess a non-volatile

polarization, its switching with the application of

an external electric field could be used to increase

or decrease the polar discontinuity with the polar

LaAlO3 and consequently turn on and off the 2DEG.

First-principles simulations showed that this was

physically feasible [4] but the experimental

realization has not been achieved yet. A more

radical approach to this problem considers the

spontaneous polarization of a ferroelectric

material instead of the formal polarization of the

centrosymmetric LaAlO3, suggesting that a 2DEG

should also form under ferroelectric thin films due

to a polarization discontinuity with a dielectric

substrate or vacuum. If this were achieved a

number of possible applications can be envisaged,

such as non-volatile manipulation of the metallic

interface. Here we present a combination of

macroscopic models and first principles

simulations aimed at explaining the precise

conditions under which the formation of a 2DEG

under a ferroelectric thin films might be viable and

what the properties of the system would be. We

study the competition between the electronic

reconstruction and typical alternative screening

mechanisms, paying special attention to the

formation of polydomain structures. These results

are used to propose routes to favor the formation

of the 2DEG. The properties of the 2DEG formed at

realistic ferroelectric surfaces or interfaces are

analyzed using first principles simulations, taking

explicitly into account the interaction with the

substrate, the external fields, strain, and other

instabilities present in the materials. The switching

on and off of the 2DEG is obtained in the modeling

and the calculations, displaying a discontinuity in

the polarization and in the corresponding

screening mechanism (the free carriers of the

2DEG) equal to Ps / √3, Ps being the equilibrium

bulk polarization of the material.


R e f e r e n c e s

[1] A. Ohtomo and H. Y. Hwang, A high-mobility

electron gas at the LaAlO3/SrTiO3 heterointerface,

Nature 427, 423 (2004)

[2] J. Manhart and D. G. Schlom, Oxide Interface –

An opportunity for electronics, Science 327,

1607 (2010)

[3] N. Bristowe et al., Origin of two-dimensional

electron gases at oxide interfaces: insights from

theory, J. Phys.: Condens. Matter. Topical

Review, 26, 143201 (2014)

[4] M. Niranjan et al. Prediction of a switchable 2-

dimensional electron gas at ferroelectric oxide

interfaces, Phys. Rev. Lett. 103, 016804 (2009)


Alexander Bagaturyants

Photochemistry Center RAS, ul. Novatorov 7a,

Moscow, 119421, Russia

National Research Nuclear University MEPhI (Moscow

Engineering Physics Institute), Moscow, Russia

[email protected]

M u l t i s c a l e A t o m i s t i c M o d e l i n g

o f A m o r p h o u s O r g a n i c

F u n c t i o n a l M a t e r i a l s f o r

O p t i c a l C h e m i c a l S e n s i n g a n d

O L E D A p p l i c a t i o n s

Atomistic multiscale simulation is applied to

modeling amorphous organic functional materials

with specific optical or electronic properties.

Materials for optical chemical gas sensors and for

organic light-emitting devices (OLED's) are

considered as examples. The functionality of such

materials is provided by constituting molecules

that determine their specific functional properties.

In the case of sensing devices, these are so-called

indicator molecules (IMs) changing their optical

response (mostly, luminescence) upon interaction

with a target molecule (detected or analyte

molecule, AM). The goal of simulation in this case

is to predict the optical properties of the entire

structure (sensing material) and its response to

various AMs. In the case of OLED's, these are light-

emitting and electron- or hole-transporting

molecules. The goal of simulation here is to predict

the main electronic parameters of these molecules

that determine the efficiency of a particular OLED.

In both cases, the properties of functional

molecules strongly depend on their local

supramolecular environment, that is, on the

microstructure of the amorphous material.

Therefore, a multiscale atomistic approach is used,

in which molecular dynamics simulations are used

to describe the microstructure of the material, and

quantum chemical methods are used to calculate

the required electronic properties of the functional

molecules in the material. Commonly, a statistical

treatment is required to obtain the distribution of

wanted molecular properties or their averaged

values in the real amorphous material. Problems

arising at each step of modeling are analyzed, and

current approaches to their solution are discussed.

The possibilities of modern atomistic simulation

methods are considered using specific examples.

[1–8]

R e f e r e n c e s

[1] A.Ya. Freidzon, A.V. Scherbinin, A.A.

Bagaturyants, M.V. Alfimov., J. Phys. Chem. A,

115, no. 18, (2011) 4565.

[2] V. Chashchikhin, E. Rykova, A. Scherbinin, A.

Bagaturyants, Int. J. Quant. Chem., 112 (2012)

3110

[3] A. Bagaturyants , M. Alfimov, Atomistic

Simulation of Hierarchical Nanostructured

Materials for Optical Chemical Sensing.

Chemical Sensors: Simulation and Modeling,

Vol. 4: Optical Sensors, Edited by G.

Korotcenkov, Momentum Press, Ch. 1, 1.

[4] Vladimir Chashchikhin, Elena Rykova, and

Alexander Bagaturyants, J. Phys. Chem. Letters,

4 (2013) 2298.

[5] Svetlana Emelyanova, Vladimir Chashchikhin

and Alexander Bagaturyants, Chem. Phys. Lett.,

590 (2013) 101.

[6] Andrei A. Safonov and Alexander A.

Bagaturyants, J. Mol. Mod., 20 (2014) 2397.

[7] M. Bogdanova, S. Belousov, I. Valuev, A. Zakirov,

M. Okun, D. Shirabaykin, V. Chorkov, P. Tokar,

A. Knizhnik, B. Potapkin, A. Bagaturyants, K.

Komarova, M.N. Strikhanov, A.A. Tishchenko,

V.R. Nikitenko, V.M. Sukharev, N.A. Sannikova,

I.V. Morozov, Procedia Computer Science, 29

(2014) 740.

[8] Ksenia A. Romanova, Alexandra Ya. Freidzon,

Alexander A. Bagaturyants, Yury G.

Galyametdinov, J. Phys. Chem. A.,.


F i g u r e s

Figure 1: Hierarchical levels of a functional material for optical chemical sensors.

Figure 2: Scheme of multiscale atomistic simulation of a functional material for optical chemical sensors.


Bettencourt A1, Graça DF

2, Ferreira IFS

1,

Matos A1, Louro H

3, Silva MJ

3,

Almeida AJ1, Gonçalves LM

1

1Research Institute for Medicines (iMed.ULisboa),

Faculty of Pharmacy, Universidade de Lisboa,

Lisbon - Portugal 2REQUIMTE, Departamento de Química,

Faculdade de Ciências e Tecnologia, Universidade

Nova de Lisboa, Caparica, Portugal 3Departamento de Genética Humana, Instituto

Nacional de Saúde Dr. Ricardo Jorge, I.P. (INSA),

Lisboa, Portugal

[email protected]

D o e s s u r f a c e c h a r g e p l a y a

r o l e i n n a n o p a r t i c u l a t e -

s y s t e m s t o x i c i t y ?

When evaluating the toxicological effects of nano-

and microparticulate-systems, it is of utmost

importance to characterise the physicochemical

properties that are likely to influence cell and

tissue processes. In fact, specific physicochemical

properties of materials at the nano- and

microscale, such as size, charge or hydrophobicity

can greatly differ from the ones of the bulk

material and, thereby, can also drive unpredictable

biological interactions and effects. In particularly,

charge is one of the determinant properties of

biological interaction and cationic particles have

been shown to produce more effects on various

cells than neutral or anionic particles [1].

The aim of the present work was to compare the

toxicity of relevant biomedical acrylic based

particulate systems (polymethylmethacrylate –

PMMA), with different charges, within the same

size range (≈500nm). Specifically, PMMA

(negatively charged) and PMMA-Eudragit

(positively charged) formulations were considered.

Both particles, hereinafter represented by PMMAp

and PMMA-EUDp, were obtained by single-

emulsion solvent-evaporation methodology [2].

The surface charge of particles was evaluated

through zeta-potential measurement (Malvern

Zetasizer Nano Z). Surface charge was measured in

water dispersions, as well as in different media

aiming to identify cell culture conditions,

specifically ionic strength and FBS (fetal bovine

serum) concentration, that would have a direct

impact on particles charge.

Toxicological effects of both particulate systems

were evaluated by cytotoxicity (MTT assay), stress

response (H2DCFDA fluorescence test) and

genotoxicity (Comet assay) in fibroblast L929 cells

(as recommended by [3]). To confirm cellular

effects, uptake studies were also undertaken by

confocal microscopy analysis.

Results showed a significant reduction in the

absolute charge values of the particles with the

increase in the ionic strength of the media. It should

be pointed that at 0.12 M, which is the reported salt

concentration in physiological solution, both

particles showed a surface charge close to zero.

Also, results indicated that particles did not retain

their original charge once they were put in contact

with FBS. A complete inversion of PMMA-EUDp

surface charge was observed when exposed to FBS,

even at low concentrations (as low as 0.01%), while

PMMAp surface charge tends to neutrality.

Concerning the evaluation of particles toxicological

effects assessed by in vitro cellular assays, it was

concluded that both particles were internalized in

L929, after only 1h of exposure. Particles

cytotoxicity, evaluated by the MTT, did not show any

evidence of toxicity. Also, genotoxicity testing

showed that PMMAp and PMMA-EUDp were not

genotoxic in vitro, given that no significant induction

in DNA damage was found through the comet assay

for either particle type, as compared to negative

controls. Furthermore, using FPG-modified comet

assay, no significant oxidative DNA lesions occurred.

This absence of oxidative damage was confirmed

with the H2DCFDA oxidative stress assay, since no

significant rise in ROS was detected.

Overall, both PMMAp and PMMA-EUDp proved to

be safe on the tested cell line and within the

conditions employed on the various assays,

showing promising biological properties for


potential use as carriers in drug-delivery

applications. Considering that in the biological

tested conditions none of the evaluated particles

had positive charge, no conclusion could be made

in what concerns comparing the toxicity of

particles with opposite charge. Our study clearly

shows that careful standardization of procedures

must be undertaken, before evaluating potential

biomedical application of particulate systems.

A c k n o w l e d g e m e n t s :

Work supported by the Portuguese government

(Fundação para a Ciência e Tecnologia): research

project EXCL/CTM-NAN/0166/2012 and strategic

project PEst-OE/SAU/UI4013/2011.

R e f e r e n c e s

[1] Louro L, Bettencourt A, Gonçalves LM, Almeida

AJ, Silva MJ. Role of nanogenotoxicology studies

in safety evaluation of nanomaterials. In: S.

Thomas, Y. Grohens, N. Ninan, ed.

Nanotechnology Applications for Tissue

Engineering. Amesterdam: Elsevier. 2014 (In

Press)

[2] Bettencourt, A, Almeida, AJ. J Microencapsul.

29(4) (2012) 353-67.

[3] ISO 10993-5:2009: Biological evaluation of

medical devices -- Part 5: Tests for in vitro

cytotoxicity.


Francesco Bonaccorso

Istituto Italiano di Tecnologia, Graphene Labs,

Genova, Italy

[email protected]

S o l u t i o n p r o c e s s i n g o f

g r a p h e n e , r e l a t e d 2 d c r y s t a l s

a n d h y b r i d s t r u c t u r e s f o r

e n e r g y c o n v e r s i o n a n d

s t o r a g e

Technological progress is driven by developments

in material science. Breakthroughs can happen

when a new type of material or new combinations

of known materials with different dimensionality

and functionality are created. Graphene, because

of its many superior materials properties, has the

opportunity to enable new products [1]. Graphene

is just the first of a new class of two dimensional

(2d) crystals, derived from layered bulk crystals [2].

The assembly of such 2d crystals

(heterostructures) will provide a rich toolset for

the creation of new, customised materials [1,2].

Energy conversion and storage are two of the

grand challenges that our society is facing. New

materials and processes [1] can improve the

performance of existing devices or enable new

ones [2,3,4,5] that are also environmentally

benign. In this context, graphene and other 2d

crystals are emerging as promising materials [1-5].

A key requirement for these applications is the

development of industrial-scale, reliable,

inexpensive production processes [2], while

providing a balance between ease of fabrication

and final material quality with on-demand

properties.

Solution-processing [2] offers a simple and cost-

effective pathway to fabricate various 2d crystal-

based energy devices, presenting huge integration

flexibility compared to conventional methods.

Here I will present an overview of graphene and

other 2d crystals-based energy conversion and

storage applications, starting from solution

processing of the raw bulk materials [2], the

fabrication of large area electrodes [3] and their

integration in the final devices [6,7,8].

R e f e r e n c e s

[1] A. C. Ferrari, F. Bonaccorso, et al., “Scientific and

technological roadmap for graphene, related

two-dimensional crystals, and hybrid systems”

Nanoscale DOI: 10.1039/c4nr01600a (2014).

[2] F. Bonaccorso, et al., Production and processing

of graphene and 2d crystals. Materials Today,

15, 564-589, (2012).

[3] F. Bonaccorso, et. al., Graphene photonics and

optoelectronics, Nature Photonics 4, 611-622,

(2010).

[4] F. Bonaccorso, Z. Sun, Solution processing of

graphene, topological insulators and other 2d

crystals for ultrafast photonics. Opt. Mater.

Express 4, 63-78 (2014).

[5] G. Fiori, F. Bonaccorso, et al., Electronics based

on two-dimensional materials. Nature

Nanotech 9, , 768-779, (2014).

[6] F. Bonaccorso, et. al., Graphene, related two-

dimensional crystals, and hybrid systems for

energy conversion and storage. Science, 347,

1246501 (2015).

[7] J. Hassoun, F. Bonaccorso, et al. An advanced

lithium-ion battery based on a graphene anode

and a lithium iron phosphate cathode Nano

Lett. 14, 4901-4906 (2014).

[8] P Robaeys, F Bonaccorso, et al. Enhanced

performance of polymer: fullerene bulk

heterojunction solar cells upon graphene

addition. Appl. Phys. Lett. 105, 083306 (2014).


J. Borme1, G.M. Junior

1, M.F.

Cerqueira2, N. Vieira

1,3, P. Alpuim

1,2,

P.P. Freitas1

1INL – International Iberian Nanotechnology

Laboratory, Av. Mestre José Veiga, Braga, Portugal 2CFUM – Centre of Physics of the University of

Minho, Campus de Gualtar, Braga, Portugal 3IFSC – Physics Institute of São Carlos,

University of São Paulo, São Carlos-SP, Brazil

[email protected]

W a f e r - s c a l e f a b r i c a t i o n o f

s o l u t i o n - g a t e d g r a p h e n e

f i e l d - e f f e c t t r a n s i s t o r s f o r

b i o s e n s i n g a p p l i c a t i o n s

Graphene is a 2-dimensional material with a

honeycomb structure formed by sigma bonds

between three fourths of its valence electrons, the

remaining fourth forming a huge conjugated

electronic π system. Its transport properties are

therefore extremely sensitive to the charge

environment or to electric fields in its vicinity.

Graphene field-effect transistors (GFETs) take

advantage of this fact which, together with the

well-known density of states in the shape of Dirac

cones close to the valence and conduction band

edges, allows GFETs to be operated in n-, p- or

ambipolar channel mode by shifting the Fermi

level with the simple application of the

appropriate gate voltage. Combining such

electronic properties with a high chemical stability

in biological and chemical solutions, graphene is a

promising material for biosensing applications [1].

In order to detect specific biomarkers graphene

surface must be functionalized with recognition

biomolecules, such as antibodies [1]. For

graphene-based devices to be usable in real

applications it is necessary to process them at the

wafer-scale. However, the integration of graphene

with microelectronic devices has proven to be a

difficult task due to poor adhesion of graphene to

its insulating substrate after the transfer process

using a temporary polymeric substrate, normally

PMMA. This sets limits to the microfabrication

processes that can be used to pattern devices on

transferred graphene. The transfer of graphene on

top of pre-patterned contacts, without need for

further process, simplifies the fabrication.

Graphene produced over large areas by chemical

vapor deposition (CVD) shows a high crystalline

quality and almost 100% surface coverage which

allows it to be used as an electric insulation layer

in aqueous environment. This makes it possible to

operate GFETs in solution-gated configuration (SG-

GFET), more suitable for biosensing than the

traditional back-gated configuration due to a lower

operational voltage [1, 2]. More important, the

transistor transfer curve is highly sensitive to the

liquid gate electrolytic properties, such as ionic

strength, pH or any other parameter that changes

the electrical double layer that forms at the

solution-graphene interface.

Device Fabrication

In this work, a 200 mm silicon wafer with 200 nm

of thermal oxide and 3 nm of chromium as

adhesion layer was covered with 30 nm of gold.

Using optical lithography and ion milling, the wafer

was patterned with 126 devices (figure 1), each

with source and drain contacts separated by a gap

between 12.5 and 50 μm. An insulating layer of

320 nm of aluminium oxide was deposited on top

of the contacts using a lift-off technique, leaving

only 10 μm uncovered at the extremity of the

contacts.

Copper foil of 25 μm thickness and 99.999% purity

was cut into pieces with ≈20 mm side. These

substrates were loaded into a quartz tube and

heated to 1020 °C under low pressure argon flux.

Methane was introduced into the chamber,

thermally decomposing to produce monolayer

graphene on the copper catalyst. After deposition,

the conventional copper dissolution process using

PMMA as a temporary substrate was applied to

the samples. The floating graphene/PMMA

samples were then transferred onto different

areas of the prepared wafer, such that graphene

entirely covers the area of source and drain

contacts, but does not short-circuit the source and

drain pads. The PMMA temporary substrate was

removed using acetone. The quality of graphene

was assessed using Raman spectroscopy. The


finished set of devices was characterized

electrically at wafer-scale without further process.

Device Characterization

Phosphate buffered saline (PBS, pH 7.4, 150 mM)

solution was used in the measurements. A

platinum (Pt) wire was used to gate the transistor

through the solution. The experiments were

conducted by dipping a known volume of PBS onto

the graphene transistor sensing area.

Figure 2a shows the characteristic output curve at

different gate voltages (VG = -0.2, 0 and 0.2 V). A

linear behavior is observed, which is indicative of

ohmic contacts between graphene and the

contacts underneath.

The transfer curves of the devices show that the

graphene is unintentionally p-doped. The p-doping

is related to the process and the substrate (Figure

2b). Figure 2b shows that the transfer curve

changes with the ionic strength of the PBS

(1X = PBS 150 mM) in such a way that the

minimum conductivity point is shifted to lower VG

when the ionic strength increases. This is

consistent with the shorter Debye length in

solutions with high ionic strength [1].

G.M.J thanks CNPq for a PhD grant. N.V is thankful

to FAPESP for a post-doctoral grant.

R e f e r e n c e s

[1] Yan, F., Zhang, M., Li, J. Advanced Healthcare

Materials 3 (2014) 313-331.

[2] Mao, S. et al. Scientific reports 3 (2013) 1-6

F i g u r e s

Figure 1: (left) Picture of the microfabricated 200 mm wafer with 130 sets of contacts for graphene devices and several graphene/PMMA pieces

transferred. (top-right) Picture of the source and drain contacts (left and right respectively) in a device with a gap of 20 μm during the fabrication

process (before graphene transfer) and an accessory insulated voltage line (not used in this work). (bottom-right) Picture of a device during a

measurement with a platinum wire as a gate.

Figure 2: 2a (left) Output curves of the device for several VG values. 2b (right) Evolution of VG min as function of PBS ionic strength.


Joana Carrola1, Ivana Jarak

1, Rui

Silva1, António S. Barros

2, Ana M.

Gil1, M. Lourdes Pereira

1, M. Luisa

Corvo3, Iola F. Duarte

1

1CICECO, Departamento de Química, Universidade

de Aveiro, Portugal 2QOPNA, Departamento de Química, Universidade

de Aveiro, Aveiro, Portugal 3iMed.ULisboa,Departamento de Farmácia Galénica e

Tecnologia Farmacêutica, Faculdade de Farmácia,

Universidade de Lisboa, Lisboa, Portugal

[email protected]

M e t a b o l i c e f f e c t s o f s i l v e r

n a n o p a r t i c l e s a s s e s s e d b y

N M R m e t a b o l o m i c s

o f m i c e l i v e r a n d s e r u m

Silver nanoparticles (Ag-NPs) are among the

nanomaterials with highest propensity for human

exposure, arising from their established use in

wound dressings and increasing incorporation into

consumer products (e.g. clothing, food packaging),

mainly due to their remarkable antimicrobial

properties. However, there is a narrow window

between the bactericidal activity of Ag-NPs and

their toxicity to human cells[1], making the further

understanding of their biological effects a relevant

up-to-date subject. Development of metabolic

profiling (metabolomics) strategies for assessing

the cellular and systemic effects of these

nanoparticles may provide a unique and important

tool that can be broadly applied in the areas of

nanotoxicology and nanomedicine[2].

In this work, male mice were randomly divided into

three groups, a control group (n 10) and two

experimental groups (n 5 each) i.v. administered with

Ag-NPs suspensions (1 mg/mL) and sacrificed at 24

and 48 hours post-injection. A complete necropsy

was conducted on all mice. The necropsies included,

but were not limited to, examination of the external

surface, the cranial, thoracic, abdominal and pelvic

compartments, including viscera. Liver, spleen, heart

and kidneys were collected, rinsed with physiological

serum and weighted. Tissue histopathology

parameters and complete haemogram were also

assessed. Based on a preliminary biodistribution

study, liver tissues and blood serum were collected

for metabolic profiling analysis. In particular, the

samples were analysed by 1H Nuclear Magnetic

Resonance (NMR) spectroscopy, using High

Resolution Magic Angle Spinning (HRMAS) for direct

tissue analysis, and the spectral data subjected to

multivariate analysis, namely Principal Component

Analysis (PCA) and Partial Least Squares Discriminant

Analysis (PLS-DA), to highlight the metabolic

differences between the groups.

The livers of control and Ag-NPs-exposed mice

showed several significant differences in their

metabolic composition, already apparent by

simple visual inspection of 1H HRMAS spectra

(Figure 1A). Indeed, control and exposed groups

showed a trend for separation in the PCA scores

scatter plot and were clearly discriminated by PLS-

DA (Figure 1B). The main metabolic alterations

explaining this separation were in the levels of

glucose, glycogen and reduced glutathione

(decreased in exposed animals compared to

controls) and in the levels of choline compounds

and taurine (increased in mice exposed to

nanoparticles for 24 and 48h, respectively). In

regard to serum NMR profiles, while the most

apparent alterations were in the levels of

lipoprotein subclasses (Figure 2A), several other

differences could be found in small metabolites,

including increased levels of amino acids (alanine,

valine, lysine, histidine, tyrosine, phenylalanine),

creatine, choline and glycerol, together with

decreased levels of glucose, acetate and fumarate.

Interestingly, most of these changes showed a

stronger magnitude at 24h than at 48h of Ag-NPs

exposure, which explains the time-dependent

group separation observed in the PCA and PLS-DA

scores plots (Figure 2B). Overall, the results show

that Ag-NPs, at a sublethal dose, disturb cellular

and systemic metabolism, mainly affecting

pathways involved in energy production and

antioxidant protection.


R e f e r e n c e s

[1] Kim S and Ryu DY, J. Appl. Toxicol., 33 (2013) 78.

[2] Duarte IF, J. Control. Release 153 (2011) 34.

F i g u r e s

Figure 1: (left) A) Average

1H HRMAS NMR spectra of liver tissue from control mice (top), and mice exposed to Ag-NPs for 24h (middle) and

48h (bottom). B) Scores scatter plots obtained by PCA and PLS-DA of NMR liver spectra ( controls; exposed 24h; exposed 48h).

Figure 2: A) Average 1H NMR spectra of blood serum from control mice (top), and mice exposed to Ag-NPs for 24h (middle) and 48h (bottom).

B) Scores scatter plots obtained by PCA and PLS-DA of NMR serum spectra ( controls; exposed 24h; exposed 48h).


Filomena A. Carvalho1, Ana Filipa

Guedes1, Luís Sargento

2, Nuno

Lousada2, Carlos Moreira

3, Eduardo

Infante de Oliveira3, J. Braz Nogueira

3,

Nuno C. Santos1

1Instituto de Medicina Molecular, Faculdade de

Medicina, Universidade de Lisboa, Lisbon, Portugal 2Hospital Pulido Valente, Centro Hospitalar Lisboa

Norte, Lisbon, Portugal 3Hospital de Santa Maria, Centro Hospitalar Lisboa Norte,

Lisbon, Portugal

[email protected]

A F M a s a n a n o t o o l t o e v a l u a t e

p r o t e i n - c e l l i n t e r a c t i o n s a n d

c e l l - c e l l a d h e s i o n o n

c a r d i o v a s c u l a r p a t h o l o g i e s

Increased levels of plasma fibrinogen result in

changes in blood rheological properties, which are

not completely clarified [1,2]. Erythrocyte

aggregation has become an issue of increasing

interest, especially as an indicator of the associated

cardiovascular risk, since it is influenced mostly by

fibrinogen levels [2-4]. A better understanding of the

role of fibrinogen on erythrocyte aggregation in

cardiovascular pathologies patients may be relevant

for potential future drug interventions to reduce

aggregation and enhance microcirculatory flow

conditions. Our previous studies [5,6] demonstrated

the existence of a single-molecule interaction

between fibrinogen and a receptor on the

erythrocyte membrane, with a lower but

comparable affinity relative to platelet binding. The

receptor identified is not as strongly influenced by

calcium and eptifibatide (an αIIbβ3 specific inhibitor)

as the platelet receptor. The results from

Glanzmann thrombastenia (a rare hereditary

bleeding disease caused by αIIbβ3 deficiency) patients

showed, for the first time, an impaired fibrinogen-

erythrocyte binding. Correlation with genetic

sequencing data demonstrated that one of the units

of the fibrinogen receptor on erythrocytes is a

product of the expression of the β3 gene. More

recently, we also demonstrate that younger

erythrocytes may be the main cells responsible for

some cardiovascular diseases associated with an

increase on the fibrinogen content in blood [7].

The aim of this study was to understand how

fibrinogen influences erythrocyte aggregation by

cell-cell adhesion force spectroscopy measurements

using an atomic force microscope (AFM).

Additionally, we evaluated how this protein-cell

interaction constitutes a cardiovascular risk factor in

different cardiovascular pathologies.

Cardiovascular patients with heart failure (HF;

N=30), essential arterial hypertension (EAH; N=31)

and aortic stenosis (N=25), as well as 15 healthy

blood donors were engaged in this study. HF

patients were grouped according to two etiologies:

ischemic or non-ischemic HF. Fibrinogen-erythrocyte

binding measurements were conducted by AFM-

based force spectroscopy, in buffer, with the protein

covalently attached to the AFM tip. Erythrocyte-

erythrocyte measurements were conducted only for

healthy subjects, with one of the cells attached to

AFM tipless cantilevers and the other on the solid

substrate. Erythrocyte-erythrocyte adhesion forces

were measured in the absence and in the presence

of increasing fibrinogen concentrations.

Cell-cell adhesion data showed that increasing

fibrinogen concentrations there is an increase in the

work necessary for cell detachment, from 0.45 ±

0.04 fJ without fibrinogen to 12.0 ± 0.13 fJ at 1

mg/ml fibrinogen (p<0.001) (Figure 1A).

Concomitantly, average cell-cell detachment forces

increase from 72.0 ± 2.9 pN without fibrinogen to

250.4 ± 3.2 pN at 1 mg/ml fibrinogen (p<0.001)

(Figure 1B). We also observed a 3.5-fold increase on

the number of membrane tethers per curve on the

cell-cell detachment in the presence of fibrinogen 1

mg/ml, comparing with the experiments without

fibrinogen. AFM data allow, for the first time, the

quantification of the adhesion force necessary to

detach two erythrocytes in the presence of different

concentrations of fibrinogen. Our in vitro study tried

to mimic what happens in vivo on the human blood

flow. The results confirm that increasing fibrinogen


plasma levels are associated with the higher

tendency of erythrocytes to aggregate, probably by

transient simultaneous binding of the protein to two

cells, bridging them. This transient aggregation

impairs blood flow and is associated with a higher

risk of cardiovascular diseases.

Regarding the protein-cell interaction results, all

cardiovascular patients presented significantly

higher binding forces than healthy donors, despite

lower binding frequency (Figure 2). HF ischemic

patients presented higher forces than the non-

ischemic ones (74.9 ± 10.7 pN vs. 45.4 ± 5.6 pN;

p=0.021). Fibrinogen-erythrocyte interactions were

higher in all cardiovascular patients than the control

group. This could lead to changes on whole blood

flow, representing a cardiovascular risk factor. EAH

patients seem to have a higher cardiovascular risk

dependent of the increase of fibrinogen plasma

concentration levels. The results are relevant to

conclude on the degree of pathophysiological

relevance of fibrinogen and erythrocyte aggregation,

since an increment on both might induce a state of

microcirculatory slower flow, increasing the

probability of cardiovascular complications.

R e f e r e n c e s

[1] Delamaire and Durand, J Mal Vasc 15 (1990)

344-345

[2] Falcó et al., Clin Hemorheol Microcirc 33 (2005)

145-151

[3] Kwaan, Clin Hemorheol Microcirc 44 (2010)167-

176

[4] Pretorius and Kell, Integr Biol 6 (2014) 486-510

[5] Carvalho et al., ACS Nano 4 (2010) 4609-4620

[6] Carvalho and Santos, IUBMB life 64 (2012) 465-72

[7] Carvalho et al, Plos One 6 (2011) e18167

F i g u r e s

Figure 1: Cell-cell adhesion studies. Erythrocyte-erythrocyte adhesion in the absence and in the presence of increasing fibrinogen concentrations,

measured by AFM-based force spectroscopy. Quantification of the work (A) and the detachment force (B) necessary to break the interaction.

Figure 2: AFM-based force spectroscopy data of the interactions between fibrinogen and erythrocytes from patients with different

cardiovascular pathologies, and healthy blood donors (control subjects). Average values of force (A), and percentage of (un)binding events (B) for

all groups of patients and control. Data indicates that all groups of patients – heart failure (HF), essential arterial hypertension (EAH) and aortic

stenosis – have an increase on the force of the binding between fibrinogen and erythrocyte, despite their decrease on (un)binding frequency

(probability).


J. D. Costa1,2

, E. Paz1, J. Borme

1, S.

Serrano1, J. M. Teixeira

2, J. Ventura

2, R.

Ferreira1, P. P. Freitas

1,3

1International Iberian Nanotechnology Laboratory,

INL, Braga, Portugal 2IN-IFIMUP, Porto, Portugal

3INESC-MN and IN- Institute of Nanoscience and

Nanotechnology, Lisbon, Portugal

[email protected]

N a n o f a b r i c a t i o n o f M a g n e t i c

T u n n e l J u n c t i o n P i l l a r s

T a r g e t i n g N a n o - O s c i l l a t o r

A p p l i c a t i o n s

Magnetic Tunnel Junctions are Spintronic devices

constituted by two ferromagnetic layers separated

by a nanometric insulating barrier. The theoretical

predictions of giant Tunnel Magnetoresistance

(TMR) values in fully crystalline

Fe(001)/MgO(001)/Fe(001) structures [1] were soon

followed by its experimental verification [2,3]. Such

giant TMR effect arises from the conservation of the

coherence of the electron wave function during

tunneling across crystalline MgO and from the

smaller decay rate of the spin up states in the barrier

when compared to that of spin down states (spin

filtering effect) [4]. In state of the art CoFeB-MgO

MTJs, TMR ratios of up to 600% have been reported

[5]. In the low resistance x area (RA) range, which is

the most important for applications, TMR values of

138% have been demonstrated in MTJs with

RA~2.4 Ωμm2 (in unpatterned MTJs) [6].

These results promptly widened the prospect of

fabricating novel magnetic devices that operate

using spin transfer torque (STT) mechanisms. This

effect consists in the transfer of the moment of

magnetic spins from a polarized electrical current to

the ferromagnetic layers, thus allowing the

manipulation of the magnetization of nano-magnets

by means of local currents in opposition to magnetic

fields. Two of the best positioned STT applications to

reach the commercialization in the short term are RF

emitters resulting from persistent magnetic

dynamics driven by DC currents and non-volatile

magnetic random access memories.

In order to achieve high quality STT devices the

downscaling of MTJs until dimensions below 100 nm

is necessary. In this presentation we will describe

our nanofabrication process which is mainly based in

e-beam lithography and ion milling steps. Several

problems arise from the miniaturization of the MTJs

being one of the most prominent the material re-

deposition on the sidewalls of the nanopillars during

the ion beam etching. This re-deposition inflates the

final device critical dimension. More importantly, it

causes the electrical shunting across the barrier

which decreases the TMR. To remove the material

re-deposition a low angle milling is usually used after

the normal milling definition. However, low angle

millings create damages in the device edges,

generate shadowing effects that prevent the

formation of vertical sidewalls and decrease the

process uniformity due to clamps used at wafer

edges. The edge damage can be minimized by using

a low beam energy milling. However, the divergence

of the beam increases for lower beam energies and

thus a compromise must be found. Another problem

related to the nanofabrication process consists in

conferring mechanical stability to the devices while

keeping the nanopillars open on top. This structure

enables the microfabrication of the remaining

components of the device that allow the

reading/writing of the MTJ. To achieve this structure

a dielectric material is deposited after the nanopillar

definition and afterwards opened on the top of the

pillars. In order to open the MTJs, processes based

on lift-off and chemical-mechanical processes (CMP)

have been used. Despite the simplicity of the lift-off

process, the yield of the open nanopillars is

relatively low and it has a process time that can go

up to two weeks. Moreover, the process is

intrinsically worse for smaller nanopillars. As for the

CMP process, it is a very fast process that opens

more easily the smaller pillars. However, there are a

lot of residues arising from the planarization and a

good uniformity is difficult to achieve.

Here, we also propose the use of an ion beam

planarization step after the nanopillar definition.

This process is faster than the lift off and cleaner

that CMP and intrinsically better for the smaller

pillar sizes. Using the described process we were


able to achieve MTJs with RA below 1.5 Ωμm2 and

TMR up to 130%. We will also give a general

overview of the different devices fabricated, such

as the double barrier MTJs, magnetic vortexes and

MTJs with perpendicular magnetic anisotropy.

R e f e r e n c e s

[1] Spin-dependent tunneling conductance of

Fe/MgO/Fe sandwiches, W.H. Butler, X.-G.

Zhang, T.C. Schulthess, and J.M. MacLaren,

Phys. Rev. B 63, 054416 (2001),

[2] Giant tunnelling magnetoresistance at room

temperature with MgO (100) tunnel barriers,

S.S.P. Parkin, C. Kaiser, A. Panchula, P.M. Rice,

B. Hughes, M. Samant, and S.-H. Yang, Nat.

Mater. 3, 862 (2004),

[3] Giant room-temperature magnetoresistance

in single-crystal Fe/MgO/Fe magnetic tunnel

junctions, S. Yuasa, T. Nagahama, A.

Fukushima, Y. Suzuki, and K. Ando, Nature

Mater. 3, 868 (2004),

[4] Giant tunnel magnetoresistance in magnetic

tunnel junctions with a crystalline MgO(0 0 1)

barrier, S. Yuasa and D.D. Djayaprawira, J.

Phys. D 40, R337 (2007),

[5] Tunnel magnetoresistance of 604% at 300 K by

suppression of Ta diffusion in

CoFeB/MgO/CoFeB pseudo-spin-valves

annealed at high temperature, S. Ikeda, J.

Hayakawa, Y. Ashizawa, Y.M. Lee, K. Miura, H.

Hasegawa, M. Tsunoda, F. Matsukura, and H.

Ohno, Appl. Phys. Lett. 93, 082508 (2008).

[6] In situ heat treatment of ultrathin MgO layer

for giant magnetoresistance ratio with low

resistance area product in CoFeB/MgO/CoFeB

magnetic tunnel junctions, S. Isogami, M.

Tsunoda, K. Komagaki, K. Sunaga, Y. Uehara,

M. Sato, T. Miyajima, M. Takahashi, Appl.

Phys. Lett. 93, 192109 (2008).


Nitin M. Batra, Shashikant Patole, Ziwei Fan, Pedro M. F. J. Costa Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia [email protected]

T h e s t r u c t u r e a n d c h e m i s t r y o f C N T s i n e l e c t r i c a l

n a n o d e v i c e s f a b r i c a t e d b y b e a m d e p o s i t i o n

Despite the progress of the last two decades [1], the characterization of carbon nanotubes (CNT) at the individual structure level remains a non-trivial task [2]. In regards to the fabrication of electrical nanodevices, questions remain on the effect of using beam deposition methods [3]. Amongst others, the extent of modification of the CNT lattice, as well as the deposition tail of the patterned electrodes, are issues that have attracted little attention. Further to this, the structural and chemical nature of the deposited contacts is a subject not fully understood.

Using a plasma-enhanced chemical vapor deposition reactor, a mat of vertically aligned multi-walled CNT (MWCNT) were grown (Fig. 1a). The nanotubes were then characterized with electron microscopy (Fig. 1b) and Raman spectroscopy. After dispersing them in solution, the nanotubes were drop-casted onto patterned Si/SiO2 substrates and Pt electrodes deposited by either ion or electron beam methods (Fig. 1c). Besides characterizing the individual MWCNTs electrically, their structural and chemical integrities near the contact areas were analyzed. Assessment performed clearly showed beam deposition contamination of the nanotube interconnect along its length. Remarkably, there seems to be little mention of this critical issue in the literature.

R e f e r e n c e s

[1] De Volder, M. F. L.; Tawfick, S. H.; Baughman, R. H.; Hart, A. J. Carbon Nanotubes: Present and Future Commercial Applications. Science 339 (2013) 535.

[2] Costa, P. M. F. J.; Gautam, U. K.; Bando, Y.; Golberg, D. Direct imaging of Joule heating dynamics and temperature profiling inside a carbon nanotube interconnect. Nature Communications 2 (2011) 421.

[3] Murakami, K.; Matsubara, N.; Ichikawa, S.; Kisa, T.; Nakayama, T.; Takamoto, K.; Wakaya, F.; Takai, M.; Petersen, S.; Amon, B. et al. Transmission-Electron-Microscopy Observation of Pt Pillar Fabricated by Electron-Beam-Induced Deposition. Japanese Journal of Applied Physics 48 (2009) 06FF12.

F i g u r e s

Figure 1: a) As-grown sample of vertically aligned MWCNT; b) View of the internal bamboo-shaped structure of the nanotubes; c) Four-terminal electrical device of an isolated nanotube.


Fernando J.A.L. Cruz, José P.B. Mota Requimte/CQFB, Dept. Chemistry, Universidade Nova de Lisboa, Caparica, Portugal [email protected]

T h e r m o d y n a m i c s o f D N A S t r a n d s E n c a p s u l a t e d i n t o

E l e c t r i c a l l y C h a r g e d N a n o t u b e s

I. Introduction. Deoxyribonucleic acid (DNA) and single-walled carbon nanotubes (SWCNTs) are prototypical one-dimensional structures; the former plays a central role in chemical biology and the latter holds promise for nanotechnology applications [1-3]. From the point of view of biological purposes and DNA manipulation, carbon nanotubes have been proposed as templates for DNA encapsulation, intracellular penetration via endocytosis and delivery of biological payloads. Their interactions have been the subject of intense investigation, nonetheless, the corresponding molecular-level phenomena remain rather unexplored. Recently we have shown that, given a sufficiently large hydrophobic nanotube, the confinement of a DNA dodecamer is thermodynamically favourable under physiological environments (134 mM, 310 K, 1 bar), leading to DNA-nanotube hybrids with lower free energy than the unconfined biomolecule [4]. To accommodate itself within the D = 4nm nanopore, DNA’s end-to-end length increases from 3.85 nm up to approximately 4.1 nm, via a 0.3 nm elastic expansion of the strand termini. The canonical Watson-Crick H-bond network is essentially preserved throughout encapsulation, showing that contact between the DNA dodecamer and the hydrophobic carbon walls results in minor rearrangements of the nucleotides H-bonding. A diameter threshold of 3 nm was established below which encapsulation is inhibited. It is known that nanotubes can be electrically charged, either using an AFM tip and applying a voltage bias or by chemically doping the solids with p-type dopants to obtain positively charged nanotubes [5, 6]. The effect of charge density upon the energetics and dynamics of confinement needs to be addressed; because DNA’s outer surface is negatively charged (phosphate moieties), its interaction with a positively charged solid might lead to the occurrence of encapsulation which is inhibited for hydrophobic pores. We address this issue using enhanced sampling algorithms to probe the encapsulation mechanism of an atomistically detailed DNA

molecule, onto positively charged (q = + 0.05 e–/C)

SWCNTs of different diameters (3 nm, 4 nm), while employing precise physiological conditions.

II. Results & Discussion. In contrast with the purely hydrophobic (40,0) topology (D = 3 nm), the existence of an overall positive charge density on the solid indeed favours the encapsulation of the DNA molecule. To probe the thermodynamical stability associated with encapsulation, free-energy landscapes are built using the well-tempered metadynamics scheme [7] and two order parameters relating the distance between centres of mass of DNA and SWCNT, ξ1, and the end-to-end length of the biomolecule, ξ2. The corresponding free-energy maps recorded in Fig.1 show that: i) the nanopore endohedral volume (ξ1 <2) is the thermodynamically preferred region, by comparison with the bulk (ξ1 >2), ii) encapsulated DNA retains its translational mobility, diffusing freely between adjacent free-energy minima located within the solid and iii) whilst DNA maintains a quasi B-form end-to-end length within the (51,0) topology (D = 4 nm), the double-strand seems to suffer an elastic contraction when subjected to such a constraining volume as a (40,0) nanotube. The end-to-end length, L, probability distributions, P(Ω2), have been determined by independent umbrella sampling calculations and the results are recorded in Fig.2 for both topologies, (40,0) and (51,0), along with the previous results obtained for a purely hydrophobic (51,0) SWCNT [4]. It now becomes clear that charge density on the solid plays a paramount role upon the encapsulation mechanism; the elastic expansion of the double-strand observed for the (51,0) hydrophobic pore (L = 4.1 nm) is annihilated when the solid becomes electrically charged resulting in a maximum probability DNA end-to-end length of L = 3.73 nm, consistent with the canonical B-DNA form [8]. On the other hand, to accommodate itself within the constricting volume of the (40,0) topology, the DNA molecule undergoes a contraction and exhibits a maximum probability of occurrence at L = 3.54 nm.


A nanoscopic picture of the encapsulated DNA molecule can be produced by calculating the corresponding number density maps, as indicated in Fig.3 and obtained from atomically detailed mass histograms. Fig.3 reveals the existence of a cylindrical exclusion volume centred along the (51,0) main axis, where molecular density is ρ ≈ 0, which can be attributed to the strong electrostatic attraction between DNA ( PO4

3− ions) and the solid,

driving the former towards the walls and away from the nanopore center. Entropic effects caused by the pore narrowness of the (40,0) SWCNT force the DNA molecule to cluster tightly around the nanopore center, where it exhibits the region of highest molecular density.

As far as we are aware these observations are the first of their kind, and they come to pave the way for the design of smart nanotube based devices for in

vivo DNA encapsulation. A c k n o w l e d g e m e n t s

The authors would like to acknowledge Requimte/CQFB for generous CPU time. This work makes use of results produced with the support of the Portuguese National Grid Initiative (more information in https://wiki.ncg.ingrid.pt). F.J.A.L. Cruz gratefully acknowledges financial support from FCT/MCTES (Portugal) through grants EXCL/QEQ-PRS/0308/2012 and SFRH/BPD/45064/2008. R e f e r e n c e s

[1] H. Kumar et al., Soft Matter 7 (2011) 5898. [2] B.M. Venkatesan and R. Bashir, Nature Nano. 6

(2011) 615. [3] A.D. Franklin et al., Nano Lett. 12 (2012) 758. [4] F.J.A.L. Cruz et al., J. Chem. Phys. 140 (2014)

225103. [5] X. Zhao and J.K. Johnson, J. Am. Chem. Soc. 129

(2007) 10438. [6] F.J.A.L. Cruz et al., RSC Advances 4 (2014) 1310. [7] A. Barducci et al., Phys. Rev. Lett. 100 (2008)

020603. [8] J.M. Vargason et al., Proc. Nat. Acad. Sci. 98

(2001) 7265.

F i g u r e s

Figure 1: Free energy landscapes of DNA@SWCNT hybrids. ξ1 is the distance between centres of mass of the DNA and SWCNT, projected along the nanopore main axis, and ξ2 is the absolute distance between (GC) termini on opposite sides of the double-strand, equivalent to the DNA end-to-end length. The several free-energy minima along ξ1 demonstrate that the molecule is relatively mobile to translocate along the nanotube; interestingly, all the ξ1

minima are located along a quasi-linear path defined by ξ2 ≈ 3.7 nm (40,0) and ξ2 ≈ 4 nm (51,0) highlighting the enhanced thermodynamical stability corresponding to the canonical B form under the (51,0) topology.

Figure 2: Potential of mean force and probability distribution profiles. Ω2 corresponds to the end-to-end length of DNA. Symbols are umbrella sampling results and red lines are free fittings of data to

Gaussian statistics, Ω ∅exp Ω

: blue)

DNA@(40,0) SWCNT, black) DNA@(51,0) SWCNT, green) DNA@(51,0) hydrophobic SWCNT [4].

Figure 3: Number density maps of DNA@SWCNT. The existence of a cylindrical exclusion volume centred along the (51,0) nanopore main axis, ρ ≈ 0, is the direct consequence of strong electrostatic attractions between the heavily charged phosphate groups and the solid. The dashed lines indicate the boundaries of the nanotube.


Eunice Cunha1, M. Conceição Paiva1, M. Fernanda Proença2, Rui Araújo2 1Instituto de Polímeros e Compósitos/I3N, Universidade do Minho, Campus de Azurém, Guimarães, Portugal 2Centro de Química, Universidade do Minho, Campus de Gualtar, Braga, Portugal [email protected]

E x f o l i a t i o n o f g r a p h i t e u s i n g p y r e n e a n d p e r y l e n e

d e r i v a t i v e s

Since the isolation of graphene by mechanical exfoliation of graphite in 2004 [1] this material has been the focus of research among the scientific community. The excellent electronic, mechanical, thermal and optical properties of graphene [2] have reveled huge potential applications in various fields such as energy storage [3,4], composite materials [5] and sensor technology [6]. However, the production of graphene in large scale, with controlled quality and reasonable cost, is still a goal to achieve and became an important target and research topic.

The large scale graphene production processes are based on the conversion of SiC (silicon carbide) to graphene via sublimation of silicon at high temperature, chemical vapor deposition (CVD) growth, oxidation of graphite followed by exfoliation and reduction of the oxidation products, and exfoliation of graphite in organic solvents with high surface tension. These methods lead to large scale production, but present some disadvantages namely the high cost, or the production of graphene with structural defects or contaminants which are difficult to remove [7].

Some aromatic compounds such as pyrene and perylene derivatives, functionalized to render them amphiphilic, have been reported to effectively stabilize carbon nanotubes in aqueous suspensions [8,9]. Recently, the production of graphene based on graphite exfoliation through non-covalent interactions between graphene/pyrene and graphene/perylene derivatives was also reported [10]. This approach promotes the exfoliation and stabilization of graphene in water, leading to the production of few- and single- layer graphene without damaging its structure.

The present work reports the preparation of stable aqueous suspensions of few-layer graphene using low concentration solutions of pyrene and perylene derivatives. The suspensions were analyzed by UV-

Visible spectroscopy. The graphene-based materials deposited on surfaces were analyzed by Raman spectroscopy, showing the effectiveness of the exfoliation of pristine graphite. TEM images of the suspensions illustrate the formation of few layer graphene. Figure 1a presents the Raman spectra of graphite and few-layer graphene obtained by exfoliation with a pyrene derivative (Py-XGnP), and Figure 1b illustrates the TEM observation of the Py-XGnP.

A c k n o w l e d g e m e n t s

We gratefully acknowledge FCT for PhD grant SFRH/BD/87214/2012 and Post-doc grant SFRH/BPD/88920/2012.


R e f e r e n c e s

[1] K. Novoselov, A. Geim, S. Morozov, D. Jiang, Y. Zhang, S. Dubonos, I. Grigorieva and A. Firsov, Science, 306 (2004) 666-669.

[2] A. Geim and K. Novoselov, Nature Materials, 6 (2007) 183-191.

[3] M. Stoller, S. Park, Y. Zhu, J. An and R. Ruoff, Nano Letters, 8 (2008) 3498-3502

[4] S. Ghosh, X. An, R. Shah, D. Rawat, B. Dave, S. Kar, S.Talapatra, Physical Chemistry C, 116 (2012) 20688−20693.

[5] H. Kim, A. Abdala and C. Macosko, Macromolecules, 43 (2010) 6515–6530.

[6] X. Zhang, F. Gao, X. Cai, M. Zheng, F. Gao, S. Jiang and Q. Wang, Materials Science and Engineering C, 33 (2013) 3851–3857.

[7] V. Singh, D. Joung, L. Zhai, S. Das, S. Khondaker and S. Seal, Progress in Materials Science, 56 (2011) 1178–1271.

[8] T. Fujigaya and N. Nakashima, Polymer Journal, 40 (2008) 577–589.

[9] R. Araújo, C. Silva, M. C. Paiva, M. Melle Franco and M. F. Proença, RSC Advances, 3 (2013) 24535-24542.

[10] D. Parviz, S. Das, H. Ahmed, F. Irin, S. Bhattacharia, and M. Green, ACS Nano, 6 (2012) 8857–8867

F i g u r e s

Figure 1: a) Raman spectra of pristine graphite (XGnP) and exfoliated graphite using pyrene derivative (Py-XGnP); b) TEM image of Py-XGnP (on the left), magnified TEM Image (on the right) and XRD pattern of magnified Py-XGnP TEM image

1000 1500 2000 2500 3000

Intensity (a.u.)

Raman Shift (cm-1)

Py – XGnP

XGnP

a)

b)


J. A. Lawlor and M. S. Ferreira School of Physics and CRANN, Trinity College Dublin, Dublin, Ireland [email protected]

S u b l a t t i c e a s y m m e t r y o f s u b s t i t u t i o n a l l y d o p e d i m p u r i t i e s i n g r a p h e n e

Motivated by the recently observed sublattice asymmetry of substitutional nitrogen impurities in CVD grown graphene, we show, in a mathematically transparent manner, that oscillations in the local density of states driven by the presence of substitutional impurities are responsible for breaking the sublattice symmetry. While these oscillations are normally averaged out in the case of randomly dispersed impurities, in graphene they have either the same, or very nearly the same, periodicity as the lattice. As a result, the total interaction energy of randomly distributed impurities embedded in the conduction-electron-filled medium does not vanish and is lowered when their configuration is sublattice-asymmetric. We also identify the presence of a critical concentration of nitrogen above which one should expect the sublattice asymmetry to disappear. This feature is not particular to nitrogen dopants, but should be present in other impurities.


Quirina Ferreira1, Ana Margarida Bragança1, A.M. Ferraria2, A.M. Botelho do Rego2, Luís Alcácer1, Jorge Morgado1,3 1Instituto de Telecomunicações, Lisboa, Portugal 2Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Inst. Sup. Tecn., Universidade de Lisboa, Lisbon, Portugal 3Department of Bioengineering, Instituto Superior Técnico, Lisboa, Portugal

[email protected]

B i o c o m p a t i b l e a n d n a n o s t r u c t u r e d m o n o l a y e r s o n

g r a p h i t e f o r d r u g d e l i v e r y a p p l i c a t i o n s

The development of new nanostructured coatings with biomedical applications has been receiving greater attention in recent years due to the ability to give them specific and versatile functions by controlling their architecture. Stepwise methods, based on self-assembly properties of molecules, can provide a simpler and reproducible solution to prepare supramolecular structures with molecular control. The scanning tunneling microscope (STM) is a versatile tool to fabricate and control the molecular assemblies at the nanoscale. In particular, when operated at the solid/liquid interface, by placing a solvent droplet between the STM tip and the substrate, it is possible to add molecules in order to create organized structures [1-3].

We have been applying a stepwise method to built nanostructured and biocompatible monolayers composed of glycosaminoglycans adsorbed on Highly Oriented Pyrolitc Graphite (HOPG). The idea is to functionalize graphite with biomolecules that can act as anchor points to adsorb nanocarriers used in drug delivery. Figure 1 shows a monolayer composed of glucuronic acid (AcGl) and 1-heptanoic acid (AcHept). Both molecules were added to graphite at the same time and their adsorption was monitorired using STM at solid/liquid interface [1-3]. Theoretical simulations and X-ray photoelectron spectroscopy (XPS) showed that the stability of the monolayer is controlled by the H-bond interactions between the two acids. High resolution STM images show the formation of AcGl dimmers separated by lamellas with planar AcHept. At moment, we are using these monolayers to absorb an alpha-2-adrenergic receptor agonist encapsulated in a cyclodextrin. Drug release kinetic studies monitored by UV-spectroscopy are underway and preliminary results suggest that this monolayer is very stable and that it is possible to control the drug release in function of time.


We thank FCT-Portugal, under the project PEst-OE/EEI/LA0008/2014 and PostDoc grants SFRH/BPD/75338/2010, for financial support.

R e f e r e n c e s

[1] Q. Ferreira, Ana Margarida Bragança, L. Alcácer, J. Morgado, “Conductance of well-defined porphyrin self-assembled molecular wires up to 14 nm in length”, Journal of Physical Chemistry C, 118 (3), 7229 - 7234, 2014.

[2] Q. Ferreira, A. M. Bragança, N. M. M. Moura, M. A. F. Faustino, L. Alcácer, J. Morgado, “Dynamics of porphyrin adsorption on highly oriented pyrolytic graphite monitored by scanning tunnelling microscopy at the liquid/solid interface”, Applied Surface Science, 273, 220, 2013.

[3] Q. Ferreira, L. Alcácer, J. Morgado, “Stepwise Preparation and Characterization of Molecular Wires made of Zinc octaethylporphyrin complexes bridged by 4,4’-bipyridine on HOPG”, Nanotechnology, 22, 435604, 2011.

F i g u r e s

Figure 1: STM image (V=0.78V, It=0.42 nA) showing a lamellar structure of a self-assembled monolayer formed by co-adsorption of glucuronic acid and 1-heptanoic acid.


Fábio G. N. Figueiras1,2, Igor K. Bdikin3, Vitor B. S. Amaral1, Andrei L. Kholkin4 1 Physics Dep. & CICECO, Aveiro University, Aveiro, Portugal. 2 IFIMUP-IN, Sciences Faculty, Porto University, Porto, Portugal 3 Mechanics Eng. Dep. & TEMA, Aveiro University, Aveiro, Portugal. 4 Materials Eng. Ceramics Dep. & CICECO, Aveiro University, Aveiro, Portugal [email protected]

N a n o m e t r i c B i a s I n d u c e d P h a s e T r a n s i t i o n s i n m a t e r i a l s

We present a research that opens a new pathway for the production of microelectronic chips like sensors, transducers and memory. This technology enables to imprint nano scale (re)programmable multifunctional electronic devices from a single material basis.

By means of Surface Probe Microscopy (SPM) methods, namely suitable bias lithography stimulation and piezo response mode, it is possible to induce localized electrochemical states and stabilize local nanometric CO/OO regions which exhibit clear electric/magnetic/structural functional responses in contrast with the original matrix material properties. The mechanism that underlie such versatile phenomena is based on a set of SCE materials (strong correlated electron systems) having specific compositions near the threshold of relevant phase transitions, that drastically alter some structural, electric or magnetic transport properties and while enabling the concomitance of the distinct phases in nonometric regions [1].

R e f e r e n c e s

[1] F. G. N. Figueiras, I. K. Bdikin, V. B. S. Amaral, A. L. Kholkin, “Local bias induced ferroelectricity in manganites with competing charge and orbital order states”, Phys.Chem.Chem.Phys., (2014), 16, 4977

F i g u r e s

Figure 1: Consistent asymmetric effects of + or – bias poling are demonstrated in local SPM measurements of current versus voltage (left) and piezoresponse (right). Positive bias enhances electric conductivity while negative bias pooling sets a dielectric state and enables to observe piezoelectric loops.


Elvira Fortunato, Lidia Santos, Daniela Salgueiro, Rita Branquinho, Pedro Barquinha, Luis Pereira, Rodrigo Martins

Departamento de Ciência dos Materiais, CENIMAT/i3N, Faculdade de Ciências e Tecnologia - Universidade Nova de Lisboa and CEMOP/Uninova, Caparica, Portugal

[email protected]

A r e v i e w o n m e t a l o x i d e s e m i c o n d u c t o r s a p p l i e d t o

t r a n s i s t o r s : f r o m n a n o f i l m s t o n a n o p a r t i c l e s

In this work we will review some of the most promising new technologies for n- and p-type thin film transistors based on oxide semiconductors either in the form of nano-films or nanoparticles, with special emphasis to solution-processed, and we will summarize the major milestones already achieved with this emerging and very promising technology focused on the work developed in our laboratory. Transparent electronics has arrived and is contributing for generating a free real state electronics that is able to add new electronic functionalities onto surfaces, which currently are not used in this manner and where silicon cannot contribute [1,2]. The already high performance developed n- and p-type TFTs have been processed by physical vapour deposition (PVD) techniques like rf magnetron sputtering at room temperature which is already compatible with the use of low cost and flexible substrates (polymers, cellulose paper, among others). Besides that a tremendous development is coming through solution-based technologies very exciting for ink-jet printing, where the theoretical limitations are becoming practical evidences. In this presentation we will review some of the most promising new technologies for thin film transistors based on oxide semiconductors and its currently and future applications. R e f e r e n c e s [1] E. Fortunato, P. Barquinha, and R. Martins,

"Oxide Semiconductor Thin-Film Transistors: A Review of Recent Advances," Advanced Materials, vol. 24, pp. 2945-2986, Jun 2012.

[2] P. Barquinha, R. Martins, L. Pereira and E. Fortunato, Transparent Oxide Electronics: From Materials to Devices. West Sussex: Wiley & Sons (March 2012). ISBN 9780470683736.

F i g u r e s

Figure 1: High resolution FIB-SEM cross-section images and transfer characteristics of bottom gate TFTs produced with solution based GZTO and water-based AlOx.


A.Ya. Freidzon, A.A. Safonov, A.A. Bagaturyants

Photochemistry Center, Russian Academy of Sciences, Moscow, Russia

[email protected]

S p e c t r a l a n d T r a n s p o r t P a r a m e t e r s o f E l e c t r o n -

T r a n s p o r t i n g M a t e r i a l Bis(10-hydroxybenzo[h]qinolinato)beryllium

( B e b q 2 )

(Bis(10-hydroxybenzo[h]quinolinato)beryllium (Bebq2) is an electron-transporting and fluorescent material used in organic light-emitting diodes. It exhibits excellent emitting and charge-transport characteristics. In this work we present the results of quantum-chemical calculations of Bebq2 molecule and its dimers in order to better understand the mechanism of charge transport in this material and its luminescence properties.

We use multireference XMCQDPT2/CASSCF method to calculate the reorganization energies and hopping integrals for electron and hole transport in various dimers of Bebq2 that can occur in the solid phase as well as their absorption spectra. The same method is used to calculate the ionization potential, electron affinity and absorption and emission spectra of Bebq2 monomer.

The key feature in small-molecular organic semiconductors is charge localization. Our technique can directly show, whether the charge carrier is localized or delocalized depending on the arrangement of monomers in dimer. In this respect, our technique is superior to the energy splitting in dimer (ESID) method commonly used for calculating hopping integrals in organic semiconductors.

The potential energy profiles for electron and hole hopping in different dimers are constructed to explain different hopping rate for electrons and holes. The calculated spectra of dimers exhibit exciton splitting that ensures low emission intensity. Our computational results agree well with the experiment.

F i g u r e s

Figure 1: Chemical structure of Bebq2 molecule

Figure 2: Reorganization energy λ and hopping integral HAB in Bebq2 dimer.

N

ON

O

Be

Charge on A Charge on B Charge transfer coordinate

λ

Charge on A Charge on B Charge transfer coordinate

2|HAB|

Hopping barrier


Iúri Frias, Marina Pinheiro and Salette Reis

REQUIMTE, Departamento de Ciências Químicas, Laboratório de Química Aplicada, Faculdade de Farmácia da Universidade do Porto, Rua de Jorge Viterbo Ferreira, Portugal

[email protected]

D e v e l o p m e n t o f l i p i d n a n o c a r r i e r s - b a s e d

e p i g a l l o c a t e c h i n g a l l a t e f o r p r e v e n t i v e a n d t h e r a p e u t i c

s u p p l e m e n t a t i o n

Green tea is manufactured from the leaves of Camellia sinensis, and has been regarded to possess, anti-cancer, anti-obesity, anti-atherosclerotic, anti-diabetic, anti-bacterial, and anti-viral effects. The beneficial effects of green tea are atributed to the presence of the polyphenol (-)-epigallocatechin gallate (EGCG) (Fig. 1). EGCG has a stability dependent of the pH, temperature, and oxygen levels [1]. In this context, the encapsulation of EGCG in nanoparticles is an effective method to protect EGCG from adverse gastrointestinal conditions and to enhance its absortion. In this study, EGCG-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) nanocarrier systems were designed, developed and characterized. The lipid nanocarriers were synthetized to be biocompatible, and to improve the stability and bioavailability of EGCG for oral supplementation. The developed EGCG nanosystems revealed high encapsulation efficiency (approximately 80%), a sustained release in gastrointestinal environment and low cytotoxicity in the intestinal Caco-2 cellular lines. The developed nanocarriers-based EGCG delivery system can be exploited as a supplement and nutraceutical for the prevention and treatment of several diseases based on the supplementation of EGCG.

R e f e r e n c e s [1] Wang, D.; Taylor, W.; Wang, Y.; Wan, X.; Zhang.

J. International Journal of Nanomedicine, (2012) 1711-21.

F i g u r e s

Figure 1: Chemical structure of EGCG


Fu Guo-Dong and Yao Fang

School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, P.R. China

P r e p a r a t i o n o f F l u o r e s c e n t O r g a n o m e t a l l i c P o r p h y r i n

C o m p l e x N a n o g e l s

Among various fluorescence imaging technology, the near infrared (NIR) fluorescence imaging is expected to have significant impact on future personalized oncology therapy due to the very low tissue autofluorescence, high tissue penetration, and good image sensitively and noninvasively. Successful cancer NIR fluorescence relies on the development of NIR probes with good stability, high fluorescent intense and suitable chemical functionalities for targeting purpose.

1 Porphyrins,

with an emission maximum in the NIR region, have been well studied as photosensitizer for photodynamic therapy, because porphyrin is preferentially bound to telomere sequence, which includes more in chromosome of cancer cells than normal cell. Thus, base on the ability to accumulate many kinds of cancer cells, porphyrins are widely used in clinical to the treatment of tumors.

Interestingly, porphyrin can form complex

with 67

gallium (67

Ga) or 68

Ga, which has interesting physical properties and widely be used as nuclide for radiopharmaceutical research. A novel

approach to prepare well-defined poly(ethylene glycol) (PEG) fluorescent nanogels, with well-defined molecular structure and desired functionalities via reverse (mini)emulsion CuAAC (REM-CuAAC). This method allows the preparation of nanogels with size in the range of 30 and 120 nm. The fluorescence within the wavelength range of 700-800 nm, the functionality for cell affinity and the biocompatibility of nanogels make them applicable as an ideal NIR probe. R e f e r e n c e s [1] Guo-Dong Fu, Hua Jiang,Fang Yao,Li-Qun Xu,

Jun Ling,En-Tang Kang, Macromolecular Rapid Communications, 2012, 33(18), 1523-1527.

[2] SL. Luo, E. Zhang, Y. Su, T. Cheng, C. Shi. Biomaterials, 2011, 32, 7127-7138

[3] SA, Hilderbrand, R. Weissleder, Curr. Opin. Chem. Biol. 2010, 14(1), 71-79

F i g u r e s


André S. Gaspar1,4, F.E. Wagner2, V.S. Amaral3, Benilde F.O. Costa1, Luísa Durães4

1CEMDRX, Physics Department, University of Coimbra, Coimbra, Portugal 2Physics Department, Technical University of Munich, Garching, Germany 3Physics Department and CICECO, University of Aveiro, Campus de Santiago, Aveiro, Portugal 4CIEPQPF, Chemical Engineering Department, University of Coimbra, Polo II, Coimbra, Portugal

[email protected]

D e v e l o p m e n t o f a b i o d e g r a d a b l e m a g n e t i c

n a n o p r o b e u s i n g S P I O N s a n d A m a z o n i a n e s s e n t i a l o i l s

Currently, the demand for higher quality magnetic nanoparticles for use as a magnetic nanoprobe to assist in medical imaging techniques and cancer therapy by hyperthermia has been high [1]. Moreover, recent results regarding the phytochemistry benefits that some Amazonian essential oils possess have sparkled great interest in developing methods to use these oils in various medical treatments [2].

The main objective of this work is to develop a biodegradable magnetic nanoprobe which allies the superparamagnetism versatility of iron oxide nanoparticles with the benefits associated with Copaiba and Andiroba’s oils.

In order to improve the capabilities of this biodegradable magnetic nanoprobe, the synthesis method that originates the superparamagnetic iron oxide nanoparticles (SPIONs) [3] [4] was studied and certain paths were tested in order to improve that reaction product. Also, the cytotoxicity of the SPIONs was studied as well as the ability and effects of incorporating the SPIONs in Amazonian essential oils.

Particle size obtained for SPIONs was around 6 nm (figure 1). Mössbauer and XRD analysis indicate maghemite as their main iron oxide phase (figure 2). Also, small traces of magnetite proved to be present in some samples. VSM results showed a magnetization saturation of 57 emu/g, at 7 K, and 42 emu/g, at 300 K (figure 3). After incorporating the SPIONs in Copaiba and Andiroba essential oils these values dropped which indicates that a blocking effect occurs when the Amazonian oils are incorporated with SPIONS.

All the obtained results from the characterization data performed on the various samples seem promising towards having a biodegradable magnetic nanoprobe of SPIONs incorporated in Amazonian essential oils (figure 4). K e y w o r d s :

SPIONs; Amazonian essential oils; Copaiba; Andiroba; biodegradable magnetic nanoprobe; Mössbauer spectroscopy; XRD; VSM. R e f e r e n c e s

[1] Lodhia, J., Mandarano, G., Ferris, N.J., Eu, P. & Cowell, S.F., Development and use of iron oxide nanoparticles (Part 1): Synthesis of iron oxide nanoparticles for MRI. Biomedical imaging and intervention journal, 2010. 6(2): p. e12

[2] Pieri, F. A., MUSSI, M., & Moreira, M. A. S. (2009). Óleo de copaiba (Copaifera sp.): histórico, extração, aplicações industriais e propriedades medicinais. Rev. Bras. Plant. Med, 11, 465-472.

[3] Xu, Z., Shen, C., Hou, Y., Gao, H. & Sun, S., Oleylamine as both reducing agent and stabilizer in a facile synthesis of magnetite nanoparticles. Chemistry of Materials, 2009. 21(9): p. 1778-1780.

[4] Sun, S., Zheng, H., Robinson, D.B., Raoux, S., Rice, P.M., Wang, S.X. & Li, G., Monodisperse MFe2O4 (M= Fe, Co, Mn) nanoparticles. Journal of the American Chemical Society, 2004. 126(1): p. 273-279.


F i g u r e s

Figure 1: TEM image and respective size distribution calculation for the SPIONs.

Figure 2: Mössbauer spectroscopy and XRD diffractogram of the SPIONs

Figure 3: Magnetization measured as function of an applied field, at 300 K, to the SPIONs incorporated in Amazonian essential oils.

Figure 4: Application of an external magnetic field to SPIONs incorporated in Copaiba (top) and SPIONs incorporated in Andiroba (bottom).


Vítor M. Gaspar1, Cristine Gonçalves2, Duarte Melo-Diogo1, Elisabete C. Costa1, João A. Queiroz1, Chantal Pichon2, Fani Sousa1 and Ilídio J. Correia1

1CICS-UBI – Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal 2Centre de Biophysique Moléculaire, CNRS UPR4301, Inserm and University of Orléans, Orléans, France

[email protected]

S i m u l t a n e o u s D e l i v e r y o f D r u g s a n d G e n e s b y M u l t i -

b l o c k P o l y m e r i c N a n o m i c e l l e s f o r S y n e r g i s t i c C a n c e r

T h e r a p y

Presently cancer remains one of the most predominant incurable diseases and it is estimated that its worldwide incidence will continue to increase in the future [1]. From a clinical perspective chemotherapy is one of the best established methodologies for cancer treatment, being generally applied either as first line therapy for early stage disease, or palliative care in later phases. However, the administration of anti-tumoral drugs generally induces systemic cytotoxicity due to their poor selectivity to target cancer cells and tissue partition. Moreover, cancer drug resistance following a multi-stage treatment regime is common and this phenomenon further contributes to the ineffectiveness of chemotherapy. In this context the simultaneous delivery of different anti-tumoral drugs or drug-nucleic acid combinations arises as an exceptionally promising strategy for improving treatment efficacy and overcome cancer drug resistance [2]. Nonetheless, combinatorial therapy is remarkably challenging since nucleic acids are readily degraded in circulation and the simultaneous administration of multiple drugs provokes intolerable cytotoxicity.

The use of polymeric micelles is a valuable option to overcome such problems since these nanosized carriers can increase the bioavailability of bioactive molecules, i.e., drugs and genes, in the tumor site by the enhanced permeability and retention (EPR) effect. This characteristic contributes for reducing systemic cytotoxicity and improves treatment efficacy. Also, due to micelles unique hydrophobic-hydrophilic character which self-assembles into a core-shell structure, they can be used as a reservoir for encapsulating hydrophobic anti-tumoral drugs. In turn, this encapsulation promotes a sustained release during an extended time frame and increases intracellular drug concentration. These two parameters contribute for an enhanced therapeutic effect in comparison to standard chemotherapy. Including drug gene combinations is significantly more challenging as the physicochemical

nature of these distinct bioactive molecules demands a multi-block co-polymer with both hydrophobic and cationic properties so as to encapsulate drugs and complex DNA at the same time [2]. Thus for co-delivering drugs and nucleic acids the micelles must be self-assembled from polymeric nanomaterials in which the building blocks ought to be specifically tailored to have these properties.

Herein we provide, a brief focus on the different biocompatible and biodegradable polymers for micelles self-assembly will be provided. The use of biocompatible micelles for co-delivery of anti-tumoral compounds for cancer therapy will presented. Also, a particular emphasis will be given in the synthesis of innovative tri-block copolymers for gene-drug co-delivery (Figure 1) [3]. The application of this system for the delivery of Doxorubicin and Minicircular DNA (mcDNA) will be presented and the evaluation of its biological performance in vitro and in vivo will be provided.

R e f e r e n c e s

[1] Rebecca Siegel, Jiemin Ma, Zhaohui Zou and Ahmedin Jemal, CA: A Cancer Journal for Clinitians, 64(1), (2014), 9-29.

[2] Vítor M. Gaspar, Cristine Gonçalves, Duarte Melo-Diogo, Elisabete C. Costa, João A. Queiroz, Chantal Pichon, Fani Sousa and Ilídio Correia, Journal of Controlled Release, 189 (2014), 90-104.

F i g u r e s

Figure 1: Schematics of gene-drug (minicircle DNA-Doxorubicin) co-delivery concept using multi-block co-polymer micellar carriers.


Iaroslav Gnilitskyi1, Ihor Pavlov2, Serim Ilday2, Alberto Rota3, Massimo Messori4, Seydi Yavas2, Leonardo Orazi1 and F. Ömer Ilday2,5 1DISMI - Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Italy 2Department of Physics, Bilkent University, Ankara, Turkey 3 Department of Physics, Computer Science and Mathematics, University of Modena and Reggio Emilia, Modena, Italy 4Department of Engineering “Enzo Ferrari”, Modena, Italy 5Department of Eleckrical and Electronics Engineering, Bilkent University, Ankara, Turkey

[email protected]

S t r o n g l y a n i s o t r o p i c w e t t i n g o n h i g h l y - u n i f o r m s e l f - s i m i l a r

m o l y b d e n u m n a n o g r o o v e s

Nanostructure formation through surface treatment is mostly performed with well-established techniques including lithography and laser-induced periodic surface structuring (LIPSS). However, these techniques suffer either from the limited flexibility, high-cost, complex equipment, or suffer from the low-speed, problems of material control, and lack of uniformity and repeatability over large areas. Recently, a technique called Nonlinear Laser Lithography (NLL) was introduced, which allows fabrication of extremely uniform nanostructures, with excellent long-range repeatability and at high-speeds [1]. NLL can be applied to a variety of materials, including non-planar, even flexible surfaces. While NLL generates essentially LIPPS-type of nanostructures, it does so by utilizing nonlinear feedback mechanisms arising from the interaction of femtosecond laser pulses with the target surface, as well as from the laser-initiated chemical reaction. Key features, such as superior uniformity and ability to process non-flat surfaces are a direct consequence of the self-regulation provided by these feedback mechanisms.

Applications of surface-treated nanostructures have been demonstrated in various fields including electronics, optoelectronics, photovoltaics. Although the outcomes are encouraging, because of the problems of material and process control, they are still not suitable for transfer to industrial applications. It is appears that these problems can be overcome by NLL-induced nanostructures, thanks to their aforementioned superior features, with

potential for substantial impact in these and related fields. However, the technique is new and its potential for these applications needs to be evaluated systematically.

Here, we report on highly uniform, anisotropic, periodic molybdenum nanogrooves fabricated through NLL (Figure 1). We investigate the wettability characteristics of the nanogrooves as a strong candidate to be used for applications where anisotropic wetting of the surfaces is favored, ranging from microfluidics to energy applications to biomedical research such as gas seal conditions, self-cleaning surfaces, directional syringes, microprocessor cooling, high-efficiency hydropower turbines, and nanoscale digital fluidics. Wettability is investigated through contact angle measurements, where sessile drop methodology is used with distilled-deionized water as the test liquid. It is shown that the nanogrooves improved the hydrophilic behavior of the flat molybdenum surface significantly. Moreover, better wetting of the surface along the nanogrooves is observed. It is also shown that we can tune the wettability behavior, where the transition from Wenzel to Cassie regime is observed.

R e f e r e n c e s

[1] B. Oktem, I. Pavlov, S. Ilday, H. Kalaycıoglu, A. Rybak, S. Yavas, M. Erdogan, & F. O. Ilday, Nat. Photonics 7 (2013) 897.


F i g u r e s

Figure 1: SEM images of the Molybdenum surface ablated by fs-laser pulses at fluence of 0.7 J/cm2. (a) Nanotextured sample at a 100 mm/s scan speed.(b) Higher magnification image, (c and d) represent higher magnification image of (a), tilted on 45⁰ of (a).(e, f) shows the 2D FFT and 1D FFT images of the micrograph (b).


J. Patrício1, L. Pereira1,3, L. Rino1,3, M. Ribeiro2, A. Pinto2, A. Marques2, J. Gomes2 1University of Aveiro, Department of Physics, Campus de Santiago, Aveiro, Portugal 2CENTI – Centre for Nanotechnology and Smart Materials, Famalicão, Portugal 33I3N – Institute for Nanostructures, Nanomodeling and Nanofabrication, Aveiro, Portugal

[email protected]

O p t i m i z a t i o n o f p r o c e s s i n g a n d e n c a p s u l a t i o n c o n d i t i o n s

o f w h i t e O L E D d e v i c e s f o r d e c o r a t i v e l i g h t i n g

a p p l i c a t i o n s

Solid state lighting is one of the most attractive areas either for scientific and research groups in the industrial field [1]. Aside from the new and super-LEDs (Light Emitting Diodes) obtained from inorganic semiconductors a novel area of research has been growing towards a very useful technological solution for distinct and revolutionary applications: the OLEDs. These devices offer several advantages over conventional light emitters, namely low power consumption (for same bright compared to the conventional sources), high efficiency, large areas of display and the very attractive possibility of flexible devices (impossible for any other light emitting materials) [2].

However, there are still several scientific issues to be improved before these devices are suitable for market launching. The most relevant are lifetime, device architecture (simple as possible in order to be well reproduced), and optimization of the active layers, either with new materials or by improving the injection layers [3].

In this work, we address the optimization of performance of OLED devices for niche lighting applications considering assessment of the luminescent profile of the materials by a complete optical characterization so to efficiency design the device architecture. The focuses are general lighting with white-OLEDs and decorative lighting applications with coloured OLEDs. The optical properties of the materials processed into thin films (as used in device fabrication) will also be analysed, in order to collect data after the materials molecular conformation. Device fabrication and optimization of processing conditions via thermal evaporation is addressed and detail [4].

A complete optoelectronic characterization of each device using DC measurements, electroluminescence, thermal characterization of a matrix of devices and

corresponding brightness assessment was performed in order to obtain the figures of merit and assess the electrical injection properties. Additionally, the development of manual encapsulation aiming at stable, durable devices suitable for market applications was explored, with the ensuring study on lifetime of the device [5].

R e f e r e n c e s

[1] Kalyani, N.T. e Dhoble, S.J., Organic light emitting diodes: Energy saving lighting technology—A review. Renewable Sustainable Energy Rev., 2012. 16: p. 2696-2723.

[2] Park, J.W., Shin, D.C., e Park, S.H., Large-area OLED lightings and their applications. Semicond. Sci. Technol., 2011. 26.

[3] Pereira, L., 2012: Organic Light-Emitting Diodes: The use of rare-earth and transition metals; Pan Stanford Publishing.

[4] Tsujimura, T., OLED display structure, em OLED displays: fundamentals and applications. 2012, John Wiley & Sons. p. 24-39.

[5] Singh, J., Field emission organic light emitting diode, em Organic light emitting devices. 2012, InTech. p. 24-26.


V. M. Gouveia, S. Lima, C. Nunes and S. Reis

REQUIMTE, Laboratório de Química Aplicada, Faculdade

de Farmácia, Porto, Portugal

[email protected]

p H s e n s i t i v e l i p o s o m e s

l o a d i n g p r e d n i s o l o n e f o r t h e

t r e a t m e n t o f r h e u m a t o i d

a r t h r i t i s

Rheumatoid arthritis is a chronic systemic

inflammatory and autoimmune disease mainly

characterized by the progressive inflammation of

the synovial tissue of the body joints, destruction

of cartilage and further bone erosion. Currently

available treatment options include non-steroidal

anti-inflammatory drugs, glucocorticoids and

disease modifying anti-rheumatic drugs, either

used as monotherapy or in combination therapy.

However, all of these therapeutic strategies are

associated with severe side effects resultant from

limited selectivity and widespread biodistribution

of drug molecules into non-target tissues. In order

to overcome the drawbacks of conventional

therapy, the aim of the following dissertation is to

design pH-sensitive liposomes as suitable drug

delivery nanosystems for the treatment of

rheumatoid arthritis. Although these liposomes are

stable at physiological pH, they undergo rapid

liposomal destabilization under mildly acidic

conditions as those presented in endosomes of

target cells. Thus, promising to improve the

therapeutic efficiency of a commonly used

glucocorticoid - prednisolone disodium

phosphate -, due to liposomes ability to mediate

an intracellular, specific and controlled release of

the drug molecules, while limiting adverse off-

target unwanted effects. In this sense, designed

pH-sensitive liposomes with specific targeting

ligands, as the polyethylene glycol-folic acid or the

hyaluronic acid, were developed to enhance the

selective and efficient delivery of loaded drug into

target synovial macrophages and fibroblast.

Furthermore, the in vitro therapeutic performance

of the designed pH-sensitive liposomes was

evaluated, through the optimization of its lipid

composition, physicochemical characteristics, drug

release studies mimicking both biological

conditions at pH 7.4 and pH 5.0, cellular studies

and, as well as, the liposomal stability during

storage. The selectivity and stability of the

proposed targeted pH-sensitive liposomes

increases the bioavailability of the drug molecules

at the site of inflammation, once the liposomes

specifically internalize into the target cells where

they trigger the release of drug and thereby

enhance the therapeutic effect, reducing the

number of dosages and minimizing the well-known

deleterious side effects of prednisolone.


We thank the financial support through the project

PP-IJUP2011-279.


Muhammad Ilyas Sheikh, Mizi Fan and Zhaohui Huang

School of Engineering and Design, Brunel University, Uxbridge, Middlesex, United Kingdom

[email protected]

U s e o f N a n o - T e c h n o l o g y a n d N a n o m a t e r i a l i n t h e

D e v e l o p m e n t o f N a n o c o m p o s i t e C e m e n t i t i o u s

M a t e r i a l s Review for Future Research Openings

The main binder of concrete, Portland cement, represents almost 80% of the total CO2 emissions of concrete. This environmental impact can be reduced by limiting its production and developing alternative cementitious composites. Strength of cementitious material is also an essential requirement and cannot be trade-off by these alternative means. Development in nanotechnology has led researchers to investigate the complex structure of cement based materials at nano level to address both strength and environmental concerns. In this review paper nanotechnology pathways, recently been paved in the field of nano-composites for cementitious materials, are presented to understand how nano-science, nano-engineering and nano-indendation is making a great impact in the development of cementitious nanocomposite. Also generally used nanomaterial in the foregoing research to enhance strength, durability and other multifunctional properties of cementitious materials are highlighted. Among hundreds of nanomaterial available, only few of them are attracted by the researchers due to their great influence on properties the cementitious materials. Carbon nanomaterial such as carbon nanotubes (CNTs) and carbon nanofibers (CNFs) generally used in the cementitious materials for enhancing the compressive and flexural strength while nanoparticles of metal oxides such as TiO2, SiO2, Al2O3, Fe2O3 are reported to improve the durability and multifunctional properties such as self-cleaning and self-sensing ability. Moreover, studies on nano-clays, bio-nanomaterial and waste material supplemented with nanomaterial properties are also presented to bridge the gap between previous and future research for the development of environmental friendly high strength cementitious nanocomposite with multifunctional properties.

R e f e r e n c e s [1] Jayapalan, A.R., Lee, B.Y. and Kurtis, K.E.

(2013) "Can nanotechnology be ‘green’? Comparing efficacy of nano and microparticles in cementitious materials", Cement and Concrete Composites, vol. 36, no. 0, pp. 16-24.

[2] Sanchez, F. and Sobolev, K. (2010) "Nanotechnology in concrete – A review", Construction and Building Materials, vol. 24, no. 11, pp. 2060-2071.

[3] Pacheco-Torgal F, Miraldo S, Ding Y, Labrincha J. Targeting HPC with the help of nanoparticles. An overview. Constr Build Mater 2013;38:356–70.

[4] Davalos Jf. Advanace materials for civil infrastructure rehabilitation and protection. New York: Seminar at The Citty College of New York;2012.

[5] Makar, J. M., and Beaudoin, J. J. (2003).“Carbon nanotubes and their application in the construction industry.” Proc., 1st Int. Symp. On Nanotechnology in Construction, Paisley, Scotland, UK.

⁞

[90] Shiho Kawashima, Pengkun Hou, David J. Corr, Surendra P. Shah, Modification of cement-based materials with nanoparticles, Cement and Concrete Composites, Volume 36, February 2013, Pages 8-15, ISSN 0958-9465, 10.1016/j.cemconcomp.2012.06.012.

[91] Alireza Naji Givia*, Suraya Abdul Rashidb, Farah Nora A. Azizc and Mohamad Amran Influence of 15 and 80 nano-SiO2 particles addition on mechanical and physical properties of ternary blended concrete incorporating rice husk ash, Journal of Experimental Nanoscience, 2013 Vol. 8, No. 1, 1–18,

[92] Hamed Younesi Kordkheili, Salim Hiziroglu, Mohammad Farsi, Some of the physical and mechanical properties of cement composites


manufactured from carbon nanotubes and bagasse fiber, Materials & Design, Volume 33, January 2012, Pages 395-398, ISSN 0261-3069, 10.1016/j.matdes.2011.04.027.

[93] M. Aly, M.S.J. Hashmi, A.G. Olabi, M. Messeiry, A.I. Hussain, Effect of nano clay particles on mechanical, thermal and physical behaviours of waste-glass cement mortars, Materials Science and Engineering: A, Volume 528, Issue 27, 15 October 2011, Pages 7991-7998, ISSN 0921-5093, 10.1016/j.msea.2011.07.058.

F i g u r e s (Total 10)

Figure 1: Particle size and specific surface area related to concrete materials [03] (Adopted and modified from the article of Sanchez and Sobolev. Constr Build Mat 24, 2060–2071).

Figure 2: Graphical representation of data showing the enhancement of compressive strength and flexural strength using carbon fibres and carbon nanotubes; Extracted from data [42]

0

50

100

S1 S2 S3

CompressiveStrength (Mpa)

FlexuralStrength (Mpa)

CNT

Nanocomposite

Engineered Concrete


Yury V. Kolen’ko1, Xiao-Qing Bao1 and Pedro Alpuim1,2 1INL, Avenida Mestre José Veiga, Braga, Portugal 2Department of Physics, Universidade do Minho, Braga, Portugal

[email protected]

p - T y p e C u 2 O c o l l o i d s o p t i m i z e d f o r

p h o t o e l e c t r o c h e m i s t r y a n d e l e c t r o n i c s

Owing to appropriate direct band energy of ca. 2.1 eV, high absorption coefficient and high hole mobility, the cuprite Cu2O now stands as a competitive candidate as a photocatalyst for solar-assisted photoelectrochemical (PEC) H2 evolution from water. Cu2O is also a promising material for p-type metal-oxide semiconducting inks for solution-based printing of thin film transistors (TFTs), key components for microelectronics. Many examples of the synthesis of Cu2O micro- and nanocolloids, which allow control over the particle size and shape, are known. A major synthetic challenge, however, is up-scaling the preparation of Cu2O.

We use an automated synthesis system as a basis for the controlled large-scale surfactant-assisted synthesis of photoactive Cu2O submicroparticles (Figure 1). Structure, morphological peculiarities, as well as enhanced solar H2 evolution performance will be discussed. In particular, as a photocathode for PEC H2 evolution, bare Cu2O submicrocubes have a high onset potential of ca. 0.9 V versus the RHE at pH 1, which is significantly higher than the difference (∼0.54 V) between the Fermi-level (0.48 V vs. SHE) of Cu2O and the H

+/H2 redox

potential (0.06 V vs. SHE). This indicates a fraction of the photocurrent is induced by the reduction of Cu2O to Cu (0) according to the eq 1 [1]:

Cu2O + 2e− +2H

+ → Cu + H2O (1)

In addition, nearly monodisperse Cu2O nanocolloids were prepared in high yields through thermal decomposition protocol (Figure 2). Cu2O thin films were further fabricated by spin-coating of the nanocolloids on a 200-nm SiO2@Si wafer. Room temperature dark conductivity, σd, of the films, measured between parallel coplanar contacts, is thermally activated (Figure 3). σd is in the range 2.1 × 10

-5 Ω

-1cm

-1 - 1.2 × 10

-3 Ω

-1cm

-1,

while the activation energy of σd, Ea, extracted from temperature-dependent σd measurements in

the range 25 to 95 ºC, decreases from 0.44 eV to 0.25 eV, respectively.

R e f e r e n c e s

[1] A. Paracchino, V. Laporte, K. Sivula, M. Gratzel, E. Thimsen. Nat. Mater., 10 (2011) 456.

F i g u r e s


Igor Kuzmenko, Tetyana Kuzmenko, Yshai Avishai Ben Gurion University of the Negev, P.O.B. 653, Beer Sheva, Israel

[email protected]

T w o - C h a n n e l K o n d o E f f e c t i n C a r b o n N a n o t u b e Q u a n t u m

D o t

We consider Kondo tunneling through a junction as shown in Fig. 1(a): It is composed of two semi-infinite carbon nanotubes (CNT) that serve as left and right leads (CNTL and CNTR, respectively) attached on both sides of a short CNT quantum dot with an atom A having an s-wave valence electron of spin SA=1/2 implanted on its axis (CNTQDA). The two wave numbers (valleys) K and K’ (located on the two corners of the hexagonal Brillouin zone of the CNT) serve as two symmetry protected flavor quantum numbers ξ=K, K’. The CNTQDA is gated such that its (neutral) ground state consists of the caged atom with spin ±1/2 while its lowest excited (charged) states are singlet and triplet states, see Fig. 1(b). The energies of the singlet and triplet states satisfy inequality εS>εT. The Anderson model hybridizes lead and dot electrons with the same flavor and spin projection, and the Schrieffer-Wolf transformation, while mixing spin projections does not mix flavors, thereby realizing a two-channel Kondo physics. Employing the poor man's scaling technique to the Kondo Hamiltonian, it is shown that when the ultraviolet cut off energy εT-εF exceeds the Fermi energy εF (measured from the bottom of the conduction band), there are two different regimes of renormalization depending either the effective bandwidth D is above or below its critical value D1= εF, as shown in Fig. 2. The RG flow pattern of the effective couplings k

and j (corresponding to spin-independent potential scattering and spin-flipping exchange interaction) on the effective bandwidth D and the Fermi energy εF is shown in Fig. 3 for the energy of the triplet state εT=18 meV. The flow of k(D) as a function of D is shown in Fig. 3(a) and that of j(D) is shown in Fig. 3(b) for different values of εF. The behavior of the curves (1), (2) and (3) [εF≤1.7 meV] reveals a remarkable scenario of different RG domains: Within the interval D0>D>D1, the effective coupling

j(D) increases above j* (where j*=1/2 is the two-channel fixed point value for j), and then within the interval D<D1, j(D) decreases approaching j*. This behavior is unexpected, since in the standard two-channel Kondo model, the exchange coupling changes monotonically with D approaching j* for D→0. The non-monotonic behavior is caused by the crossover from the single-channel RG regime for D>D1 to the two-channel RG regime for D<D1. The Kondo temperature TK is shown in Fig. 4(a) as a function of εT and εF. It is seen that TK changes in between 0.5 K and 5 K for reasonable parameter values. The conductance G as function of the temperature T is shown in Fig. 4(b) for εT=18 meV and different values of εF. Note the non-monotonic behavior of the conductance for εF≤1.7 meV [curves (1)-(3)]. This exotic behavior is caused by the non-monotony of j(T) [see Fig. 3(b)]. In the standard 2CKE, G(T) is monotonic, depending on the bare value j0 of j. If j0<j*, (j0>j*), the conductance increases (decreases) monotonically with reducing T. Non-monotony of G(T) exposed here is the result of the crossover between different RG scaling regimes. One of the paradigms of the two-channel Kondo effect is that the physics related to over-screening is exposed only in the strong coupling regime, where T<TK. In this work we have demonstrated that the some physical phenomena related to over-screening can be exposed also in the weak coupling regime, where T>>TK. R e f e r e n c e s

[1] P. Nozières and A. Blandin, J. Physique, 41 (1980) 193.

[2] I. Kuzmenko, T. Kuzmenko and Y. Avishai, submitted to Phys. Rev. B; arXiv:1408.4935.


F i g u r e s

Figure 1: CNTL-CNTQDA-CNTR junction. (a) Schematic geometry of the junction including semi-infinite left and right leads, separated from a quantum dot of length 2h (that hosts a spin 1/2 atom A) by two barriers of width a. (b) Low energy levels of the quantum dot with (from below) the caged atom, followed by triplet and singlet atom-electron states.

Figure 2: Two different intervals of the effective bandwidth D, where different RG regimes are expected.

Figure 3: (a) k and (b) j as functions of D for εT=18 meV and different values εF. Here εS-εT=120 meV and curves (1)-(6) correspond to εF=1.5, 1.6, 1.7, 1.9, 2.1 and 2.3 meV, respectively.

Figure 4: (a) TK as a function of εT and different values of εF. (b) G as function of T for εT=18 meV and different values of εF. For both panels, curves (1)-(6) correspond to εF =1.5, 1.6, 1.7, 1.9, 2.1 and 2.3 meV, respectively. In panel (b), the dots from right to left correspond to D0, D1 and TK, separating the RG regimes from one another.


Seunghwan Lee and Nikolaos Nikogeorgos Department of Mechanical Engineering, Technical University of Denmark, Lyngby, Denmark

[email protected]

M u c o a d h e s i o n t o I m p r o v e S l i p p e r i n e s s o f M u c i n L a y e r s

Mucus gels are viscous slimes that are found from the surfaces of various internal organs, such as cervical, gastrointestinal, oculi, and reproductive tracts. A primary role of mucus gels in biological systems is known to be the protection against pathogens and mechanical insult as well as the lubrication of biological tissues. Mucins, the major macromolecular constituent of the mucus gels, not only serve as a building block of mucus gels, but also display unique slipperiness at the interface between engineering materials by forming lubricating films. Mucins and mucus gels have received particular interest in the areas of drug delivery [1-4] and biolubrication [5-9]. In the former case, the major interest lies in the mucoadhesive interaction between mucin/mucus and polymers that may be used as drug carriers so as to achieve better control in the delivery and release of drug molecules across the mucus gel on gastrointestinal organs. On the contrary, the latter case is primarily interested in understanding unique slipperiness of mucin/mucus layer at the interfaces of between biological tissues, biological tissue-biomaterials, or between engineering materials. As such, mucoadhesion and slipperiness of mucin and mucus layers appear to be two contradicting characteristics of mucins.

In this study, we demonstrate that mucoadhesion can be rather exploited to enhance the slippery nature of mucins layers. Firstly, the interaction between porcine gastric mucin (PGM) and chitosan were studied at low pH (about 3), where PGM and chitosan are negatively and positively charged, respectively. By varying the ratio of PGM to chitosan, a synergetic lubricating effect between PGM and chitosan based on their mucoadhesive interaction is observed at a hydrophobic interface comprised of self-mated polydimethylsiloxane (PDMS) surfaces. With increasing ratio of chitosan in PGM/chitosan mixture, the interaction of PGM with chitosan led to surface recharge (from negative to positive) and size shrinkage of the aggregates. This resulted in higher mass adsorption on the PDMS

surface with increasing weight ratio of [chitosan]/[PGM + chitosan] up to 0.50. While neither PGM nor chitosan exhibited slippery characteristics, coefficient of friction being close to 1, their mixture improved considerably the lubricating efficiency (coefficient of friction 0.011 at optimum mixing ratio) and wear resistance of the adsorbed layers (See Figure 1 below). A primary driving force of this synergy can be ascribed to the reduction of charges of PGM by the formation of aggregates with oppositely charged chitosan, and consequent suppression of the electrostatic repulsion between PGM on nonpolar PDMS surface, which tends to weaken the stability of the lubricating layer. Similarly, PGM, as well as bovine submaxillary mucin (BSM), showed improved lubricity by forming aggregates with polycations, such as poly(L-lysine) (PLL) or poly(allyl amine) (PAAm) at neutral pH (PBS).

Interestingly, the interaction of PGM with poly(acrylic acid) (PAA) also provided a similar synergic lubricating efficacy at neutral pH (7.4); while neither PGM nor PAA showed any effective lubrication of the sliding contacts of PDMS-PDMS, the mixture of them effectively reduced the coefficient of friction by more than an order of magnitude. This is fairly surprising because, as with PGM, PAA is also negatively charged at this pH, and thus electrostatic repulsion between them is expected. The overall charge of the aggregates, as estimated by zeta potential measurements, also remained negative, in the entire range of aggregates. This observation suggests that the synergetic improvement of lubricating properties of mucins from the interaction with mucoadhesive polymers cannot be ascribed to the reduced charges of mucin-polymer aggregates alone. Instead, it can be concluded that the mucoadhesive interaction between PGM and PAA as achieved via non-electrostatic interactions, such as hydrogen bonding or hydrophobic interaction, is strong enough to overcome electrostatic repulsion and form the


aggregates to assist the formation of network structure between mucins and polymer. Mucoadhesive polymers act as a physical crosslinker, and the cohesion within the lubricating layer is increased, and finally, chain interpenetration/bridging across the sliding interface bearing polymer layers can be minimized.

Nanoscale sliding contacts of the PGM-chitosan aggregate layers, as studied by atomic force microscopy, also showed lower friction forces in comparison to the reference buffer, primarily due to lower adhesion forces. However, the nanoscale tribological properties of the samples are in clear contrast to their macroscale properties. Firstly, both PGM and chitosan exhibit the lowest friction forces, whereas all the mixtures show higher frictional properties with the 0.50 [chitosan]/[biopolymer] weight ratio displaying the highest friction. Secondly, their frictional differences are much less pronounced at the scale studied by FFM. Integrated probes have a very low radius (~ 30 nm), and thus can penetrate the biopolymer layer under loading conditions. Hence, the friction experienced by the tip is due to its interaction with the substrate, and also due to the resistance applied to it by the adsorbed layer as it plows through it. At the nanoscale the tip and the PDMS are in mechanical contact due to the loading force, and, consequently, the tip has to plow through the adsorbed layer. A higher mass density, such as the film obtained from the [chitosan]/[PGM] at the ratio of 0.33 or 0.50 w/w, means higher number of chains and bonds encountered by the tip per unit length of sliding. Therefore, higher energy is dissipated per unit

length of sliding by the tip in breaking/disrupting these bonds (chitosan-PGM electrostatic bridges, PGM-PDMS hydrophobic bonds, chain entanglements) as it plows its way through the layer. Moreover, a higher degree of entanglement within the layer may result in a stiffer layer which could also explain a higher force needed by the tip to slide through it. The films formed from neat PGM or chitosan reveal the smallest friction forces, due to the lack of crosslinked bridges between the molecules on the same surface. R e f e r e n c e s [1] N. A. Peppas and J. J. Sahlin, Biomaterials, 17

(1996) 1553-1561. [2] N. A. Peppas and Y. Huang, Adv. Drug Delivery

Rev., 56 (2004) 1675-1687. [3] J. D. Smart, Adv. Drug Delivery Rev., 57 (2005)

1556-1568. [4] V. V. Khutoryanskiy, Macromol. Biosci., 11

(2011) 748-764. [5] G. Cassin, E. Heinricha and H. A. Spikes, Tribol.

Lett., 11 (2001) 95-102. [6] E. Perez and J. E. Proust, J. Colloid Interface Sci.,

118 (1987) 182-191. [7] M. Malmsten, E. Blomberg, P. Claesson, I.

Carlstedt and I. Ljusegren, J. Colloid Interface Sci., 151 (1992), 579-590.

[8] N. M. Harvey, G. E. Yakubov, J. R. Stokes and J. Klein, Biomacromolecules 12 (2011) 1041–1050.

[9] S. Lee, M. M. ller, K. Rezwan and N. D. Spencer, Langmuir, 21 (2005) 8344-8353.

F i g u r e s

Figure 1: Coefficient of friction obtained from the sliding contacts between PDMS surfaces as lubricated by the aqueous solutions of PGM (0.1 mg/mL), chitosan (0.1 mg/mL), and their mixtures (1:1, 0.1 mg/mL in total biopolymer concentration) (Left panel)


Sofia A. Costa Lima and Salette Reis REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Portugal

[email protected]

T e m p e r a t u r e - r e s p o n s i v e p o l y m e r i c n a n o s p h e r e s

c o n t a i n i n g m e t h o t r e x a t e a n d g o l d n a n o p a r t i c l e s : a m u l t i -

d r u g s y s t e m f o r t h e r a n o s t i c s i n r h e u m a t o i d a r t h r i t i s

Interest in developing multifunctional nanoparticles for a therapeutic application has recently gain particular focus in several diseases (cancer, infections, and inflammatory disorders) because of their unique theranostic properties. Theranostic combines therapeutics and diagnosis in a single multifunctional platform. These nano-carriers would preferentially target at the disease site, diagnose morphological changes of tissue of interest and provide effective therapy [1]. Multifunctional nanoparticles, containing stimuli-sensitive components, able to respond to internal and/or external triggers have appeared [2]. An example of such external trigger application is the photothermal driven drug delivery, through a nano-delivery system that, following intravenous administration, releases its payload at the site of interest upon application of a local near-infrared (NIR) light. NIR resonant nanomaterials, such as gold nanoshells [3] and gold nanoparticles strongly absorb NIR light producing local cytotoxic heat upon irradiation.

Chemo-photothermal therapy is a successful theranostic approach with the combination of chemotherapy and photothermal therapy that has recently emerged as a promising anticancer treatment [4]. Here, we intend to further explore the application of theranostic nanoparticles in the treatment of rheumatoid arthritis (RA). Permeability of rheumatoid synovium highly resembles solid tumours (e.g. leaky nature of their vasculature) [5] and the small synovial joints are within the penetration depth of NIR light, thus, multifunctional nanoparticles can be a promising tool for RA therapy.

In the present work, a novel stealth polymeric nanospheres platform able to carry anti-inflammatory drugs and an imaging agent was develop. The strategy to design a chemo-photothermal multifunctional platform was based on stealth polymeric nanospheres of pegylated-poly(DL-lactic-co-glycolic acid) (PEG-PLGA)

containing methotrexate (MTX) and gold nanoparticles (Au NPs) for the treatment of RA as (i) MTX is effective in the management of RA when administered systematically or locally through intra-articular injections [6] and (ii) Au NPs have been used in RA therapy per se [7], but can also be used as contrast agent for photoacoustic imaging [8] and as an external trigger for thermo-responsive controlled drug delivery. Through emulsion-diffusion evaporation technique MTX was incorporated in the pegylated polymeric nanospheres in the presence or not of Au NPs. In vitro dug release assays revealed pH and temperature gold nanoparticles-dependence. Blank nanospheres exhibited negligible in vitro cytotoxicity, while MTX-loaded nanospheres hampered monocytes and macrophages viability at a higher level than free MTX. Moreover, confocal fluorescent microscopy and flow cytometry revealed effective nanospheres internalization in human THP1 monocytes and macrophages. The cellular uptake was energy dependent and mediated by caveolae and clathrin-endocytosis mechanism. The MTX-loaded multifunctional nanospheres anti-inflammatory activity was evaluated using an in vitro model of RA involving monocytes and macrophages. Any change in the secretion of cytokines (IL-1β, IL-6 and TNF-α) in relation to the untreated stimulated cells indicate that the MTX and Au NPs incorporated on the multifunctional nanospheres retained their bioactivity and were able to reduce the inflammatory response in vitro. Results revealed that the MTX-loaded multifunctional nanospheres containing gold lead to a significant suppression of the pro-inflammatory cytokines produced by monocytes and macrophages, suggesting a favorable anti-inflammatory activity. These results confirm that the multifunctional nanospheres represent a promising theranostic platform for RA diagnosis and intracellular treatment, by combining methotrexate and gold nanoparticles for a highly effective targeted chemo-photothermal therapy.


R e f e r e n c e s [1] Muthu MS, Mei L, Feng SS, Nanomedicine

(Lond), 9 (2014) 1277. [2] Li M-H, Keller P, Soft Matter, 5 (2009) 927. [3] Lee SM, Park H, Choi JW, Park YN, Yun CO, Yoo

K-H, Angew Chem, 50 (2011) 7581. [4] Lee SM, Kim HJ, Kim SY, Kwon MK, Kim S, Cho A,

et al., Biomaterials, 35 ( 2014) 2272. [5] Levick JR, Arthritis Rheum, 24 (1981) 1550.

[6] Ramiro S, Gaujoux-Viala C, Nam JL, Smolen JS, Buch M, Gossec L, et al., Ann Rheum Dis, 73 (2014) 529.

[7] Tsai CY, Shiau AL, Chen SY, Chen YH, Cheng PC, Chang MY, et al., Arthritis Rheum, 56, (2007) 544.

[8] Yang S, Ye F, Xing D, Opt Express, 20 (2012) 10370.

F i g u r e s

Figure 1: Schematic illustration of the synthesis of multifunctional nanospheres through a modified solvent evaporation single emulsion method for RA chemo-photothermal therapy.


Lifeng Liu International Iberian Nanotechnology Laboratory (INL), Av. Mestre Jose Veiga, 4715-330 Braga, Portugal

[email protected]

E x t r a o r d i n a r i l y E f f i c i e n t E l e c t r o c a t a l y t i c H y d r o g e n

E v o l u t i o n A c h i e v e d b y A m o r p h o u s M o O x S y C a t a l y s t s

E l e c t r o d e p o s i t e d o n C r y s t a l l i n e T i O 2 N a n o t u b e

A r r a y s

Hydrogen evolution reaction (HER) is one of the most important half reactions in electrolyzers and photoelectrochemical cells. In order for these electrochemical devices to be widely employed, developing highly efficient, durable and low-cost HER electrocatalysts is critically needed. Molybdenum disulfide (MoS2) has recently emerged as a promising alternative catalyst to precious platinum to catalyze HER [1]. Despite remarkable progress made recently, the intrinsic poor electrical conductivity and unfavorably exposed active sites have hampered further improvement of the HER activity of MoS2. Herein, we report that amorphous MoOxSy electrodeposited on a high surface area crystalline TiO2 nanotube (TNT) array support can exhibit extraordinarily high electrocatalytic activity toward HER (see Figure 1), with unprecedentedly large current density of 115.8 mA cm

-2 at an

overpotential as low as 150 mV and an extremely low overpotential of 29.1 mV to reach a current density of 20 mA cm

-2 [2]. Furthermore, after iR

correction, a cathodic current density as high as 171.8 mA cm

-2 can be achieved at an overpotential

of 150 mV, the largest one reported so far to the best of our knowledge. Besides, the TNT supported MoOxSy catalyst (TNT@MoOxSy) also shows excellent durability in acidic solutions without obvious performance degradation after 3000 cyclic voltammetric scans (see Figure 2). The remarkable HER performance of the TNT@ MoOxSy can be attributed, on the one hand, to the high specific surface area and excellent electron transport property of the TNT/Ti array support; and on the other hand, possibly to the enhanced electrical conductivity of the catalyst itself because of the incorporation of oxygen. R e f e r e n c e s

[1] Vrubel, H.; Merki, D.; Hu, X.L. Energy Environ. Sci. 5 (2012) 6136-6144.

[2] L.F. Liu, under preparation

F i g u r e s

Figure 1: (a) HAADF image of a single TiO2@MoOxSy nanotube. Elemental maps of (b) Ti, (c) O, (d) Mo and (e) S.

Figure 2: The stability test of the TiO2@MoOxSy electrodes.


Zanna Martinsone, Anita Seile, Inese Martinsone, Pavels Sudmalis, Ilona Pavlovska, Ivars Vanadzins, Jelena Reste, Tija Zvagule, Natalja Kurjane

Rigas Stradins University, Institute of Occupational Safety and Environmental Health, Riga, Latvia

[email protected]

I n s t r u m e n t a t i o n f o r q u a l i f y i n g a n d q u a n t i f y i n g

n a n o p a r t i c l e s ’ e x p o s u r e i n t o o c c u p a t i o n a l e n v i r o n m e n t

The work characteristics, technology and tools are constantly changing, especially in countries such as Latvia, where since the early nineties the occupational environment is developing.

Occupational environment air quality is an important public health factor what influence persons’ health and well-being. Occupational air quality is characterized by physical (microclimate: air temperature, relative humidity, noise, lighting, etc.), chemical (dust, inorganic compounds: formaldehyde, carbon dioxide, organic compounds, etc.) and biological (dust mites, molds, etc.) pollutants. Much attention in the world is given to a very fine dust particles (PM10, PM2.5 and PM0.1, where the PM - Particular matter - particulates with a diameter of 10 mm, 2.5 mm and 0.1 mm or 100 nm - nanoparticles) in ambient and during last 10 years also in the occupational environment. Dust particles, especially nanoparticles, are identified as one of the emerging risk factors of occupational environment. Because the particles are finer and there many of them in the air their active surface area is greater. It is important to note the importance of the chemical composition of dust particles [1]. However, dust particles are not enough investigated, including adverse effects of nanoparticles in occupational environment and the health of workers, quality of life, work capacity and productivity.

There are little research in the world on nanoparticle exposure in the occupational environment and the information is controversial about the nanoparticles health effects related with nanoparticles chemical composition, structure, and induced effects. Open is the question of the toxicity of nanoparticles and correlation with particle properties. The assessment of harmful effects caused by the nanoparticles are used markers of inflammation and allergies, but there is lack of comprehensive information about

nanoparticle effects on different biological processes (oxidative stress, cancer aetiology, DNA damage) [2;3;1]. Therefore the studies of nanoparticle toxicity and nanoparticle exposure assessment methods and instrumentation are very topical with development of technology (especially nanotechnology) and the production of materials.

There is limited facifilities use the mobile and informative instrumentation for particle (also nanoparticle) quantifying and qualifying particles into occupational environment. However there are some instruments what were and are tested still into occupational environment of Latvia. According to data from the office environment (pilotproject data, see Figure 1), more useful and informative is "P-Trak ultrafine Particle Counter" Model 8525 (particle size: 20 - 1000 nm) for particle counting at occupational environment; other - "AeroTrak 9000" (nanoparticles size: 10 - 1000 nm; particle surface area are determined in two fractions: TB-traheobronhial (particle size <1000 nm) and A-alveolar (particle size <250 nm)) for particle surface area measurements (see Figure 2). For simultaneous particles size distribution, counting, surface area measurement, mass concentration measurements from experience very informative is ELPI+. Besides doing air measurements by ELPI+, it is possible collect dust samples also for dust gravimetric (sampling aluminium foils as collection substrate), chemical (on polycarbonate foils as collection substrate) and electron microscopy analyses (see Figure 1). Next step of testing this instrumentation will be welding and wood-working processes. All previously counted instrumentation for particles (also nanoparticles) exposure measurements gives possibilities to make air sampling as close as possible to workers breathing zone what is important for correct occupational exposure quantification and qualification. But personal sampling instrumentation for simultaneous nanoparticles’ counting, surface


area, mass, size distribution etc. parameters is still under development process and gives higher precision on workers’ personal exposure calculations. A c k n o w l e d g e m e n t s

Project “The development of up-to-date diagnostic and research methods for the risks caused by nanoparticles and ergonomic factors at workplaces”, Agreement No. 2013/0050/1DP/1.1.1.2.0/13/APIA/ VIAA/025 R e f e r e n c e s

[1] Maynard AD, Kuempel ED, Airborne nanostructured particles and occupational health, Journal of Nanoparticle Research, Issue 7(6) (2005), 587-614 page.

[2] Öberdörster G, Öberdörster E, Öberdörster J., Nanotoxicology: An emerging discipline evolving from studies of ultrafine particles, Environmental Health Perspectives, Issue 113 (7) (2005), 823-839 page.

[3] Cormier SA, Lomnicki S, Backes W and Dellinger B, Origin and Health Impacts of Emissions of Toxic By-Products and Fine Particles from Combustion and Thermal Treatment of Hazardous Wastes and Materials, Environmental Health Perspectives, Issue 114 (6) (2006), 810-817 page.

F i g u r e s

Figure 1: Laserprinters distributed dust particles (D1, D2, D3) sizes in nanometers (nm).

Figure 2: The alveolar fraction of dust particle surface area concentration in copy shop sampling by "AeroTrak 9000".


M. May, H. M. Wang, R. Akid

1. Material Engineering Department, Faculty of Engineering, Sebha University, Sabha - Libya 2. Materials and Engineering Research Institute, Sheffield Hallam University, UK 3. School of Materials, the University of Manchester. Manchester, U.K

E f f e c t s o f γ - A l 2 O 3 n a n o p a r t i c l e s o n t h e a d h e s i v e

s t r e n g t h o f c o m p o s i t e e p o x y / s o l - g e l m a t e r i a l s

The use of composite sol-gel/epoxy adhesive based on the combination of organic and inorganic components within the adhesive matrix have been studied. The incorporation of different amounts of γ-Al2O3 nano-particles into the adhesive matrix was evaluated. Mild steel specimens were prepared for lap joints, which were cured in an oven at 200°C for 16 hours. The bond strength of the sol-gel/epoxy matrix was investigated using a universal tensile test machine. Initially there was an increase in shear strength of sol-gel/epoxy adhesive with increase in γ-Al2O3 up to 4.0 wt%. This may be because the nano γ-Al2O3 increased the crosslinkage where many surface hydroxyl group on γ-Al2O3 materials and in silica sol-gel may react during the polymerisation stage as Al-O-Si bond and enhanced the adhesion strength per interaction area within the adhesive matrix. The maximum adhesive strength of composite sol-gel/epoxy adhesive recorded was 23±0.4MPa. However, as the level of these inorganic materials in adhesive matrix increased further, the adhesive shear strength gradually decreased. The reduction in the strength can be attributed to the increase in adhesive viscosity. The behaviour of the adhesive formulation changes from a liquid-like to a more solid-like state, reducing its wetting ability on the substrate surface, and thus decreasing shear strength.


Arben Merkoçi

ICREA & Catalan Institute of Nanoscience and Nanotechnology (ICN2), Bellaterra (Barcelona), Catalonia, Spain

[email protected] www.nanobiosensors.org www.icn.cat

N a n o b i o s e n s o r s A n d A p p l i c a t i o n s I n D i a g n o s t i c s

Nanomaterials (NM) with electrical and optical properties are playing a key role in the design of cutting edge biosensing technologies. Electrocatalytic, plasmonic and quantic properties of NMs such as gold nanoparticles, quantum dots or graphene while operating in simple plastic or paper matrix in diagnostic and safety/security applications will be shown. The effect of the platform architecture and other chemical and physical parameters upon biosensing and actuation including nano/micromotors pick-up or mixing operations will be discussed. The developed smart nanobiosystems are with interest for integration of diagnostic with therapies (nanotheranostics) or sensing and destruction/removal (sensoremoval) for health and environment industries. Examples related to protein (ex. neurodegenerative disease biomarkers), DNA (pathogen related) or cells (cancer cells) with interest for point of care applications will be shown. The developed devices and strategies are intended to be of low cost while offering high analytical performance in screening scenarios beside other applications. Special emphasis will be given to lab-on-a-chip platforms with integrated electrochemical detection with interest for either clinical or environmental monitoring (including sensoremoval). In addition simple paper-based platforms that operate in lateral flow formats with interest for heavy metals or protein detection will be shown. Various enhancement technologies ranging from microfluidics architectures changes, in-chip re-circulations as well as actuation via nano/micromotors able to either pick-up analytes or improve reaction medium in solid-liquid phase sensing technologies will be discussed.

R e f e r e n c e s [1] C. Parolo, A. Merkoçi, “Paper based

nanobiosensors for diagnostics”, Chem. Soc. Rev., 42 (2013), 450—457

[2] A. M. Lopez_Marzo, J. Pons, D. A. Blake, A. Merkoçi, “All-Integrated and Highly Sensitive Paper Based Device with Sample Treatment Platform for Cd2+ Immunodetection in Drinking/Tap Waters”, Anal. Chem., 85 (2013), 3532–3538

[3] E. Morales-Narváez, A. R. Hassan, A. Merkoçi, “'Graphene oxide as a pathogen-revealing agent: sensing with a digital-like response', Angew.Chem.Int.Ed. 52 (2013), 13779 –13783.

[4] E. Morales-Narváez, H. Montón, A. Fomicheva, A. Merkoçi, “Signal Enhancement in Antibody Microarrays Using Quantum Dots Nanocrystals: Application to Potential Alzheimer’s Disease Biomarker Screening”, Analytical Chemistry, 84 (2012), 6821−6827

[5] A. Escosura-Muñiz, A. Merkoçi, “Nanochannels Preparation and Application in Biosensing”, ACS Nano 6 (2012), 7556–7583

[6] E. Morales-Narváez, M. Guix, M. Medina-Sánchez, C. C. Mayorga-Martinez, A. Merkoçi, “Micromotor Enhanced Microarray Technology for Protein Detection”, Small 2014, 2542–2548.

[7] E.Morales-Narvez, A.-R. Hassan, A. Merkoçi, Graphene Oxide as a Pathogen-Revealing Agent: Sensing with a Digital-Like Response, Angwandte Chemie, 52, 13779–13783, 2013


Farzin Mohseni, M. J. Pereira, N. M.

Fortunato, J. S. Amaral, A. C. Lourenço,

J. M. Vieira

Department of Physics, University of Aveiro, 3810-193,

Aveiro, Portugal

[email protected]

M a g n e t i c a n d m o r p h o l o g i c

p r o p e r t i e s o f A l n i c o - b a s e d

r a r e - e a r t h f r e e p e r m a n e n t

m a g n e t s

Due to recent dramatic increases in the price of

rare-earth elements, rare-earth free permanent

magnet research is nowadays a very active field [1].

Alnico V alloys, first discovered in the 30’s, are hard

ferromagnets, with high working temperatures,

albeit with modest coercivity, below 1 kOe [2]. This

makes their energy product (~12 MGOe) compare

unfavorably with rare-earth based NdFeB magnets

(~55 MGOe). Recently, an unusually high coercivity

value, up to ~10 kOe, was reported for DC-sputtered

Alnico V thin-films on Silicon substrates [3, 4], due to

the formation of a novel Body Centered Tetragonal

Fe-Co-Si phase, a result of diffusion of Si ions from

substrate to thin film. This diffusion mechanism is

still unclear, and the chemical composition and

saturation magnetization of this novel phase are not

yet characterized.

We report on the effects of deposition temperature

and post heat treatments on the morphology and

magnetic properties of Alnico V thin films prepared

by RF-sputtering. The sputtering target was of

commercial Alnico V alloy, and substrates were of

700 µm thick Si(100). Samples of 180 nm thickness

were prepared at different deposition temperatures,

ranging from room temperature to 560 C. Post-

deposition heat treatments in vacuum at 600, 800

and 900 C, followed by quenching in liquid Nitrogen

and slow-cooling, were performed.

Atomic Force Microscopy (AFM) shows that both an

increase of deposition temperature as well as post

heat treatments lead to a considerable increase of

roughness, from <0.8 nm to 80 nm, for heat

treatments at 600 C, and 50 nm for a deposition

temperature of 500 C (Figure 1).

The chemical composition of the thin films was

analyzed by Electron Dispersion Spectroscopy (EDS)

in a Scanning Electron Microscope (SEM). The

composition of films deposited at room

temperature, matches that of the target, while for

higher substrate temperatures the ratio between

transition metals is altered, and post-deposition

heat treatments introduce contaminations to the

thin films. Figure 2 shows the cross-section SEM

image of the as-made and heat treated films.

Magnetization analysis using a Vibrating Sample

Magnetometer (VSM) shows that substrate

temperature affects the saturation magnetization,

lowering it drastically for high temperatures. In the

case of heat treatments this decrease is smoother,

but still quite substantial, particularly for quenched

samples. Coercivity is unaffected by deposition

temperatures in this range, while increasing

considerably (from < 20 Oe for as-deposited films up

to 480 Oe) in heat-treated samples (Figure 3).

Future studies will focus on film thickness and

substrate temperature optimization, and the control

of surface roughness under heat-treatments, by

adding a capping layer to the films (Ag, Ta),

preventing also the observed oxidation of the

surface during heat treatment and quenching.

R e f e r e n c e s

[1] Narayan Poudyal and J Ping Liu, “Advances in

Nanostructured Permanent Magnets Research”,

Journal of Physics D: Applied Physics 46 (2013)

043001 (23pp).

[2] K. H. J. Buschow, “New Developments in Hard

Magnetic Materials”, Reports on Progress in

Physics 54 (1991) 1123-1213.

[3] O. Akdogan, G. C. Hadjipanayis, “Alnico Thin Films

with High Coercivities up to 6.9 kOe”, Journal of

Physics: Conference Series 200 (2010) 072001.

[4] O. Akdogan, W. Li, G. Hadjipanayis, “High

Coercivity pf Alnico Thin Films: Effect of Si

Substrate and the Emergence of Novel

Magnetic Phase”, Journal of Nanoparticle

Research (2012) 14 891.



We acknowledge funding from FEDER/COMPETE through FCT, FCOMP-01-0124-FEDER-037271 (PEst-C/CTM/LA0011/2013) and EXPL/CTM-NAN/1614/2013 - FCOMP-01-0124-FEDER-041688 F i g u r e s

Figure 1: AFM image of a) as-deposited, b) after heat treatment and c) deposited at 560 C.

Figure 2: Cross sectional SEM image of a) as-deposited, b) after heat treatment

Figure 3: Effects of a) heat treatment followed by slow cooling, b) heat treatment followed by quenching and c) deposition temperature on hysteresis loop


Lars Montelius

INL - International Iberian Nanotechnology Laboratory,

Braga, Portugal

[email protected]

www.inl.int

B r i d g i n g t h e m a t e r i a l s g a p

t h r o u g h r a d i c a l I n n o v a t i o n s

Nanotechnology is a Key Enabling Technology with

promises for making solid contributions to the grand

challenges of today, such as sufficient sustainable

energy supply, access to clean water, care of the

elderly population and making cities ready for the

globalization.

At INL, the Internatioal Iberian Nanotechnology

Laboratory, we are implementing a full ecosystem

for nanotechnology innovation and science. I will

discuss about our offers and describe the

possibilities that exist for collaboration with

university and institutions and companies.

Then I will discuss about how nanotechnology could

be of importance to bring added value to products

and services. I will also review some areas of

nanotechnology that recently has been deployed

giving rise to radical innovation and business

development.

In particular, I will address the accelerated

development of LEDs and the consequences on

lighting. Lighting is increasingly becoming an integral

part of the Digital Age. The lighting of the future will

be more attractive, individually tailored and

integrated into Smart Buildings and Smart Cities.

Even today, you can access the Internet via LED

luminaries.

By creating working and living environments with

situation-specific forms and levels of sensory

stimulation, we can improve the conditions for

productivity, learning, health, comfort and well-

being. Ever more people talk about Smart Lighting,

i.e. a lighting that is adaptive (on demand),

interactive (by control) and dynamic (color &

intensity). The main basis for Smart Lighting is that

the LED and ICT of today creates a more or less

unlimited flexibility to deliver a dynamic user

adapted light - the right light, at the right place, at

the right time, for each and everyone.

In the end I will discuss about the need for

articulation in science and innovation actions.


Artur M. Pinto1,2, Carolina Gonçalves

1, Inês

C. Gonçalves2, Fernão D. Magalhães

1

1LEPABE, Faculdade de Engenharia, Universidade do

Porto, Porto, Portugal 2INEB, Universidade do Porto, Porto, Portugal

[email protected]

E f f e c t o f b i o d e g r a d a t i o n o n

P L A / g r a p h e n e - n a n o p l a t e l e t s

c o m p o s i t e s m e c h a n i c a l

p r o p e r t i e s a n d

b i o c o m p a t i b i l i t y

Two types of graphene-nanoplatelets (GNP-M and GNP-

C) were incorporated in PLA (poly(lactic acid)) by melt

blending. Materials were biodegraded during 6 months

and characterized by XRD, tensile tests, DMA and

biocompatibility assays. For both fillers, low loadings

(0.25 wt.%) improved mechanical properties and

decreased their decay until 6 months biodegradation.

PLA degradation decreased its toughness (AUC) by 10

fold, while for PLA/GNP-M and C after 6 months

degradation, toughness was only reduced by 3.3 and 1.7

fold, respectively. Comparing with PLA, PLA/GNP-M and

C composites presented similar (HFF-1) fibroblasts

adhesion and proliferation at the surface and did not

released toxic products (6 months).

Introduction Graphene is a single layer of sp

2 carbon atoms arranged

in a honeycomb structure and possesses extraordinary

mechanical strength and an extremely high surface

area. [1] A commercial available product, with reduced

cost comparing with single layer graphene, graphene

nanoplatelets (GNPs), are constituted by few stacked

graphene layers, possessing oxygen containing

functional groups in the edges. GNPs present high

aspect ratio, thus forming a percolated network in

composites, with large interfacial interaction between

platelets and polymer matrix, mainly in the edges,

resulting in effective load transfer and increased

strength. [2] Moreover, these materials were shown to

be non-toxic when incorporated in low percentages into

PLA. [3] The potential of GNPs as polymers fillers, has

been observed in our previous study, in which

improvements in mechanical properties of PLA thin

films were obtained at filler loadings bellow 1 wt.%.

Solvent mixing was used for GNPs incorporation, [4]

however the use of solvents should be avoided due to

the toxicity of residues that may remain in the

materials, and for industrial workers [5]. Lahiri et al.

improved ultrahigh molecular weight polyethylene

mechanical properties producing composites by

electrostatic deposition of GNPs 1 wt.%. However,

composites were toxic to osteoblasts because filler

leaching occurred. [2] Thus, melt blending, which

assures complete embedding of GNPs in polymer matrix

preventing filler leaching, is studied in this work as a

green method for production of PLA/GNPs composites.

Materials and Methods PLA 2003D, was purchased from Natureworks.

Graphene-nanoplatelets, grade C750 (GNP-C) and M-5

(GNP-M) were acquired from XG Sciences. PLA/GNP-M

and C 0.25 wt.% composites were prepared by melt

blending in a Thermo Haake Polylab (180 °C, 15 min, 25

rpm), and moulded in a hot press (190 ºC, 2 minutes)

into thin sheets (0.3-0.5 mm). Samples were immersed

in 50 mL PBS in sterile conditions and incubated for 6

months (37 °C, 100 rpm). X-Ray diffraction (XRD)

analysis, was performed using a Philips X´Pert

diffractometer. Tensile properties of the composites

(60x15 mm) were measured (Mecmesin Multitest-1d,

Mecmesin BF 1000N) at room temperature and strain

rate of 10 mm min-1

. Dynamical mechanical analysis

(DMA) was performed using a DMA 242 E Artemis

(Netzsch) in tension assays (6N, 10 minutes) with 10

minutes recovery. Biocompatibility of materials was

evaluated using HFF-1 cells cultured at the surface of

PLA, PLA/GNP-M and C 0.25 wt.% films (Ø = 5.5 mm)

and in direct contact with materials extracts obtained

after 6 months incubation in PBS (50 µL in 150 µL

DMEM+, after 24h cell grow). In both assays cells were

seeded in 96 well plates (7500 cells per well) and 20 µL

resazurin solution added at 24, 48, and 72h and

incubated for 3h, fluorescence (λex/em=530/590 nm)

read and metabolic activity evaluated (Metabolic

activity (%) = Fsample/FPLA x 100). Suitable controls were

performed for both biocompatibility assays.

Results and discussion XRD GNP-M and C powders present similar XRD spectra,

typical of carbon materials, with an intense peak around

31°, and two broad peaks around 50° and 65°. PLA,

before (0M) and after 6 months (6M) biodegradation,

presents similar spectra with two broad peaks, the first,

around 20°, is more intense than the second, around

35°. PLA/GNP-M 0.25 wt.% 0 and 6M present similar

spectra, with PLA and GNP-M peaks being observed,

which confirms the filler presence in polymer matrix.

For PLA/GNP-C 0.25 wt.% 0M and 6M spectra are also


similar, however GNP-C peak is less intense than GNP-M

peak.

Tensile tests Incorporation of GNP-C and M in PLA increased its

Young´s modulus by 14 %. Also, tensile strength is

increased by 20% with GNP-C incorporation and by 6%

with GNP-M. Improvements in toughness of 20% are

only observed for GNP-C. After 6 months

biodegradation no significant changes are observed in

Young´s modulus for all materials tested. Decreases in

tensile strength, elongation at break, and toughness are

respectively, for PLA of 2.6, 2.5, and 10 fold, for

GNP/PLA-M of 1.6, 1.8 and 3.3 fold, and for GNP-C of

1.4, 1.4 and 1.7 fold. Thus, the presence of the fillers

prevents decreases of PLA mechanical properties with

biodegradation, namely tensile strength, elongation at

break and toughness. Also, GNP-C incorporation seems

to have a more beneficial effect than GNP-M, especially

in toughness.

DMA Figure 1 shows that for PLA, dLf (final, at 6N) after 10

cycles before degradation was of 14.2 µm, being of 13.7

and 13.2 µm for PLA/GNP-M and C 0.25 wt.%,

respectively. After 6 months degradation, PLA sample

ruptured after 4 cycles (1.A) reaching a dLf of 56.3 µm,

PLA/GNP-M and C 0.25 wt.% did not ruptured (1.B,C)

and presented a slight increase in dLf, which were of

16.8 and 16.7 µm, respectively.

These results are in agreement with those obtained in

tensile tests, with a significant decay in PLA mechanical

properties after 6 months biodegradation and small

effects observed for PLA/GNP-M and C 0.25 wt.%. Thus,

fillers are reinforcing the polymer matrix and retarding

decrease of its mechanical properties. Materials

degradation was confirmed by GPC-SEC and SEM (results

not shown).

Cell adhesion and proliferation assays HFF-1 cell metabolic activity at PLA surface was 75% at

24 and 48h, and 94% at 72h, comparing with cells at

tissue culture treated surface of 96 well plates.

PLA/GNP-M and C 0.25 wt.%, metabolic activity never

decreased below 90%, for both composites in

comparison with PLA. Thus, fillers incorporation has no

impact in cell adhesion and proliferation at materials

surface.

Degradation products cytotoxicity A control performed with PBS (37 ºC, 100 rpm, 6

months) presented similar cell metabolic activity (24,

48, 72h) to PLA 6M degradation products, which shows

that they are not toxic. Figure 2 shows that degradation

products of PLA/GNP-M and C 0.25 wt.% 6M are not

toxic (24, 48, 72h), comparing with PLA 6M, according

to ISO 10993-5:2009(E), which considers toxic a material

that decreases cell viability below 70% of negative

control for cell viability. Also, cell morphology is normal

and similar for all conditions tested (images not shown).

Conclusions GNP-M and GNP-C incorporation in PLA matrix at low

loadings (0.25 wt.%) improved mechanical properties

and decreased their decay until 6 months

biodegradation. These nano-fillers can be used to tune

PLA mechanical performance during biodegradation.

PLA/GNP-M and C composites allow similar HFF-1 cell

adhesion and proliferation at the surface and do not

release toxic products.

R e f e r e n c e s

[1] Kim K, Abdala A and Macosko W, Macromolecules,

43 (2010) 6515.

[2] Lahiri D, Rupak D, Cheng Z, Socarraz-Novoa I, Bhat

A, Ramaswamy S, Agarwal A, ACS Appl. Mater.

Interfaces, 4 (2012) 2234.

[3] Pinto AM, Moreira S, Gonçalves IC, Gama FM,

Mendes AM, Magalhães FD., 2013.

Biocompatibility of poly(lactic acid) with

incorporated graphene-based materials, Colloids

Surf B Biointerfaces, 104 (2013) 229.

[4] Pinto AM, Cabral J, Tanaka DA, Mendes AM,

Magalhães FD, Effect of incorporation of graphene

oxide and graphene nanoplatelets on mechanical

and gas permeability properties of poly(lactic acid)

films, Polymer International, 62 (2013) 33.

[5] Pinto AM, Gonçalves IC, Magalhães FD, Colloids

and Surf B Biointerfaces, 111 (2013) 188.

F i g u r e s

Figure 1: Multi cycle DMA of PLA and composites before and after 6

months degradation.

Figure 2: Cytotoxicity of PLA/GNP-M and C 0.25 wt.% 6 months

degradation products, comparing with PLA in the same conditions.

Assays were performed in triplicate, with 6 replicates for each

condition tested. Error bars represent standard deviation. Red line

represents cytotoxicity limit of 70%.


V. Morin, S. Bauerdick, P. Mazarov, L.

Bruchhaus, R. Jede

Raith GmbH, Dortmund, Germany

[email protected]

I o n C o l u m n a n d S o u r c e

t e c h n o l o g y e m p l o y i n g G a l l i u m

a n d N e w I o n S p e c i e s f o r

A d v a n c e d F I B N a n o f a b r i c a t i o n

An increasing number of applications use focused

ion beam (FIB) systems for nanofabrication and

rapid prototyping tasks. FIB nanofabrication is a

good partner to other lithography techniques

providing complementary strengths like direct,

resistless, and three-dimensional patterning.

Although a FIB process can in many cases be slower

than a resist-accelerated process, the relative

simplification of the overall nanofabrication

approach, especially for the direct processing of

novel materials, helps to achieve scientific results

faster. We report on our continuous effort to

advance FIB technology along with an

instrumentation platform dedicated to

nanofabrication requirements.

The nanofabrication requirements for FIB

technology are specific and more demanding in

terms of stability, resolution, and the support of new

processing techniques. To advance nanofabrication

applications, we have improved gallium-based liquid

metal ion source (LMIS) with a stable gun emission

design enabling long-term stability without the need

for frequent heating, and producing low drifts in

probe current (Figure 1) and beam position.

Moreover, we report a FIB spot allowing excellent

patterning resolution with low collateral damage.

This spot is usually not a pure Gaussian distribution,

instead exhibiting significant beam tails, which have

to be as small as possible for high resolution

nanofabrication. In order to measure the beam

current distribution we employed a method based

on the amorphization of single crystal silicon by

Gallium ions.

Compared with conventional LMIS FIB, the results

here show a very narrow and large central Gaussian

part and very low tails. As the most relevant part for

milling is in the dose range of 1 to 10-3

, this

technology offers superior performance especially

for nanofabrication. Combining this FIB technology

with an instrumentation platform optimized for

nanometer scale patterning over large areas and

extended periods of time applications such as X-ray

zone plates [1], large area gratings [2], plasmonic

arrays, and wafer-scale nanopore devices become

possible.

Moreover the type of ion defines the nature of the

interaction mechanism with the sample and thus

has significant consequences on the resulting

nanostructures. Therefore, we have extended the

technology towards the stable delivery of multiple

ion species selectable into a nanometer-scale

focused ion beam by employing a liquid metal alloy

ion source (LMAIS). A mass separation filter is

incorporated into the column to allow for fast and

easy switching between different ions or clusters

within less than a minute [3,4,5]. This provides single

and multiple charged species of different mass

(Figure 2), e.g. Be, Si, Ge or Au, resulting in

significantly different interaction mechanisms. We

present and discuss the capabilities of the

instrument for sub-20 nm to sub-10 nm

nanofabrication (Figure 3) as well as potential

applications. Using a Si ion beam for high resolution

low contamination milling or a Au ion beam for

surface functionalization will be given as examples

for a full range of techniques yet to be explored.

R e f e r e n c e s

[1] A. Nadzeyka et al., Microelectr. Engineering 98

(2012), 198-201.

[2] S. K. Tripathi et al., J. Micromech. Microeng. 22

(2012) 055005.

[3] B. R. Appleton et al., Nucl. Instrum. Methods B

272, 153 (2012).

[4] S. Tongay et al., Appl. Phys. Lett. 100, 073501

(2012).

[5] S. Bauerdick et al., JVST B 31 (2013) 06F404.


F i g u r e s

Figure 1: Probe current

measurement of a Ga ion source over 67 hours

0 100 200 300 400

0

100

200

300

400

500

600

700

800

900

1000

1100

Si++

Si+

Au++

Au+

Au+

2

current (pA)

mass (amu)

Au++

3

Figure 2: Mass spectrum of a AuSi ion source with various ion

species.

Figure 3: Results for milling of a 40 nm gold layer on a bulk sample: 7

nm to 19 nm features obtained with a Be, Si and Au ion beam (from

left to right) [5].


Ana I. S. Neves1,2, Luis V. Melo

1,3, Saverio

Russo1, Isabel de Schrijver

4, Helena Alves

1,5,

Monica F. Craciun1

1 Centre for Graphene Science, College of Engineering,

Mathematics and Physical Sciences, Univ. of Exeter, UK 2 INESC – Microsystems and Nanotechnology, Portugal

3 Physics Department, Instituto Superior Técnico,

University of Lisbon, , Portugal 4 CenTexBel – Belgian Textile Research Centre, Belgium.

5 CICECO – Centre for Research in Ceramics and

Composite Materials, University of Aveiro, Portugal

[email protected]

G r a p h e n e - c o a t e d t r a n s p a r e n t

c o n d u c t i n g f i b r e s f o r s m a r t

t e x t i l e s

The development of electronic textiles is one of

the hottest topics in organic electronics. There are

already examples of smart textiles in garments for

monitoring physiological and biomechanical

signals. However, the manufacturing schemes for

current applications rely mostly on the integration

of off-the-shelf electronic components mounted

on a textile substrate. Such components are

silicon-based, thus unsuitable for applications

where flexibility and fault-tolerance are required.

Organic electronics is an alternative to

conventional silicon technology and can overcome

those limitations. In this sense, graphene, with

high optical transparency and electrical

conductivity, is a promising material.

In the pursuit of conducting fibres, our approach

consisted in coating specially designed

nanosmooth polypropylene fibres with graphene.

Monolayer graphene was grown on copper foils by

low pressure chemical vapour deposition using

methane as a carbon source, and wet-transferred

to the fibres after copper etching. Graphene

adhesion to the fibres was found to be sensitive to

minute surface modifications. In that sense,

several surface treatments were tested and AFM

microscopy was performed to evaluate the

resulting changes in the surface of the fibres.

Raman spectroscopy confirmed the presence and

quality of the graphene transferred onto the

fibres, and optical measurements proved that the

fibres remained transparent after the graphene

coating. The I-V response of the fibres was

measured with different curvatures, and the

corresponding sheet resistance was found to be of

the same order than monolayer graphene on

conventional silicon substrates, up to 104 Ω/sq.

Besides polypropylene, the study was successfully

extended to Nylon commercial fibres.

F i g u r e s

Figure 1: Graphene-coated polypropylene fire closing an electric

circuit that is powering a LED (graphite was applied to define the

channel area).


Jana B. Nieder

INL - Internatioanl Iberian Nanotechnology Laboratory,

Braga, Portugal

[email protected]

P r e s e n t a t i o n o f t h e N e w

“ U l t r a f a s t B i o - a n d

N a n o p h o t o n i c s ” L a b o r a t o r y a t

I N L

A new laboratory devoted to light-matter

interaction on the nanoscale is being set up at INL

International Iberian Nanotechnology Laboratory.

We are going to present the different techniques,

which are being implemented and developed to

allow optical and magneto-optical sensitivities

reaching into femtosecond and nanometer scales.

Fluorescence (lifetime) spectroscopy will be

available to study e.g. the sensitivity of plasmonic

biosensors. To obtain spatially resolved information

of nanostructured material or biological samples,

several imaging techniques, one of them reaching

below the optical diffraction limit, are going to be

implemented. To obtain 3D super-resolution

sensitivity a concept developed last year by Chizhik

et al. [1], based on the interaction of fluorophores

with a thin metal film, shall be set up and further

developed to allow for 3D multicolor life cell

imaging.

Taking advantage of the available femtosecond

laser, several techniques based on nonlinear

interaction effects, such as multi-photon

microscopy and 3D laser lithography will be made

available.

For increased imaging contrast in multi-photon

microscopy the pulse characteristics will be

optimized, e.g. using supercontinuum generation in

photonic crystal fibers (in collaboration with U Porto).

Optically detected magnetic resonance ODMR on

color centers in nanodiamonds shall be used to

develop a magnetometry technique with nanoscale

sensitivity, e.g. to precisely characterize magnetic

fields around ferromagnetic nanostructures or

biological material, e.g. neurons.

R e f e r e n c e s

[1] “Metal-Induced Energy Transfer for Live Cell

Nanoscopy“, A. I. Chizhik, J. Rother, I. Gregor, A.

Janshoff, J. Enderlein, Nature Photonics 8, 124–

127 (2014)

F i g u r e s

Figure 1: Visualization of techniques available and to be developed

in the “Ultrafast Bio- and Nanophotonics” laboratory at INL-

International Iberian Nanotechnology Laboratory.


Giovanni Onida, Nicola Manini, Nicola Ferri,

Ivano Castelli

Dipartimento di Fisica, Via Celoria 16, 20133 Milano, Italy

[email protected]

C a r b o n s p w i r e s a n d t h e i r

c o u p l i n g t o g r a p h e n e

Carbon monoatomic wires, known as carbynes,

have recently emerged as a novel form of

nanostructured carbon which can be routinely

synthesized [1] We present, as an evident

demonstration of how far material properties can

be changed by barely "nanostructuring" it, a series

of theoretical and computational results about the

mechanical, electronic, magnetic and vibrational

properties of nanostructures based on sp-

hybridized carbon [2-6]. We illustrate several

implications for possible applications, including

nanoelectronics, spintronics, and nano-sensing.

R e f e r e n c e s

[1] E. Kano, A. Hashimoto, M. Takeguchi,

Microscopy and Microanalisys 20 (2014) 1742;

E. Erdogan, I. Popov, C. G. Rocha, G. Cuniberti,

S. Roche, and G. Seifert, Phys. Rev. B 83, (2011)

041401; C.Jin, H. Lan, L. Peng, K. Suenaga, and

S. Iijima, Phys. Rev. Lett. 102 (2009) 205501; A.

Chuvilin, J. C Meyer, G. Algara-Siller and U.

Kaiser, New J. Phys. 11 (2009) 083019;

[2] E. Cinquanta, N. Manini, L. Ravagnan L.

Caramella, G. Onida, P. Milani, and P. Rudolf, J.

Chem. Phys. 140 (2014) 244798.

[3] T.M. Mazzolari and N. Manini, J. Phys.: Condens.

Matter 26 (2014) 215302.

[4] I.E. Castelli, N. Ferri, G. Onida, and N. Manini, J.

Phys.: Condens. Matter 24 (2012) 104019.

[5] I.E. Castelli, P. Salvestrini, and N. Manini, Phys.

Rev. B. 85 (2012) 214110.

[6] Zeila Zanolli, Giovanni Onida, and J.-C. Charlier,

ACS Nano 4 (2010) 5174.

[7] L. Ravagnan, N. Manini, E. Cinquanta, G. Onida,

et al., Phys. Rev. Lett. 102 (2009) 245502.

F i g u r e s

Figure 1: Some systems realized by carbon monoatomic wires, and

their coupling to sp2 carbon: i) Structural snapshot from finite-

temperature TBMD simulation; ii) example of a localized on-chain

electronic state; iii) electronic structure showing π-state magnetism.


M. J. Pereira, J. S. Amaral, N. J. O. Silva and

V. S. Amaral

Departamento de Física and CICECO, Universidade de

Aveiro, Aveiro, Portugal

[email protected]

S c a n n i n g T h e r m a l M i c r o s c o p y :

u n r a v e l i n g a n d m a p p i n g

t h e r m a l p h e n o m e n a a t t h e

n a n o s c a l e

There has been growing interest in obtaining greater

knowledge on heat transport phenomena in

nanostructured materials, since they are often

determinant for the performance of modern micro

and nano-devices, such as sensors possessing nano-

sized features and thermoelectric nanomaterials.

Furthermore, nanoscale thermal properties assume

great relevance in modern electronic circuits that

dissipate power at the nanoscale.[1] Scanning

thermal microscopy (SThM) is a powerful tool with a

leading role concerning probing and mapping of

local thermal properties of materials and heat

generation with nanometric spatial resolution.

Based on an atomic force microscope (AFM), the

SThM uses a specialized heated thermal probe

designed to act as a thermometer instead of the

conventional AFM tip. Since its invention, AFM

revealed itself a fundamental mean for imaging and

introducing features at the nanoscale that alter the

structure and properties of the materials. Enabling

self-heating on a conventional AFM tip paved the

way for its implementation, in the form of Scanning

Thermal Microscopy, not only in a wide variety of

manufacturing and imaging applications with

unmatched quality, but also as a leading technique

in the search for thermal functional properties.

Determining and acting on the thermo-physical

properties of microstructures is thus of great use in

understanding/modelling heat transfer and

macroscopic properties of heterogeneous materials.

As an example, the study of contrast thermal

properties is especially important for the study of

polymer composites and lithographed materials.

The fundamental feature of this technique, the

SThM tip, is a nanofabricated thermal probe that

can act as a resistance thermometer or a resistive

heater, depending on the selected operation mode:

passive mode or active mode, also known as

temperature contrast mode (TCM) and (thermal)

conductivity contrast mode (CCM), respectively. It is

also possible to collect simultaneously surface

topography image and thermal image of the

samples under analysis due to the independent

nature of both AFM and SThM mechanisms in the

same equipment (fig. 1).

Here we present exploration routes for the study of

phenomena by Scanning Thermal Microscopy. Using

a XE7 Scanning Probe Microscope with Scanning

Thermal Microscopy from Park Systems [2], in this

presentation we show the path for research in

relevant topics, namely thermal conductivity of

graphene layers deposited on different substrates

by conductivity contrast, the electrocaloric or

magnetocaloric effects in nanostructured materials.

Further work on inducing and studying structural

phase transformations on thin films of functional

materials with relevant properties for application in

nano-devices, such as BaTiO3 and Ni2MnGa is also

presented. Work in progress for this technique

includes also its application to time dependent

processes, bringing it forward as a contribution to

otherwise complex analysis of dynamic processes.

Due to its high thermal conductivity and subsequent

efficiency in heat conduction, graphene is noted as

suitable candidate to aid overcome the obstacle of

increasing dissipation power density arising from

constant downscaling of electronic devices. In fact,

graphene’s excellent thermal properties, combined

with highly interesting electronic and optical

properties, recommend it for a wide range of

applications in several fields. [3.] However, the

mechanisms behind graphene’s thermal properties

still lack clarity. It has been shown that graphene

monolayers possess high thermal conductivity, but

the values obtained so far seem to vary according to

the deposition method and measurement

technique. SThM presents itself as a reliable

technique to clarify the intriguing thermal properties

of graphene monolayers (fig. 2), namely by enabling

accurate estimation of the thermal conductivity of

this material supported by different substrates,

relying on thermal contrast between the graphene

monolayer and other materials with known thermal

conductivity [4].

The electrocaloric (EC) effect consists in the

variation of temperature that some materials


experience under an applied electric field, which is

enhanced at temperatures near ferroelectric phase

transitions. [5] This is why EC is becoming an

interesting alternative to refrigeration based on the

magnetocaloric effect due to the economically

inviable large magnetic fields that this effect

requires. [6][7] Thin films exhibit especially high EC

effects. However, direct measuring of EC in thin

films is hard to accomplish due to the great

difference between heat flow output shown by thin

film and substrate. SThM solves this inconvenience,

allowing direct measurement mapping of

temperature changes in several spots of a thin film,

enabling and promoting thus the search for

promising materials for micro-scale cooling

applications.


This work is funded by FEDER through “Programa

Operacional Factores de Competitividade” - COMPETE and

by national funds through FCT - Fundação para a Ciência e

Tecnologia with the projects HEAT@UA RECI/CTM-

CER/0336/2012 and PEst-C/CTM/LA0011/2013 (FCOMP-01-

0124-FEDER-037271)

R e f e r e n c e s [1] Volz, Sebastian, Rémi Carminati, Microscale and

Nanoscale Heat Transfer, Berlin Springer (2007)

181-236

[2] http://www.parkafm.com

[3] Alexander A. Balandin, Suchismita Ghosh,

Wenzhong Bao, Irene Calizo, Desalegne

Teweldebrhan, Feng Miao, Chun Ning Lau, Nano

Lett., 8 (2008) 902–907

[4] Anton N. Sidorov, Daniel K. Benjamin,

Christopher Foy, Appl. Phys. Lett., 103 (2013)

243103

[5] S. Kar-Narayan, S. Crossley, X. Moya, V.

Kovacova, J. Abergel, A. Bontempi, N. Baier, E.

Defay, N. D. Mathur, Appl. Phys. Lett., 102

(2013) 032903

[6] Dongzhi Guo, Jinsheng Gao, Ying-Ju Yu, Suresh

Santhanam, Gary K. Fedder, Alan J. H.

McGaughey, S. C. Yao, Appl. Phys. Lett., 105

(2014) 031906

[7] Xavier Moya, Enric Stern-Taulats, Sam Crossley,

David González-Alonso, Sohini Kar-Narayan,

Antoni Planes, Lluís Mañosa, Neil D. Mathur,

Advanced Materials, 25 (2013) 1360–1365

F i g u r e s

Figure 1: Schematic showing the independent nature of

both mechanisms for topographical and thermal images

collection (adapted from Park Systems [2])

Figure 2: Left: topographical image of

Si/graphene interfaces performed with

thermal nanoprobe of SThM system;

Right: SThM conductivity contrast image

(CCM) of the area depicted on the left

and line profile showing the contrast in

thermal conductivity between graphene

and Si


Jimena A. Olmos-Asar1, Erik Vesselli

2,3,

Alfonso Baldereschi1 and Maria Peressi1,4

1Physics Department, University of Trieste, Trieste, Italy

2Physics Department and CENMAT, University of Trieste,

Trieste, Italy 3IOM-CNR Laboratorio TASC, Trieste, Italy

4IOM-CNR DEMOCRITOS, Trieste, Italy

[email protected]

S e e d i n g , n u c l e a t i o n a n d

r e a c t i v i t y o f

a l u m i n a / N i 3 A l ( 1 1 1 ) s u p p o r t e d

m e t a l l i c n a n o c l u s t e r s :

a n a b - i n i t i o i n v e s t i g a t i o n

We investigate the mechanisms of seeding and

nucleation of metallic nanoclusters onto an ultrathin

alumina template supported on Ni3Al(111) (Figure

1a,b) by means of ab-initio density functional theory

calculations. Many atoms (Fe, Co, Ni, Cu, Pd, Ag and

Au) show preferential occupation of the defective

sites of the ordered so-called “dot” structure of the

oxide film (Figure 1c), where the adsorption is

stronger than in the “network” or any other surface

site. The relative strength varies with the atomic

species, going from the large values of Pd and Ni to

the low value of Ag. These results rationalize the

experimental evidence showing that some metals

such as Pd and Ni create highly ordered patterns of

seeds and further nucleation of nanoclusters (Figure

2), whereas others, such as Ag, give rise to less

ordered superstructures at room temperature [1].

We study then the interaction of carbon monoxide

with a self-seeded ordered array of Cu nanoclusters,

comparing simulations with in situ X-Ray

Photoelectron Spectroscopy measurements.

Adsorption and dissociation of carbon monoxide

occur at the copper clusters. The involved

mechanisms are investigated at the atomic level,

unveiling the effects of cluster finite size,

reconstruction, support, and of local CO coverage. It

is found that the high coverage of CO at the cluster

surface, which considerably exceeds that achievable

on single crystal surfaces, facilitates the metal

restructuring and the reaction, yielding carbon

incorporation into the bulk of the particles (Figure 3)

[2,3].

R e f e r e n c e s

[1] J. A. Olmos-Asar, E. Vesselli, A. Baldereschi and M.

Peressi, in preparation

[2] J. A. Olmos-Asar, E. Vesselli, A. Baldereschi, and M.

Peressi, Self-seeded nucleation of Cu nanoclusters

on Al2O3/Ni3Al(111): an ab-initio investigation,

Physical Chemistry Chemical Physics 16 (2014)

23134-23142.

[3] J. A. Olmos-Asar, E. Monachino, C. Dri, A. Peronio,

C. Africh, P. Lacovig, G. Comelli, A. Baldereschi, M.

Peressi, and E. Vesselli, CO on supported Cu

nanoclusters: coverage and finite size contribu-

tions to the formation of carbide via the

Boudouard process, submitted

F i g u r e s

Figure 1: a) Top view of the structural model of the Al2O3/Ni3Al(111)

(O: red; Al: green; Ni: blue); the white circle around the “dot” defect

highlights a reduced model considered for calculations. b) The

periodically repeated unit cell. c) Top and side view of the equilibrium

configurations for a monoatomic Cu seed in the “dot” defect.

Figure 2: Side view of the

equilibrium configurations for a

15-atom Cu nanocluster

nucleated in the “dot” defect of

alumina/Ni3Al film.

Figure 3: A small Cu unsupported nanocluster covered by CO

molecules and a possible resulting configuration after reaction of

two molecules.


M.J. Perez-Roldan1, F. Tatti

2, A. Berger

1,

A. Chuvilin1,3

1CIC nanoGUNE Consolider, Donostia-San Sebastian,

Spain. 2FEI Electron Optics Eindhoven, The Netherlands.

3Ikerbasque, Basque Foundation for Science, Bilbao,

Spain

[email protected]

O n e s t e p F E B I D f a b r i c a t i o n o f

C o b a s e d m a g n e t i c n a n o t u b e s

Focused electron beam induced deposition (FEBID)

is a well-known direct-writing technique that has

been widely studied in the last decades due to its

versatility as micro and nanofabrication tool [1, 2].

Most recently, the deposition in parallel of two

different precursors has also called the attention of

several researchers in order to grow binary alloys [3-

6]. In these alloys the relative flux of the two

precursors was varied in order to tune the bulk

composition and confer to the deposits different

electric and magnetic properties.

In this work, binary systems of Co-SiOx in a

carbonaceous matrix has been deposited using

dicobalt octacarbonyl (Co2(CO)8) and tetraethyl

orthosilicate (Si(OC2H5)4) precursors. Planar cross-

sections of deposited pillars were prepared and the

composition distribution was investigated by energy

dispersive X-ray spectroscopy (EDX) maps. Magnetic

characterization was performed by Lorentz

microscopy.

Results showed a non-homogeneously distributed

composition inside the FEBID pillars but a symmetric

radial distribution, as can be seen in Figure 1a)

where the EDX map of the cobalt element in

showed. Moreover, Lorentz microscopy showed a

magnetic behaviour localized on the areas with the

highest cobalt content, see Figure 1b).

Hence, we report in this work a single step

nanofabrication process of magnetic nanotubes.

R e f e r e n c e s

[1] Huth, M., et al., Beilstein J. Nanotechnol. 3,

597–619, (2012).

[2] Utke, I., et al., J. Vac. Sci. Technol. B 26, 1197,

(2008).

[3] Porrati, F., et al., Nanotechnology. 23, 185702,

(2012).

[4] Porrati, F., et al., J. Appl. Phys. 113, 053707,

(2013).

[5] Winhold, M., et al., ACS Nano. 5, 9675, (2011).

[6] Che, R.C., et al., Appl. Phys. Lett. 87, 223109,

(2005).

F i g u r e s

Figure 1: a) EDX map of Cobalt distribution on the pillar and b) contour

lines showing themagnetic flux distribution in the pillar.


Joana Fontes Queiroz, Ana Rute Neves, Sofia

A.Costa Lima and Salette Reis

REQUIMTE, Department of Chemical Sciences, Faculty of

Pharmacy, University of Porto, Porto, Portuga

[email protected]

N e w i n s i g h t s i n t h e

d e v e l o p m e n t o f s o l i d l i p i d

n a n o p a r t i c l e s f o r a c t i v e

b r a i n - t a r g e t e d d r u g d e l i v e r y

The challenging of cross the blood-brain barrier

(BBB) and reach the brain in an appropriated

therapeutic concentration is the Holy Grail for

effectively treat and cure brain diseases. The BBB is

not only a physical barrier, it constitutes a dynamic,

semi permeable and highly selective barrier that

protects and supplies the brain. However the BBB

represents a considerable obstacle to brain entry of

the majority of drugs and thus severely restricts the

therapy of many brain diseases including brain

tumors, brain HIV, Alzheimer and other

neurodegenerative diseases. The traditional drug

delivery systems with no brain targets release the

drugs in systemic circulation failing the delivery into

the brain. Therefore, there is a huge need to

develop and design approaches with specific target

to brain in a better and more effective way for the

treatment of brain diseases. Here, the

nanotechnology can be an important tool to

improve the specificity and permeability of drugs in

the BBB [1].

In this work we developed a new delivery system to

direct drugs to the brain, by functionalizing solid

lipid nanoparticles (SLNs) with apolipoprotein E (Apo

E), aiming to enhance their binding to low-density

lipoprotein (LDL) receptors overexpressed on the

BBB endothelial cells.

SLNs were successfully functionalized with Apo E,

using two distinct strategies which took advantage

of the strong interaction between biotin and avidin.

The functionalization of SLNs with ApoE was

demonstrated by infrared spectra and fluorimetric

assays. Transmission electron microscopy (TEM)

images revealed spherical nanoparticles, dynamic

light scattering (DLS) gave a Z-average under 200

nm, polydispersity index below 0.2 and zeta

potential between -10 mV and -15 mV. A stability

study revealed that these characteristics remained

unchanged for at least 6 months. In vitro cytotoxic

effects were evaluated by MTT and LDH assays in

the hCMEC/D3 cell line, a human BBB model, and

revealed no toxicity up to 1.5 mg/ml for 4 hour of

incubation. The BBB permeability was also evaluated

in transwell devices with hCMEC/D3 monolayers and

it was found a 1.5-fold increase in the permeability

of functionalized SLNs when compared with non-

functionalized ones.

In order to clarify the transport pathways of the

nanoparticles through the BBB, the different

molecular mechanisms of endocytosis and

transcytosis processes were carefully studied using

flow cytometry system (FCS), confocal laser scanning

microscopy (CLSM) and fluorimetric assays with

tracers and different pathway inhibitors. The

transport of SLNs across the hCMEC/D3 monolayer

was found through a transcellular but not a

paracellular route. Functionalized SLNs exhibited

higher intracellular uptake compared with non-

functionalized ones and were found to enter the

cells through a specific clathrin-mediated

mechanism, related to the expression of LDL

receptors on BBB. The results suggested that these

novels ApoE-functionalized SLNs resulted in dynamic

stable systems capable of being used for an

improved and specific brain delivery of drugs

through the BBB.

A c k n o w l e d g m e n t s

ARN acknowledges the FCT for financial support

through the Ph.D. grant (SFRH/BD/73379/2010). The

authors are greatly indebted to financing sources of

EU through the Project ON2, NORTE-07-0124-

FEDER-000067 and from FCT through the project

Pest-C/EQB/LA0006/2013.

R e f e r e n c e s

[1] Kaur I. P.; et al., Journal of Controlled Release.

Potential of solid lipid nanoparticles in brain

targeting (2008) 127, 97-109.


Sohel Rana1, Shama Parveen

1, Raul

Fangueiro1, Maria Conceição Paiva

1, José

Xavier2

1University of Minho, Campus de Azurem, Guimaraes,

Portugal 2INEGI, FEUP, University of Porto, Porto, Portugal

[email protected]

D e v e l o p m e n t o f D u c t i l e

C e m e n t i t i o u s C o m p o s i t e s

U s i n g C a r b o n N a n o t u b e s

Concrete is the primary construction material for

civil infrastructures and generally consists of

cement, coarse aggregates, sand, admixtures and

water. Cementitious materials are characterized by

quasi-brittle behaviour and susceptible to cracking

[1]. The cracking process within concrete begins

with isolated nano-cracks, which then conjoin to

form micro-cracks and in turn macro-cracks.

Formation and growth of cracks lead to loss of

mechanical performance with time and also make

concrete accessible to water and other degrading

agents such as CO2, chlorides, sulfates, etc. leading

to strength loss and corrosion of steel rebars. To

improve brittleness of concrete, reinforcements

such as polymeric as well as glass and carbon fibers

have been used and microfibers improved the

mechanical properties significantly by delaying

(but could not stop) the transformation of micro-

cracks into macro forms [2]. This fact encouraged

the use of nano-sized fillers in concrete to prevent

the growth of nano-cracks transforming in to micro

and macro forms. Nanoparticles like SiO2, Fe2O3,

and TiO2 led to considerable improvement in

mechanical performance and moreover, nano-TiO2

helped to remove organic pollutants from concrete

surfaces [3].

Nanomaterials with exceptional properties like

carbon nanotube (CNT) [4] have been incorporated

within cementitious matrix to improve mechanical

performance and toughness and to introduce

electrical conductivity and piezoresistivity [1].

Additionally, in nano-scale, CNTs exhibited the

possibility to restrict the growth of nano-cracks

through crack-bridging mechanism, thereby,

enhancing the durability of concrete. However,

the improvement of above properties was found

strongly dependant on the dispersion of CNT

within cementitious matrix and improper

dispersion and agglomeration even resulted in

deterioration of various properties. Therefore,

there exists an enormous need for an efficient

dispersion route to achieve homogeneous CNT

dispersion and besides mechanical treatments

(ultrasonication, stirring), various chemical

dispersants (surfactants and polymers) have been

suggested to prepare well dispersed CNT aqueous

suspensions for mixing with cement [1].

The present paper reports the use of a novel

dispersant (Pluronic F-127) to disperse CNTs in

water and subsequently within cementitious

matrix and the fracture behaviour of the resulting

cementitious composites. CNT/water suspensions

with different CNT concentrations were prepared

using a short ultrasonication process (1 hr) with

the help of Pluronic F-127 at optimum

concentrations, and the suspensions were then

mixed with cement/sand mixture to develop

cementitious composites. The fracture behaviour

was studied using single-end notched bending

(SENB) specimens in the 3 point bend

configuration and measuring the crack

propagation parameters (such as crack length,

crack-tip opening displacements, etc.) using digital

image correlation technique (DIC). Fracture energy

and toughness were then calculated using these

parameters.

The load-displacement curves of plain mortar and

CNT/mortar samples are presented in Figure 1. It is

very clear from these graphs that the samples

containing CNTs showed significantly higher

breaking strain and ductility as compared to plain

mortar specimens. The cementitious composites

containing 0.1 wt. % single walled nanotubes

(SWNTs) and 0.15 wt. % multi-walled nanotubes

(MWNTs) resulted in 109% and 96% improvements

in the fracture energy of plain mortar specimens,

respectively. Fracture surface study using Scanning

Electron Microscopy (SEM) suggested that CNTs


were tightly inserted between the hydration

products of cement and showed bridging of cracks

to prevent quick propagation of cracks and

opening of crack mouth, resulting in higher

fracture energy and ductility.

R e f e r e n c e s

[1] Parveen S, Rana S, Fangueiro R, Journal of

Nanomaterials, 2013 (2013) 1-19.

[2] Akkaya Y, Shah SP, Ghandehari M, ACI Special

Publications, SP 216 (2003) 1-18.

[3] Qing Y, Zenan Z, Deyu K, Construction and

Building Materials, 21 (2007) 539-545.

[4] Rana, S, Alagirusamy R, Joshi M, Journal of

Reinforced Plastics and Composites, 28 (2008)

461-487.

F i g u r e s

Figure 1: Load-displacement curves of notched samples of plain mortar and CNT/mortar composites, tested at 3 point bending configuration


Cláudia D. Raposo1,2, Krasimira T.

Petrova2, M. Margarida Cardoso

2

1IBET, Av. República, Quinta do Marquês Estação

Agronómica Nacional, Oeiras, Portugal 2REQUIMTE, CQFB, Departamento de Química,

Faculdade de Ciências e Tecnologia, Universidade Nova

de Lisboa, Caparica, Portugal

[email protected]

S y n t h e s i s o f n o v e l

g a l a c t o s e - P L G A n a n o p a r t i c l e s

c o n t a i n i n g d o x o r u b i c i n f o r

h e p a t o c y t e t a r g e t i n g

One of the major goals within cancer therapies is to

increase drug concentration in the tumor, decrease

the systemic dose and, at the same time, attack only

cancer cells. Drug delivery systems able to target

specific cells/tissues due to recognition processes

could be one of the solutions. These systems can

therefore increase the drug at the active site,

decrease therapeutic quantities, increase efficiency

and reduce toxicity [1].

To treat liver diseases, it is possible to synthetize

galactose conjugates for specific recognition by the

asialoglycoprotein receptor (ASGPR) in hepatocytes.

ASGPR recognizes terminal galactose or N-

acetylgalactosamine residues, which makes ASGPR a

potential target to the liver [2]. Our study is focused

on the synthesis of di-galactose compounds to

evaluate their interaction with ASGPR in order to

use these ligand as a hepatocyte recognition unit.

These compounds will be covalently attached to a

biocompatible polymer [3] that will be used to

produce nanoparticles containing an encapsulated

drug. The produced nanoparticles should have an

amphiphilic structure that allows the drug capture in

the hydrophobic center (biopolymer part) whilst the

outside of the nanoparticle is hydrophilic, with

galactose residues for the ASGPR.

Under this context, we present the synthesis of a di-

galactose-PLGA conjugate that is subsequently used

to prepare nanoparticles containing doxorubicin.

The produced nanoparticles are characterized in

terms of morphology and size, drug release profile

and cellular recognition and cell cytotoxicity using

human hepatoma cells (Hep G2), a suitable in vitro

model for the study of galactose interaction with

asialoglycoprotein receptors.

A k n o w l e d g e m e n t s

The authors aknowledge Fundação para a Ciência e

Tecnologia (Portugal) for financial support through

project PTDC/EQU-EPR/119631/2010.

R e f e r e n c e s [1] W. Lin, M. Chen, Carbohydr. Polym. 67 (2007)

474-480.

[2] M. Meier, M. Bider, V. Malashkevich, M. Spiess,

P. Burkhard, J. Mol. Biol. 300 (2000) 857-865.

[3] I.F. Uchegbu, A.G. Schätzlein, Polymers in drug

delivery, CRC, Boca Raton, Fla. ; London, 2006.

F i g u r e s

Figure 1. SEM image of the produced di-galactose-PLGA nanoparticles


Diego Repetto, Maria Caterina Giordano,

Christian Martella, Francesco Buatier de

Mongeot

Physics Department, University of Genoa, Italy

[email protected]

T r a n s p a r e n t a l u m i n u m

n a n o w i r e s e l e c t r o d e s

w i t h o p t i c a l a n d e l e c t r i c a l

a n i s o t r o p i c r e s p o n s e

f a b r i c a t e d b y d e f o c u s e d

i o n b e a m s p u t t e r i n g

Self-organized Ion Beam Sputtering (IBS) can lead to

the formation of ordered metallic nanowire (NW)

arrays by direct IBS patterning of a metal film

supported on a flat low cost glass substrate. For

increasing ion dose, the rippled metal film

decomposed into a disconnected NW array which

exhibits tunable anisotropic optical properties as

well as anisotropic electrical conductivity. So far, for

the metal sacrificial layer, noble metals as Au [1,2] or

Ag [3] were chosen since, beyond having a very low

resistivity, they support localized plasmon

resonances in the VIS-NIR spectral range [1,2].

In this work, we have explored the possibility to find

an alternative to transparent conductive oxides in

optoelectronic devices. In this view, self-organized Al

NWs electrodes have been obtained by defocused

IBS of polycrystalline Al films grown by sputter

deposition, adopting experimental conditions which

are compatible with industrial processes, in view of

the fabrication of low cost transparent electrodes.

The electrical characteristics have been acquired in

situ during the morphological evolution of the

samples, evidencing an increase of the electronic

transport anisotropy as a function of ion dose

between the two directions parallel and orthogonal

to the NWs axis.

Optical spectra in transmission also show a large

dichroism between the two directions, suggesting

the role of localized plasmons in the UV spectral

range. After a fluence of 1,2 x 1018

ions/cm2, the Al

NWs electrodes showed transparencies of about

40% and sheet resistances, longitudinal and

transverse, of 18 Ωsq and 4,5 Ωsq. At higher

fluences, higher transparencies are obtained at the

expense of conductivity.

R e f e r e n c e s [1] D. Chiappe, A. Toma, and F. Buatier de

Mongeot, Phys. Rev. B 86, 045414 (2012)

[2] D. Chiappe, A. Toma, and F. Buatier de

Mongeot, Small 9, 913-919 (2013)

[3] A. Toma et al., Journal of Applied Physics 104,

104313 (2008)


D. Ribeiro1, A. C. Alves

1, C. Nunes

1, S. Reis

1 1REQUIMTE, Departamento de Ciências Químicas,

Faculdade de Farmácia, Universidade do Porto,

Porto, Portugal

[email protected]

C h a r a c t e r i z a t i o n o f M o d e l

M e m b r a n e s u n d e r t h e

E f f e c t o f A n t i c a n c e r D r u g s

Cancer is a pathology that affects a large portion of

the world’s population [1]. It is an assembly of

diseases with various symptoms that significantly

decreases the patient’s life quality and has a high

rate of mortality [2]. One of the most commonly

used treatments for this pathology is chemotherapy,

involving the use of combinations of drugs to kill

cancer cells. Since these drugs either act directly on

the membrane or have to cross it to reach their

targets, the interactions between anticancer drugs

and biological membranes are of high importance.

The structure of biological membranes consists of a

phospholipid bilayer. In healthy cells,

phosphatidylcholine (PC) and phosphatidylserine

(PS) are some of the most common lipids, the PS

being found on the inner leaflet, but cancer cells’

membranes usually present higher heterogeneity in

constitution and the PS exposed to the extracellular

media [3]. The complexity of the membrane and all

the variables associated with the cells’ functions

makes it a very difficult model to study. As such,

artificial model membranes like liposomes might

present a viable alternative, being a simpler and

easier to manipulate model that accurately

simulates the cell membrane’s constitution and

behaviour.

That being said, the aim of our study was to assess

the effects of two anthracyclines used in

chemotherapy, daunorubicin and doxorubicin, on

the lipid membranes of four LUV formulation

models, two of them constituted by DMPC with and

without cholesterol, mimicking the normal cell

membrane, and the other two simulating the

tumoral cell membrane, constituted by a mixture of

DMPC:DOPC:DPPS (3:1:1) also with and without

cholesterol. Hepes buffer at pH 7.4 and Tris buffer at

pH 6.3 were used to mimic the normal and tumoral

tissue’s external pH, respectively. The effects of the

drugs on the different models were assessed by size

and zeta potential measurements, partition

coefficient (Kp) determination, drug location and

membrane fluidity studies. The four formulations

were then validated as model membranes for

healthy cells and cancer cells. This was achieved

through the study of similar properties in lines of

healthy and cancer cells under the influence of the

same drugs.

A c k n o w l e d g e m e n t s Catarina Alves and Cláudia Nunes thank FCT (Lisbon)

for the fellowships (SFRH/BD/82443/2011 and

SFRH/BPD/81963/2011), respectively. This work

received financial support from the European Union

(FEDER funds through COMPETE) and National

Funds (FCT, Fundação para a Ciência e Tecnologia)

through project Pest-C/EQB/LA0006/2013. The work

also received financial support from the European

Union (FEDER funds) under the framework of QREN

through Project NORTE-07-0124-FEDER-000067 .To

all financing sources the authors are greatly

indebted.

R e f e r e n c e s [1] Singh, S., Pharmacology for Dentistry 1st ed.

Apr, 2007: New age International.

[2] ACS. American Cancer Society - Information and

Resources for Cancer: Breast, Colon, Lung,

Prostate, Skin. 2014 [cited 2014; Available from:

http://www.cancer.org.

[3] Peetla, C., A. Stine, and V. Labhasetwar,

Biophysical interactions with model lipid

membranes: applications in drug discovery and

drug delivery. Mol Pharm, 2009. 6(5): p. 1264-76.


Ángel Ríos, Gema M. Durán, Ana M.

Contento

Department of Analytical Chemistry and Food

Technology, University of Castilla-La Mancha,

Ciudad Real, Spain

[email protected]

N e w a p p r o a c h e s i n t h e

d e v e l o p m e n t o f a n a l y t i c a l

m e t h o d o l o g i e s i n v o l v i n g

t h e u s e o f C d S e / Z n S

q u a n t u m d o t s

Quantum dots (QDs) are colloidal semiconductor

nanocrystals with a diameter typically in the range

from 1 to 10 nm and exceptional physic-chemical

properties. Their use, for different purposes has

increased in the last years, especially in the

development of new methods of analysis. Thus,

their use for the development of optical sensors is

one of the most developing fields of nanotechnology

so far. Several works have demonstrated their

optoelectronic properties based on changes on the

QDs photoluminescence, significantly influenced by

changes on the QDs surface charge or ligands that

affect electron-hole recombination. However, most

of analytical applications involve the use of

biocompatible QDs with aqueous media. In this way,

the colloidal synthesis route of QDs [1] is the most

used due to the formation of high quality QDs

nanocrystal and their long storage time. Therefore,

the development of methodologies to allow the

aqueous compatibly of QDs is necessary.

For this purpose, the aim of this communication is to

show several alternatives involving the modification

of the QDs surface and the affinity by the aqueous

media, without significantly modifications in their

initial properties and the subsequently analytical

applications (Figure 1).

On the one hand, a simple and fast procedure for

water solubilization of CdSe/ZnS QDs using

microwave irradiation was optimized [2]. For this

purpose, the replacement of initial hydrophobic

ligands (TOPO/TOP) with different hydrophilic

heterobifunctional thiol ligands, as L-cysteine, 3-

mercaptopropionic acid and cysteamine were

carried out in a simple and fast way (only 40 s).

Thus, the solubilization and the surface

modification of QDs were achieved for

subsequently analytical applications. For instance,

the particular reactions with different

sulphonylurea herbicides were exploited.

On the other hand, the use of water soluble

CdSe/ZnS QDs for sensitive detection and

quantification of paraquat in water samples was

carried out [3]. It was found that 3-MPA modified

CdSe/ZnS is sensible to the presence of paraquat.

The proposed analytical method thus satisfies the

need for a simple, sensible and rapid methodology

to determine residues of paraquat in water samples,

as required by the increasingly strict regulations for

health protection introduced in recent years. The

sensitivity of the method, expressed as detection

limits, was as low as 3.0 ng L-1

. The lineal range was

between 10- 5x103 ng L-1

. RSD values in the range of

71-102% were obtained. The analytical applicability

of proposed method was demonstrated by analyzing

water samples from different origins.

In addition, an optical sensor for vanillin in food

samples using CdSe/ZnS quantum dots (QDs)

modified with β-cyclodextrin (β-CD) was developed

[4]. This vanillin-sensor is based on the selective

host-guest interaction between vanillin and β

cyclodextrin. The procedure for the synthesis of β

cyclodextrin- CdSe/ZnS (β-CD-CdSe/ZnS-QDs)

complex was optimized, and its fluorescent

characteristics are reported. It was found that the

interaction between vanillin and β-CD-CdSe/ZnS QDs

complex produced the quenching of the original

fluorescence of β-CD-CdSe/ZnS-QDs according to

the Stern-Volmer equation. The analytical potential

of this sensoring system was demonstrated by the

determination of vanillin in synthetic and food

samples. The method was selective for vanillin, with

a limit of detection of 0.99 μg mL-1

, and a

reproducibility of 4.1% in terms of relative standard

deviation (1.2% under repeatability conditions).

Recovery values were in the 90-105% range for food

samples. Recent promising results can been

obtained by the electrophoretic separation involving

the use of β-CDCdSe/ ZnS-QDs with different vanillin

related compounds and their tandem detection by

DAD-FD-ELSD. Other alternative has been the


development of a continuous flow method involving

the CdSe/ZnS QDs. The main innovation in this work

is the high throughput, the level of automation, the

low consumption of reagents, and the low wastes

generation. This application takes the exceptional

optical properties of β- CD-CdSe/ZnS QDs for the

determination of ascorbic acid in different fruit

juices and pharmaceutical preparations.

Finally, the need to develop new methodologies that

allow screening for compounds of interest in various

areas without the need to use sophisticated

instrumentation and an exhaustive determination

using inexpensive portable device open new

approach for screening methods. For this purpose,

the fabrication of simple and economical colloidal

CdSe/ZnS quantum dots (QDs)-modified paper

device, constituttes and exceellent trend. This new

appproach for screening methods demonstrates

that QDs canbe used as probes for developing a

new generation of paper-based analytical

applications.

A c k n o w l e d g e m e n t s Financial support from the Spanish Ministry of

Economy and Competitiveness (CTQ2013-48411-P)

is gratefully acknowledged

R e f e r e n c e s [1] Z.A. Peng, X. J. Peng, J. Am. Chem. Soc., 123

(2001) 183

[2] G. M. Duran, M. R. Plata, M. Zougagh, A M.

Contento, and A. I. Rios. J. Colloid Interface Sci.

428 (2014) 235

[3] G. M. Duran, A. M. Contento, and A. Rios, Anal.

Chim. Acta. 801 (2013) 84

[4] G. M. Duran, A. M. Contento, and A. Rios,

Talanta, 131 (2015) 286

F i g u r e s

Figure 1. Approaches for the modification and analytical applications of quantum dots.


C.M.M. Rosário1, O.N. Gorshkov

2, A.

Kasatkin2, I. Antonov

2, D. Korolev

2, A.N.

Mikhaylov2, N.A. Sobolev

1,3

1Departamento de Física and I3N, Universidade de

Aveiro, Portugal 2Lobachevsky State University of Nizhni Novgorod, 0

Russia 3National University of Science and Technology “MISiS”,

Moscow, Russia

[email protected]

R e s i s t i v e s w i t c h i n g a n d

i m p e d a n c e s p e c t r o s c o p y i n

m e t a l - o x i d e - m e t a l t r i l a y e r s

w i t h S i O x a n d Z r O 2 : a

c o m p a r a t i v e s t u d y

The ReRAM, acronym of resistive (switching)

random access memories, are candidates to lead the

new generation of non-volatile memories and are

based on a phenomenon known as resistive

switching (RS) [1]. The research on this

phenomenon, known since the 1960’s [2], was

boosted by the link to the memristor, a passive

fundamental circuit element proposed by Leon Chua

in 1971 [3], demonstrated by a group of the HP Labs

in 2008 [4]. Although the titanium dioxide is

considered a prototypical memristive material [5],

research on RS in structures containing materials

that are compatible with the CMOS technology,

nowadays the leading technology in the fabrication

of integrated circuits, such as silicon oxide or

zirconium oxide, may favour the future market

introduction of RS-based devices.

In this work, Au/oxide/TiN structures, obtained by

RF-magnetron sputtering deposition of 40 nm thin

films of silicon and zirconium oxides, were

investigated by means of current-voltage (I-V)

characteristics and impedance spectroscopy and

compared based on the results obtained.

In the SiOx structure, the I-V characteristics exhibit

bipolar-like RS, with a ratio between the

resistances of the high resistance state (HRS) and

the low resistance state (LRS) bigger than 102, at 1

V read voltage. The observed RS is sensitive to the

Au electrode exposure to the atmosphere, which

enhances the RS (see Fig. 1). A decrease in the

voltage application time leads to an increase in the

voltage required to induce the transition from HRS

to LRS. The two different states show a very

distinct behaviour as the temperature is varied:

whereas the LRS's resistance has a very weak

temperature dependence and decreases with

decreasing temperature, in the HRS the resistance

increases as the temperature drops. The latter

state's resistance temperature dependence is

described by a thermal activation of charge

carriers, with activation energies of 0.46 and 4.3

meV in the 6 to 130 K temperature region. The

weak dependence of the resistance with the Au

electrode area and the invariance of the

structure's capacitance between the states suggest

a filamentary mechanism for the observed RS. Due

to the oxygen's influence on the RS, the creation

and disruption of the filaments should involve

redox reactions.

The ZrO2 structures also exhibit bipolar-like RS,

with a ratio of ca. 102 between the resistance of

the HRS and of the LRS, read at 1 V. However, the

atmospheric exposure decreases the above

mentioned ratio, having the opposite effect on the

RS, relatively to the SiOx case (see Fig. 2). The

increase in this ratio via pulsed measurements

evidences the existence of at least two competing

processes in the RS. The impedance spectra show a

similar behaviour between these structures and

the SiOx ones, even though there is a bigger

dependence on the electrode area, behaviour that

deviates from a single filament model. The

addition of a germanium oxide (GeOx) layer

between the Au electrode and the ZrO2 film

enhances the repeatability of the I-V

characteristics.


R e f e r e n c e s

[1] D. S. Jeong, R. Thomas, R. S. Katiyar, J. F. Scott,

H. Kohlstedt, A. Petraru, C. S. Hwang, Rep. Prog.

Phys., 75 (2012): 076502.

[2] T. W. Hickmott, J. Appl. Phys., 33 (1962): 2669–

2682.

[3] L. Chua, IEEE Trans. circuit theory, CT-18 (1971):

507 – 519.

[4] D. B. Strukov, G. S. Snider, D. R. Stewart, R. S.

Williams, Nature, 453 (2008): 80–83.

[5] K. Szot, M. Rogala, W. Speier, Z. Klusek, A.

Besmehn, R. Waser, Nanotechnology, 22

(2011): 254001.

F i g u r e s

Figure 1: Typical I-V characteristics obtained for the Au/SiOx/TiN

structures with a voltage sweep rate of ca. 1 V/s. The data displayed

with the empty symbols was measured with a 300 nm-SiO2 mask

covering the Au electrode, evidencing the importance of the

atmospheric exposure for the RS process in increasing the resistance

ratio between the high resistance state (HRS) and the low resistance

state (LRS). The red dashed arrow indicates the initial direction of

measurement.

Figure 2: Typical I-V characteristics obtained for the Au/ZrO2/TiN

structures with a voltage sweep rate of ca. 1 V/s (for the data shown

with the circular symbols). The data displayed with the empty symbols

was measured with a 300 nm-SiO2 mask covering the Au electrode,

evidencing the impact of the atmospheric exposure for the RS process,

in this case decreasing the resistance ratio between the high resistance

state (HRS) and the low resistance state (LRS). The data displayed with

the triangular symbols were measured in a pulsed regime (with a

voltage sweep with 500 μs pulses for each voltage level, intercalated

with a time interval where there was no applied voltage), which

enabled a higher resistance ratio even without the mask. The red

dashed arrow indicates the initial direction of measurement.


Choon-Ming Seah1,2

, Brigitte Vigolo1,

Siang-Piao Chai3, Abdul Rahman

Mohamed2

1Institut Jean Lamour, CNRS-Université de Lorraine,

Vandoeuvre-lès-Nancy, France 2School of Chemical Engineering, Engineering Campus,

Universiti Sains Malaysia, Nibong Tebal, Seberang Perai

Selatan, P. Pinang, Malaysia 3Chemical Engineering Discipline, School of

Engineering, Monash University, Jalan Lagoon Selatan,

Selangor, Malaysia

[email protected]

A n I m p r o v e d W e t C h e m i c a l

A p p r o a c h F o r T h e S e p a r a t i o n O f

G r a p h e n e F r o m N i c k e l F o i l T o

T h e R e u t i l i z a t i o n O f C a t a l y s t

Chemical Vapor Deposition (CVD) is the most widely

studied approach for the synthesis of wafer scale

graphene. To fully utilize the magnificent properties

of the graphene, the separation of graphene from

the metal catalyst is important. To date, majority of

the studies utilizing the wet chemical etching

method that scarifying the metal catalyst in order to

obtain free standing graphene. In order to realize

the re-use of catalyst for minimization of the waste,

an improved simple wet chemical etching method

approach is proposed. Nickel has relatively high

carbon solubility under elevated temperature as

compared with other catalyst. Part of the carbon

dissolved in the bulk nickel was not been used for

the formation of graphene and later reacted with

nickel to form nickel carbide crystal. After CVD, the

nickel foil with graphene was floated onto iron

nitrate solution with concentration of 1 mol/dm3, an

etching agent. The etching agent would intercalate

between graphene and nickel to etch the surface of

nickel for separation under slower rate. The

inertness of nickel carbide would act as the

protective layer to slowdown the chemical attack

onto the bulk nickel foil and preserve it. The

remaining nickel foil after the separation was used

for same CVD and separation process to obtain

another layer of graphene. A nickel foil with a

thickness of 125μm can be reused to synthesis up to

6 pieces of graphene without large deviation in

properties.


Bea Salesa, Ana V. Sánchez-Sánchez, José

Luis Mullor, Juan Manuel Serrano

Sesderma Laboratories, Polígono Industrial

RafelbuñolC/Massamagrell 3, RafelbuñolBionos

Biotech, Biopolo La Fe, Valencia, Spain

[email protected]

R e p a i r O f U V L i g h t - I n d u c e d

D n a D a m a g e

Human skin exposure to ultraviolet (UV) radiation

promotes DNA damage, which gives rise to aging,

mutations, cell death and the onset of carcinogenic

events. UV radiation introduces different types of

damage into the DNA, being predominant the

formation of cyclobutanepyrimidine dimers (CPDs)

by covalent linkage between two adjacent

pyrimidine nucleotides. Generation of CPDs is critical

for photocarcinogenic processes, because they

distort the DNA helix and are linked to mutations in

tumour-suppressor genes expressed in skin cancer,

such as gene p53.

Fish Medaka (Oryzias latipes) is a vertebrate model

organism used in research. It is easy to handle and

ideal for the screening of new functional compounds

due to their large number of progeny per

generation. Moreover, it offers the advantage of

performing the functional assays “in vitro” when

used in the eleutheroembryo phase. We must

remark that all the experiments were carried out in

vitro using eleutheroembryos.

In this study we evaluated whether DNA repair, in

UV-irradiated Medaka eleutheroembryos, could be

enhanced through topical application of a

preparation containing DNA repair enzymes, amino

acids, teprenone and Zn+ (EZ). In order to enhance

nuclear delivery, each ingredient was encapsulated

individually into liposomes.

Liposomes are small vesicles composed of one or

more lipid bilayers, which improve bioavailability of

active ingredients and provide a sustained release.

Their structure is very similar to biological

membranes and thus, are biodegradable and non

toxic. Moreover, they show higher efficiencies at

lower concentrations and prevent oxidation and

degradation of the ingredients.

All the liposomes used, were manufactured by

Sesderma and had the following characteristics: Size

between 50 and 150 nm, Polidispersity Index below

0.2, and Z potential between [30] and [150] mV

(Delsa Nano C, Particle Analyzer).

Results

We assayed endogenous DNA repairing mechanism

in cells from Medaka fish embryos by measuring the

reduction of CPDs, after UV irradiation (fig.1A).

Subsequently, by comparing the amount of CPDs

formed immediately after UV light irradiation on

cells treated with a control formulation (EZ minus

active ingredients) and cells treated with EZ, we

observed a significant decrease (36%) in the

formation of CPDs (fig. 1B).

p53 helps preventing genome mutation, due to its

crucial role in regulating cellular responses to

various DNA-damaging agents, including UV

radiation. p21 is directly linked to p53 because its

expression is tightly controlled by the protein p53.

We also studied the effect of UV light in the

expression levels of p53 and p21 by comparing

samples with or without irradiation. We found that

the expression levels of p53 and p21 did not change

in embryos not irradiated or embryos irradiated

with UV light at t=0 minutes or t=15 minutes (fig 2A,

C) indicating that at 15 min a p53- mediated

response is not yet active. On the other hand, we

observed that EZ treatment reduced the

endogenous level of p53, allowing for an early

damage response to UV light (t=15 min after UV

irradiation) increasing the levels of p53. This early

response induced by EZ treatment provoked in turn

an increase in p21 expression of 130% as early as 15

min after irradiation (fig 2B, D).

c-Fos is required for excision repair processes

triggered by DNA lesions produced by UV radiation.

Therefore, we measured c-Fos expression level in

control embryos and embryos treated with EZ,

exposed or not to UV light. Results show that c-Fos

does not significantly increase 15 minutes after UV

radiation in control embryos (fig. 3A). On the the

contrary, 15 minutes after UV radiation c-Fos is


overexpressed in embryos previously treated with

EZ (fig. 3B). In addition, we measured cell cycle

immediately after irradiation with UV light and 15

minutes post irradiation, and we found that there

were no significant changes in cell distribution in

each cell cycle phase (fig. 4A, C, E). Furthermore, we

measured cell cycle immediately after UV light

irradiation on cells treated with the control

preparation and embryos treated with EZ, and we

did not observe any significant changes in cell

distribution (fig. 4B, D, F) further indicating that the

above gene expression changes detected, were not

a consequence of changes in the cell cycle.

Conclusions

Results indicate that EZ protects cells against UV

light-induced damage through reducing the amount

of CPDs in the DNA and triggers the endogenous

DNA repair mechanisms that involve the action of

p53, p21 and c-Fos.

R e f e r e n c e s

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cancer. 2004. Cutis.74(5 Suppl):10-13.

[2] Karakoula A, Evans MD, Podmore ID, Hutchinson PE,

Lunec J, Cooke MS. Quantification of UVR-induced DNA

damage: global- versus gene-specific levels of CPDs. J

Immunol Methods. 2003 Jun 1; 277(1-2):27-37.

[3] Elmets, C. A. & Mukhtar, H. (1996) Prog. Dermatol. 30, 1–16.

[4] Brash DE, Rudolph JA, Simon JA, Lin A, McKenna GJ,

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JA, Halperin AJ, Baden HP, Shapiro PE, Bale AE, Brash DE

(1993) Proc Natl Acad Sci USA 90:4216 – 4220. 4.

[6] Dumaz N, Drougard C, Sarasin A, Daya-Grosjean L

(1993) Proc Natl Acad Sci USA90:10529 –10533.

[7] Tron VA, Li G, Ho V, Trotter MJ. Ultraviolet radiation-

induced p53 responses in the epidermis are

differentiation-dependent. J Cutan Med Surg. 1999

Jul;3(5):280-3.

[8] Halicka HD, Huang X, Traganos F, King MA, Dai W,

Darzynkiewicz Z. Histone H2AX phosphorylation after

cell irradiation with UV-B: relationship to cell cycle

phase and induction of apoptosis. Cell Cycle. 2005

Feb;4(2):339-45.

[9] Zhao H, Traganos F, Darzynkiewicz Z. Kinetics of the

UV-induced DNA damage response in relation to cell

cycle phase. Correlation with DNA replication.

Cytometry A. 2010 Mar;77(3):285-93.

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Craig RW. Participation of p53 protein in the cellular

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[11] Smith ML, Ford JM, Hollander MC, Bortnick RA,

Amundson SA, Seo YR, Deng CX, Hanawalt PC, Fornace

AJ Jr. p53-mediated DNA repair responses to UV

radiation: studies of mouse cells lacking p53, p21,

and/or gadd45 genes. Mol CellBiol. 2000

May;20(10):3705-14.

[12] Christmann M, Tomicic MT, Origer J, Aasland D, Kaina B.

c-Fos is required for excision repair of UV-light induced

DNA lesions by triggering the re-synthesis of XPF. Nucleic

Acids Res. 2006;34(22):6530-9. Epub 2006 Nov 27.

[13] Gasparro, F. P., Mitchnick, M. & Nash, J. F. (1998)

Photochem. Photobiol. 68, 243–256.

[14] Emanuele E, Altabas V, Altabas K, Berardesca E. Topical

Application of Preparations Containing DNA Repair

Enzymes Prevents Ultraviolet-Induced Telomere

Shortening and c-FOS Proto-Oncogene

Hyperexpression in Human Skin: An Experimental Pilot

Study. J Drugs Dermatol. 2013 Sep 1;12(9):1017-21.

[15] Berardesca E, Bertona M, Altabas K, Altabas V,

Emanuele E. Reduced ultraviolet-induced DNA damage

and apoptosis in human skin with topical application of

a photolyase-containing DNA repair enzyme cream:

clues to skin cancer prevention.Mol Med Rep. 2012

Feb;5(2):570-4.

[16] Wittbrodt J, Shima A, Schartl M (2002) Medaka - a model

organism from the far East. Nat Rev Genet3:53-64.

[17] Reinhardt HC, Schumacher B. The p53 network: cellular

and systemic DNA damage responses in aging and

cancer.Trends Genet. 2012 Mar;28(3):128-36.

[18] Mirzayans R, Andrais B, Scott A, Murray D. New

insights into p53 signaling and cancer cell response to

DNA damage: implications for cancer therapy. J

Biomed Biotechnol. 2012;2012:170325.

[19] Cazzalini O, Scovassi AI, Savio M, Stivala LA, Prosperi E.

Multiple roles of the cell cycle inhibitor p21(CDKN1A)

in the DNA damage response. Mutat Res. 2010 Apr-

Jun;704(1-3):12-20.

[20] Leeman MF, Curran S, Murray GI. The structure,

regulation, and function of human matrix

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[21] Kuivanen TT, Jeskanen L, Kyllönen L, Impola U,

Saarialho-Kere UK Transformation-specific matrix

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2006 Sep;19(9):1203-12

F i g u r e s


Mário G. Silveirinha

Instituto de Telecomunicações-University of Coimbra,

Coimbra, Portugal

[email protected]

T a m i n g l i g h t a t t h e n a n o s c a l e

w i t h m e t a m a t e r i a l s

Structured materials with unusual electromagnetic

properties have received much attention after some

influential works demonstrated that by introducing

a new length scale in conventional metals and

dielectrics–by tailoring the microstructure– it is

possible to radically modify the electromagnetic

response.

In this talk, I will present an overview of our research

work on electromagnetic metamaterials and

plasmonics, and discuss the unusual potentials of

media with near zero permittivity, materials with a

chiral response, and materials with anomalous

dispersion. In particular, I will explain how low loss

plasmonic materials may offer the opportunity to

have light localization in open bounded systems with

infinitely long oscillation lifetimes and no radiation

loss [1] [2] . Moreover, I will show how chiral light

may be used to harness the sign of optical forces,

forcing a material body to be pulled towards a

direction opposite to the photon flow (optical

tractor beam). Finally, time permitting, I will discuss

how by controlling the topology of a metamaterial it

is possible to engineer the material dispersion and

create reverse rainbows [3]-[5]. It is envisioned that

these materialsmay useful for the design of

improved optical instruments insensitive to

chromatic aberrations.

R e f e r e n c e s

[1] M. G. Silveirinha, “Trapping Light in Open

Plasmonic Nanostructures”, Phys. Rev. A,

89,023813, 2014.

[2] M. G. Silveirinha, “Optical instabilities and

spontaneous light emission by polarizable

movingmatter”, Phys. Rev. X, 4, 031013, 2014.

[3] T. A. Morgado, J. S. Marcos, J. T. Costa, J. R.

Costa, C. A. Fernandes, M. G.

Silveirinha,“Reversed Rainbow with a Nonlocal

Metamaterial”, Appl. Phys. Lett.,105, 264101

(2014).

[4] J. T. Costa, M. G. Silveirinha, “Achromatic Lens

Based on a Nanowire Material with Anomalous

Dispersion”, Optics Express, 20, 13915, 2012.

[5] M. G. Silveirinha, “Anomalous dispersion of light

colors by a metamaterial prism”, Phys. Rev.

Lett., 102, 193903, 2009


A. Soto Beobide1, E. D. Vogl

1, S.M.

Iconomopoulou1, Deniz Korkmaz

2, Özlem

Türkarslan2,G.A. Voyiatzis

1

1Foundation for Research & Technology-Hellas–

Institute of Chemical Engineering Sciences (FORTH /

ICE-HT) Rio-Patras, Greece 2Kordsa Global R&D Center, Kocaeli, Turkey

[email protected]

C a r b o n N a n o t u b e r e i n f o r c e d

T e x t i l e s f o r C i v i l P r o t e c t i o n

S e r v i c e s

A research joint venture led by Foundation for

Research & Technology-Hellas, partnered with

KORDSA Global, is developing new processes and

technologies to scale up the production of carbon

nanotubes dispersed in polymers, to create textile

fibers with enhanced performance and new

functionality that cannot be provided by polymers or

traditional composites.

Protective textiles are a field of intense research

activity. Body armour materials have traditionally

been designed to protect the wearer against any

kind of weapon threats. Several new fibers and

construction methods for bullet-proof fabrics have

been developed besides woven Kevlar®, such as

DSM’s Dyneema®, Honeywell’s Gold Flex® and

Spectra®, Teijin Twaron’sTwaron® and Toyobo’s

Zylon®. These high performance fibers are

characterized by low density, high strength and high

energy absorption. However, to meet the protection

requirements for typical ballistic threats, several

layers of fabric are required. It is also frequently to

improve the body armour with stab resistant

materials. The resulting bulk and stiffness of the

armour limits the wearer’s mobility and agility. As a

consequence, civil protection services are not used

to wear the protection vest all the time, performing

usual tasks such as patrolling or driving, since the

models currently on the market are heavy, bulky &

inflexible. There is an obvious need to develop

flexible and lightweight protective body armour.

This gap can be filled by means of carbon based

materials. Since Iijima’s report on carbon nanotubes

(CNT) in 1991[1], scientists have been attracted by

CNT’s unique atomic structure and properties.

Because of the combination of low density,

nanometer scale diameters, high aspect ratio, and

more importantly, unique physical properties such

as extremely high mechanical strength and modulus,

CNTs are ideal as potential reinforcing filler without

adding extra weight and contributing with excellent

performance. The inclusion of CNTs in a polymeric

matrix holds the potential to improve the host

material’s mechanical properties by orders of

magnitude well above the performance of

traditional fillers. The challenges for developing high

performance polymer/CNTs composites include the

dispersion of CNTs in the polymeric matrix and

interfacial interactions to ensure efficient load

transfer from the polymeric matrix to the CNTs. The

challenge of achieving efficient CNT dispersion and

orientation within the polymer composite poses a

substantial obstacle to the development of relevant

beyond the state of the art fabrics. In other words,

the mechanical properties of CNT composites fibers

are highly dependent on CNT loading, dispersion

and orientation, as well as pertinent to the polymer

matrix characteristic properties. Substantial research

efforts have been undertaken toward preparation

(in the lab-scale) and characterization of polymer

nanocomposites.

Experimental methods: The MWCNTs (NTX1) used

in this work were purchased from NanoThinx S.A.

(Greece). Carboxyl (-COOH) functionalized MWCNTs

(NTX5) were also purchased by NanoThinx. Chemical

oxidation was carried out by two pertinent

treatments, one mild by utilizing nitric acid followed

by hydrogen peroxide and a second one, a mixture

of nitric/sulfuric acid, significantly more aggressive.

The polymer used in this work is poly(ethylene

terephthalate), PET (iv ≥ 1 dL/g). Nanocomposites of

0.5, 1 and 2 wt% were prepared by melt mixing

under nitrogen atmosphere in a homemade batch

mixer. Polymer films were prepared by melt

pressing a small part of the master batch at 285°C

followed by quenching in ice water.

TGA in N2 atmosphere was conducted for all

MWCNTs shown. In the thermograms shown in

Figure 2, the most thermally stable material is the


as-received MWCNTs (NTX1), which does not lose

weight after being heated to 600°C. This is due to

the low content of amorphous carbon in the as

received material. When a mild oxidation is

conducted, the amount and rate of weight loss is

very similar to that of the asreceived material,

indicating that no or very few amorphous carbon

has been generated because of the acid treatment.

The aggressive oxidation treatment, on the other

hand, significantly degrades the graphitic structure

of the MWCNTs by converting it to amorphous

carbon, which is evident by the pronounced weight

loss observed early in TGA curve.

The tensile stress-strain curves of pure PET and the

examined PET/MWCNTs composites at 0.5, 1, 2 wt%

loading are presented in Figure 3. The absence of

significant improvements in the mechanical

properties of the NTX5 composites may be the result

of aggregation, as well as poor interfacial interaction

between the NTX5 MWCNTs and PET. Quite

different properties are obtained for the composites

that CNTs were oxidized by mild and aggressive

treatment. With respect to neat PET, these

composites showed an increase in the strength and

failure strain, although the improvement in elastic

modulus may not be statistically significant. The

large improvement in the tensile properties of these

composites is attributed to the improved dispersion

of MWCNTs inside the matrix and improved

interactions between the MWCNTs and PET, mostly

by hydrogen bonding, enhancing the interfacial

bonding.

Fabrication of PET/CNTs for textile applications both

on laboratory and industrial scale needs to be

optimized in terms of processing conditions that

include pre-mixing parameters, feeding rate,

temperature of extrusion die and screw speed in

order to get new carbon nanotubes based materials

with enhanced properties. Carbon nanotubes-PET

monofilaments prepared at industrial scale (based

on laboratory scale efforts) will be characterized and

optimized for the required textile application.


The research leading to these results was cofounded

by the European Regional Development Fund

(FP7/2007-2013) and Western Greece Region

national resources under the grant agreement n°

235527 (LEADERA - Code: 2013-006 INPROTEX).

R e f e r e n c e s

[1] Iijima S., Nature, 354 (1991) 56-58.

F i g u r e s

Figure 1: Scheme of CNT functionalization

Figure 2: TGA curves of MWCNTs samples

Figure 3: Representative stress-strain curves for PET and PET

nanocomposites of all concentrations.


M. Tarequzzaman, J. D. Costa, J. Borme,

M. Gonzalez-Debs, B. Lacoste, E. Paz, S.

Serrano-Guisan, R. Ferreira and P. Freitas

INL-International Iberian Nanotechnology Laboratory,

Braga, Portugal

[email protected]

L a r g e p o w e r e m i s s i o n i n M T J

b a s e d s p i n t o r q u e

n a n o - o s c i l l a t o r s u s i n g a f r e e

l a y e r n e a r t h e i n - p l a n e t o

o u t - o f p l a n e t r a n s i t i o n

Spin torque nano-oscillator (STNO) explore dynamic

magnetic effects induced in the free layer of

magnetoresistive devices induced by spin polarized

currents. Soon after its discovery, STNO draw much

attention to the researchers because of its

advantages over conventional CMOS oscillators. The

advantage of STNO covers, simple structure, smaller

footprint (<200nm), high frequency tunability, large

frequency (2-20 GHz range oscillations depending on

magnetic field), low cost and good compatibility

with the standard complementary metal oxide

semiconductor (CMOS) technology [1-3]. However

several challenges need to be addressed before

STNOs are to be used in practical purpose. As it has

critical disadvantages in terms of lower output

power and relatively large linewidth in comparison

with voltage controlled oscillators (VCOs) [4].

The power generation of STNO depends on several

factors; resistance change induced by the

magnetoresistance (MR) effect in the magnetization

oscillations is one of them. Therefore, MgO based

magnetic tunnel junctions (MTJs) with higher MR

ratio (>50%) deliver larger microwave signals than

metallic oscillators with lower MR ratio (<10%) [3].

In addition to this, another requirement for a large

power emission is the excitation of large-amplitude

oscillations. To this end, several configurations for

the magnetization of the free and pinned layer have

been proposed.

In this work, MTJ stacks (50 Ta/ X CoFe40B20/MgO

[3.0 Ohm-µm2]/2.2 CoFe40B20/0.85 Ru/2.0 CoFe30/20

IrMn (Thickness in nanometer) with an MgO barriers

have been deposited using a Singulus TIMARIS PVD

system. The free layer thickness (X) was changed

between 2.0nm (free layer magnetization in plane)

down to 1.0nm (free layer magnetization

perpendicular to plane). These stacks were then

patterned into nanopillars with different shapes

(circular and elliptical) and dimension (50 nm to 200

nm in diameter) by electron beam lithography and

ion milling technique.

The nano-pillars have been measured in a radio

frequency transport measurement setup at room

temperature. It is found that a large power output

with a small linewidth is obtained in nano-pillars

with a free layer thickness of 1.4nm which still have

an in-plane magnetization but right at the transition

to out-of-plane magnetization, i.e., the in-plane free

layer experiences a very strong perpendicular

anisotropy contribution.

An example of such measurements is shown in Fig.

1.a. for a pillar with circular shape and 150nm

diameter. The result, show in Fig. 2, displays

microwave signals with maximum power of 300 nW

and narrow linewidth as small as 30 MHz. These

STNOs operate with frequencies in the range

between 2.4-2.8GHz .The large power output and

narrow linewidth of these nano-oscillators make

them good candidates for integration with CMOS

circuits such as new generation Phase-Locked-Loops

(PLLs).

R e f e r e n c e s

[1] Z. Zeng, G. Finocchio, B. Zhang, P. K. Amiri, J. A.

Katine, I. N: Krivorotov, Y. Huai, J. Langer, B.

Azzerboni, K. L. Wang, and H. Jiang, Sci. Rep. 3,

(2013) 1426

[2] S. I. Kiselev, J. C. Sankey, I. N. Krivorotov, N. C.

Emley, R. J. Schoelkopf, R. A. Burman, D. C.

Ralph, Nature. 425, (2003), 380–383.

[3] Z. Zeng, P. K. Amiri, I. N. Krivorotov, H. Zhao, G.

Finocchio, J.-P. Wang, J. A. Katine, Y. Huai, J.

Langer, O. K Galatsis, K. L. Wang, and H. Jiang,

ACS Nano 6, (2012) 6115–6121

[4] H. S. Choi, S. Y. Kang, S. J. Cho, I. Y. Oh, M. Shin,

H. Park, C. Jang, B. C. Min, S.Kim, S.Y. Park, C. S.

Park, Sci. Rep. 4,(2014) 5486


F i g u r e s

Figure1: a) Illustration of radio frequency (RF) measurement setup. b) The measured MTJ stack and nanopillar dimension.

Figure2: a) Transport measurement (two contact measurement) in easy and hard axis. The arrow indicating the RF measurement point b)

Microwave emission spectra measured in positive bias currents (Black spectrum) and negative bias currents (Red Spectrum). c) Shows the results, in

terms of power emissions, linewidth, frequency tunability and resistance.


Ana Vila1, Clotilde Costa

2, Carlos

Rodríguez-Abreu1, Miguel Abal

2, Rafael

López-López2, José Rivas

3

1International Iberian Nanotechnology Laboratory

(INL), Braga, Portugal 2 Translational Medical Oncology Group, Complejo

Hospitalario Universitario de Santiago de Compostela,

Santiago de Compostela, Spain 3Department of Applied Physics; Nanotechnology and

Magnetism Lab — NANOMAG, University of Santiago

de Compostela, Santiago de Compostela, Spain

[email protected]

D e s i g n e d N a n o c o m p o s i t e

M a g n e t i c B e a d s f o r i s o l a t i o n o f

C i r c u l a t i n g T u m o r C e l l s ( C T C )

In recent years, there has been an increasing

interest in the isolation of Circulating Tumor Cells

(CTC), which are metastasis cells circulating in

peripheral blood of cancer patients, for prognostic,

diagnostic and therapeutic applications. Magnetic

separation is one of the methods of choice for cell

isolation. For this purpose, submicrometer

polymeric beads loaded with different content of

magnetite nanoparticles (30-44 wt%) were

prepared by mini-emulsion polymerization and

characterized in terms of size, and magnetic

properties. The beads were functionalized with a

customized method with Protein A for

incorporating antibodies and studying their

interaction with EpCAM cancer cells.

Superparamagnetic and colloidally stable

polymeric beads with size between 140 and 200

nm were obtained. Moreover, they were

covalently covered by protein A and therefore

enabled to be coupled with antibodies. After

incubation of the polymeric beads with EpCAM

cells, it was confirmed by flow cytometry that the

beads were specifically and efficiently adsorbed on

the cell´s surface and without aggregation of free

beads. It was found that the magnetic isolation of

labelled cells, became more efficient as the

magnetite content increased up to 44 wt%.

Notably, the synthesized nanocomposite polymer

beads were more efficient for cell isolation than

micron-sized commercial beads, which much

improves sample stability for handling and enables

a larger specific contact area.

F i g u r e s

Figure 1: Bead Structure

Figure 2: SEM image of beads

Table 1: Bead Characteristics

Table 2: Cell Isolation Efficiency of beads


M.Vila1, M.C.Matesanz

2, G.Gonçalves

1,

M.J.Feito2, J.Linares

2, P.A.A.P.

Marques1,M.T.Portolés

2, M.Vallet-Regi

3,4

1TEMA-NRD, Mechanical Engineering Department and

Aveiro Institute of Nanotechnology (AIN),University of

Aveiro, Aveiro, Portugal 2

Department of Biochemistry and Molecular Biology I,

Faculty of Chemistry, UCM, Madrid, Spain 3Department of Inorganic and Bioinorganic Chemistry,

Faculty of Pharmacy, UCM, Madrid, Spain 4Networking Research Center on Bioengineering,

Biomaterials and Nanomedicine, CIBER-BBN, Spain

[email protected]

N a n o g r a p h e n e O x i d e

m e d i a t e d c e l l h y p e r t h e r m i a

Graphene and more specifically, pegylated

grapheme oxide (GO) has been proposed as a highly

efficient in vivo photothermal therapy agent due to

its strong Near- Infrared (NIR 700-1100 nm range)

optical absorption ability. Its small two dimensional

size could be unique performing when compared to

any other nanoparticle, therefore, light should be

given to the hyperthermia route and the kind of GO

cell interactions induced in the process. The type of

cell damage and toxicity produced by Near-infrared

(NIR) laser irradiation has been evaluated as a

function of exposure time and laser power in order

to control the temperature rise and consequent

damage in the GOs containing tumoral cell culture

medium. The results showed that cell culture

temperature (after irradiating cells with internali zed

GO) increases preferentially with laser power rather

than with exposure time. Moreover, when laser

power is increased, necrosis is the preferential cell

death leading to an increase of cytokine release to

the medium. The results suggested that tailoring cell

death, the threshold for producing thermal ablation

with soft or harmful damage could be specifically

controlled and so, the immune response.


X. G. Wang, Y. ko‘lenko, Lifeng Liu International Iberian Nanotechnology Laboratory (INL),

Braga, Portugal

[email protected]

D i r e c t G r o w t h o f N i c k e l

P h o s p h o r i d e N a n o n e e d l e s o n

N i c k e l F o a m f o r E f f i c i e n t

E l e c t r o c a t a l y t i c H y d r o g e n

E v o l u t i o n

Hydrogen is a future energy carrier for both

stationary and motive power generation. Water

splitting offers a clean and sustainable way to

produce hydrogen, as water is an almost

inexhaustible renewable source and the water

splitting process is not as energy-intensive as steam

reforming. However, in order to achieve a high water

splitting efficiency, an electrocatalyst for the

hydrogen evolution reaction (HER) is crucially needed

to render a high current at low overpotentials.

Platinum (Pt) has so far been the most efficient and

commonly used electrocatalysts for HER. But it is not

practical and economically viable to use Pt for large-

scale application because of its high cost and scarcity.

Therefore, developing earth-abundant and low cost

HER catalysts having comparable activity and stability

as Pt is highly desired [1]. Very recently, transition

metal phosphides (TMPs), such as Ni2P, CoP, MoP,

FeP, etc., have emerged as a new class of catalysts

which show sufficiently high electrocatalytic activity

and excellent stability toward HER in acidic

electrolytes [2,3].

In this work, we report a facile route to the growth

of nickel phosphide (Ni2P) nanoneedles on

commercially available nickel (Ni) foam, which

involves direct phosphorization of Ni foam under

solvethermal conditions using red phosphorous as a

precursor [4]. This results in the formation of well-

defined Ni2P nanoneedles on the entire surface of

the Ni foam (see Figure 1a). The electrocatalyic

performance of the as-fabricated Ni2P/Ni electrode

was evaluated by linear scan voltammetry (LSV) and

electrochemical impedance spectroscopy (EIS) in 0.5

M H2SO4. A cathodic current as high as 42 mA cm-2

was observed at an overpotential of 200 mV, and to

afford a current density of 20 mA cm-2

only a small

overpotential of 162 mV is needed (see Figure 1b).

The EIS result reveals that the charge transfer

resistance of the Ni2P nanoneedles is 143.2 Ω, close

to that of the Pt foil (104.4 Ω). Moreover, the

Ni2P/Ni also exhibits reasonably good stability due to

the protection of a continuous Ni12P5 layer

underneath the nanoneedles. The observed good

electrocatalytic performance of the Ni2P/Ni can be

attributed to the unique 3D porous feature of the Ni

foam, which is not only beneficial for the mass

transfer of the electrolyte and release of H2 gas

bubbles, but also greatly facilitates the electron

transport in the overall electrode. The Ni2P

nanoneedles supported on Ni foam reported in this

work hold substantial promise for use as efficient

and low-cost cathodes in electrolyzers.

R e f e r e n c e s

[1] Morales-Guio, C. G., Stern, L. A., Hu, X. L.

Nanostructured hydrotreating catalysts for

electrochemical hydrogen evolution, Chem. Soc.

Rev. 43 (2014) 6555-6569.

[2] Popczun, E. J., McKone, J. R., Read, C. G.,

Biacchi, A. J., Wiltrout, A. M., Lewis, N. S.,

Schaak, R. E. Nanostructured nickel phosphide

as an electrocatalyst for the hydrogen evolution

reaction, J. Am. Chem. Soc. 135 (2013) 9267-

9270.

[3] Liu, Q., Tian, J. Q., Cui, W., Jiang, P., Cheng, N. Y.,

Asiri, A. M., Sun, X. P. Carbon nanotubes

decorated with CoP nanocrystals: A highly

active non-noble-metal nanohybrid

electrocatalyst for hydrogen evolution, Angew.

Chem. Int. Ed. 126 (2014) 6828-6832.

[4] Wang, X.G., Ko’lenko, Y., Liu, L.F. Direct growth

of nickel phosphide nanoneedles on nickel foam

for efficient electrocatalytic hydrogen evolution,

under preparation


F i g u r e s

Figure 1: (a) A representative SEM image showing the nickel

phosphide nanoneedle arrays grown on the ligament of the nickel

foam and (b) comparison of the polarization curve of NiP/Ni with

that of the Ni foam and Pt foil recorded in 0.5 M H2SO4 at a scan

rate of 10 mV s-1

.


Dmitri Yerchuck Heat-Mass Transfer Institute of National Academy of

Sciences of RB, Brovka Str.15, Minsk, 220072, Belarus

N e w Q u a n t u m P h y s i c s

P h e n o m e n a i n O p t i c a l a n d

R a d i o S p e c t r o s c o p i e s

Brief review of the discoveries of new quantum

physics phenomena in optical spectroscopy and

radiospectroscopy is presented. They are the

following

1. The phenomenon of ferroelectric spin wave

resonance, on which was reported for the first time

in 2008, represents itself the optical analogue of

ferromagnetic spin wave resonance.

2. It is especially interesting, that the detailed study

of the phenomenon of ferroelectric spin wave

resonance in quasi-1D carbon-based materials -

carbynoids - has led to the discovery of dually

charged quasiparticles, possessing by both electric

and magnetic charge components. It has been

found, that the experimental value of the ratio of

imagine (magnetic) to real (electric) complex charge

components of dually charged quasiparticles is in

the range of predictions of the theory, developed by

Dirac for pointlike particles.

3.The phenomenon of antiferroelectric spin wave

resonance, on the discovery of which was reported

for the first time in 2009, is also the optical analogue

of the corresponding magnetic phenomenon -

antiferromagnetic spin wave resonance.

4. The existence of own electric spin moment, that

is, electric analogue of own magnetic spin moment,

mathematically predicted by Dirac, by which can

possess some quasiparticles in condensed matter,

was confirmed for the first time. It is the result of

detailed study of the phenomenon of

antiferroelectric spin wave resonance in carbynoids.

5. A new quantum optics phenomenon – the

quantum Rabi oscillations' formation and

propagation in space, predicted theoretically by

Slepyan, Yerchak, Hoffmann, Bass, - has

experimentally been identified for the first time in

carbon nanotubes, incorporated in diamond single

crystals, in carbynoid films, and in graphene. It is the

consequence of strong electron-photon coupling,

and it leads to the appearance of additional lines in

stationary optical spectra, corresponding to Fourier

transform of the revival part of the time

dependence of integral inversion of coupled qubits.

It was reported in 2012.

6. The phenomenon of ferrimagnetic spin-wave

resonance [uncompensated antiferromagnetic spin-

wave resonance] has been detected and reported

for the first time quite recently, in 2014.

7. Peculiarities of ferrimagnetic spin-wave resonance

allowed to insist on the formation in nanotubes

incorporated in diamond single crystals in [100]

direction of s+-superconductivity at room

temperature, coexisting with uncompensated

antiferromagnetic ordering, that is, the new kind of

superconductivity mechanism, realizing in magnetic

resonance conditions, was identified.

The discovered phenomena seem to be substantial

for the applications in nanotechnology, for instance,

for quantum informatics, quantum computing and

for the elaboration of various quantum devices,

especially realized on carbon nanonotubes

aforeindicated or carbynoids, which are found being

to be multiferroic materials.


Inês M. Pinto

International Iberian Nanotechnology Laboratory,

Braga, Portugal

[email protected]

E p i t h e l i a l T u m o r D y n a m i c s :

N a n o c h a r a c t e r i z a t i o n o f

f o r c e - g e n e r a t i n g s t r u c t u r e s

The International Iberian Nanotechnology

Laboratory (INL) is an international organization

created to foster interdisciplinary research in

Nanotechnology and Nanosciences. The main goal

of the Laboratory is to undertake ground-breaking

scientific research in specific areas such as

nanomedicine.

At NanoPT2015, we present one of our projects

aiming the development of biomechanical-based

markers for early diagnosis of epithelial tumors, by

combining tools and concepts from different fields:

quantitative cell imaging analysis, genetic

engineering, nanoscale reconstituted systems and

biophysical modelling. The innovative nature of

this project will likely impact the development of

selective anticancer drugs and novel methods for

therapy control.

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Mechanosynthesis and Spark Plasma Sintering of Fine-Grained Na1/2Bi1/2Cu3Ti4O12 Ceramics with Giant Dielectric Response

Mohamad M. Ahmad

Department of Physics, College of Science, King Faisal University, Al-Asia, Saudi Arabia

[email protected]

Abstract Materials with high values of the dielectric constant are technologically important for their use in various microelectronics applications, such as the components involved in charge storage capacitors. Giant dielectric constant (GDC) was discovered in the ACu3Ti4O12 (ACTO) family of materials, where A = Ca, La2/3, Y2/3, Bi2/3, Na0.5Bi0.5, etc, with CaCu3Ti4O12 (CCTO) is the most studied example material [1-3]. These materials, with the perovskite structure, exhibit dielectric values up to 4-105 that is almost independent of temperatures and frequencies over wide ranges [1-3]. The observed (GDC) is due to internal barrier layer capacitance (IBLC) effects that originate from the presence of semiconducting grains separated by resistive grain boundaries [2,3]. The GDC oxide materials are usually prepared by solid state reaction followed by conventional sintering, leading to coarse grained ceramics. It is widely accepted that the dielectric permittivity will increase with increasing the grain size from few to hundreds m [4]. However, we have reported recently that CCTO nanoceramics with grain size in the 100 200

nm exhibit GDC similar to the coarse grained ceramics [5]. In the current work we study the dielectric response of fine-grained Na0.5Bi0.5Cu3Ti4O12 (NBCT) ceramics.

NBCT was synthesized by mechanosynthesis at RT using stoichiometric proportions of Na2CO3, Bi2O3, CuO and TiO2. The milling process was performed in Fritsch P-7 machine using tungsten carbide pots and balls, where the balls to powder mass ratio was 8:1. The milling process continued for 30 h with a rotation speed of 450 rpm. NBCT ceramics were obtained by SPS at 800, 850 and 900 °C using SPS 4-10 system (Thermal Technology LLC). The SPS experiments were performed in a 20 mm graphite die under 60 MPa pressure with a heating rate of 150 °C/min and the dwelling time was fixed to 10 min followed by rapid cooling. The product materials were characterized by XRD and FE-SEM techniques. Impedance measurements were conducted in the 120 400 K temperature range over the 1 Hz 40 MHz frequency range using Novocontrol concept 50 system.

XRD patterns of the SPS ceramics in Fig. 1(e) show the formation of the perovskite structure of the NBCT ceramics. SEM micrograph [Fig. 1(a-d)] of the mechanosynthesized powder shows that nanopowder with particle size < 50 nm was obtained. The grain size of the SPS ceramics increased to 250-450 nm with increasing the SPS temperature from 800 to 900 °C. The grain size of the current ceramics is one order of magnitude smaller than that obtained by conventional sintering. The frequency dependence of the dielectric constant of SPS-900 ceramics is shown in Fig. 2(a). At low frequencies, a plateau region exists with a dielectric value of ~ 3.0 x 104. At high frequencies the dielectric constant drops to a value of ~ 200, which represent the bulk response. The frequency dependence of the dielectric constant of SPS-800, SPS-850 and SPS-900 ceramics at 300 K is shown in Fig. 2(b). We notice that all the NBCT fine-grained ceramics hive very similar dielectric values. This is a result of the close grain size of the investigated materials. The transport properties of the current ceramics are studied though impedance spectroscopy. The impedance diagrams for SPS-900 ceramics are shown in Fig. 3(a). In this figure two semicircles are observed; a large one at the low frequency side, which is due to grain boundary contributions and a high frequency semicircle which is assigned to the bulk response. The temperature dependence of the grain and grain boundary conductivity is presented in Fig. 3(b). We notice that the grain conductivity is much larger than the grain boundary conductivity, supporting the IBLC model. However, the grain boundary conductivity in the SPS NBCT ceramics is very high (~ 2.7 x 10-3 S/cm at 300 K) compared to the ceramics prepared by conventional sintering with a value of ~ 5 x 10-6 S/cm [6]. The activation energy of the grain conduction is 0.089 eV, which agrees with the other ACTO GDC materials. However, the activation energy of the grain boundary contribution is 0.192 eV, which is much smaller than the value of ~ 0.5 0.6 eV that usually reported for GDC materials.

References [1]M. A. Subramanian, D. Li, N. Duan, B. A. Reisner, and A. W. Sleight, J. Solid State

Chem., 151 (2000) 323. [2]D. C. Sinclair, T. B. Adams, F. D. Morrison, and A. R. West, Appl. Phys. Lett., 80 (2002) 2153. [3]M. C. Ferrarelli, T. B. Adams, A. Feteira, D. C. Sinclair, and A. R. West, Appl. Phys. Lett., 89 (2006)

212904. [4]T. B. Adams, D. C. Sinclair, and A. R. West, Adv. Mater., 14 (2002) 1321. [5]M. M. Ahmad, Appl. Phys. Lett., 102 (2013) 232908.

[6]H. Ren, P. Liang and Z. Yang, Mater. Res. Bull., 45 (2010) 1608.

Inte

nsity

(A

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807060504030202

SPS-900 SPS-850 SPS-800

(e)

Figure 1. SEM micrographs of (a) NBCT nanopowder and (b-d) SPS-800, SPS-850 and SPS-900, respectively. (e) XRD patterns of SPS NBCT ceramics.

5

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(a)

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(b)

Figure 3. (a) frequency dependence of the dielectric constant for (a) SPS-900 sample and (b) for all ceramics at 300 K.

-6

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-4

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-2

-1

log

dc (

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m)

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Figure 4. (Left graph) Complex impedance diagrams for SPS-900 ceramics at different temperatures. The inset shows the impedance of the grains at high frequencies. (Right graph)) The temperature dependence of the grain (closed squares) and grain boundary (closed circles) conductivities of SPS-900 ceramics.

Functionalized Solid Lipid Nanoparticles: a theranostic approach for the treatment of Rheumatoid Arthritis

João Albuquerque, Catarina Costa Moura, Bruno Sarmento, Salette Reis

REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto,

Rua de Jorge Viterbo Ferreira n.º 228, 4050-313 Porto, Portugal joao.albuquerque,[email protected]

Abstract

Rheumatoid Arthritis (RA) is the most common autoimmune disease related to the joints and one of

the most severe. Despite the intensive investigation, RA inflammatory process remains unknown and

finding effective and long lasting therapies that specifically target RA is a challenging task. In RA the

pro-inflammatory macrophages persist in the inflammation site and frequently overexpress cytokines

and other biomolecule factors that amplify even more the inflammatory process. However, during RA,

the macrophages also overexpress the CD64 surface marker that drives the search for new specific RA

therapies.

This work proposed an innovative approach for RA therapy, taking advantage of the new emerging

field of nanomedicine and the tools that it offers for targeted therapies. This study aimed to develop a

targeted theranostic system for intravenous administration, using Solid Lipid Nanoparticles (SLN), a

biocompatible and biodegradable colloidal delivery system, widely researched for medical applications,

to function as a drug delivery system. The SLNs were encapsulated with methotrexate (MTX) and

superparamagnetic iron oxide nanoparticles (SPIONs), to be used as therapeutic and imaging agents,

respectively. The SLNs were also surface-functionalized with an anti-CD64 antibody that specifically

targets RA-infected macrophages.

A total of eight different cetyl palmitate and stearic acid SLN formulations were produced using in an

organic solvent-free emulsification-sonication method that combined high shear homogenization and

ultra-sonication in order to compare the influence of each component present (MTX, SPIONs and anti-

CD64) on NP characteristics. Particle size was assess by dynamic light scattering and analyzed by

transmission electron microscopy and surface charge (zeta potential) mas measured by phase analysis

light scattering. The placebo formulations showed sizes around 160 nm and zeta potentials of 40 mV.

Results also showed that MTX did not influence significantly NP properties, whereas SPIONs

encapsulation caused an increase in both size and zeta values. The antibody conjugation caused an

increased in zeta potential as expected but an unexpected decrease in NP size was observed.

However, all the formulations presented sizes below 200 nm and zeta values lower than -12 mV,

indicating suitable characteristics as nanosystems for intravenous administration. The stability of these

formulations was also proven up to one month for the non-conjugated formulations. Nanoparticle

morphology was analyzed by transmission electron microscopy (TEM).

TEM photographs indicated that the SPIONs were encapsulated inside the SLN matrix. Also, it was

possible to observe small deformity and aggregation of NPs, while formulations without SPIONs

presented a spherical shape with little aggregation. FT-IR was used to confirm the presence of MTX in

the SLNs as well as the successful conjugation of the antibody to the SLN. MTX association efficiency

was determined by UV/Vis spectrophotometry, rendering values non-lower than 98% for both MTX-

loaded SLNs and MTX- and SPIONs-loaded SLNs.

In vitro studies were performed with THP-1 cells and enabled to assess the cytotoxicity of the

developed formulations. MTT and LDH assays demonstrated that the formulations were biocompatible

and presented low cytotoxicity a concentrations lower than 500 µg/mL, but there were no significant

changes when comparing the different formulations at the same concentrations unexpectedly.

This study could provide an effective and viable approach for future theranostic strategies. It was

proven that the proposed NP were not cytotoxic, that both a therapeutic and imaging agent could be co-

encapsulated and the SLN functionalized for a potential future application such as anti-body specific

targeting. The proposed formulations are, therefore, promising candidates for future theranostic

applications.

Figures

Figure 1 Schematic representation of the proposed theranostic strategy for the treatment of RA.

Surpassing NSAIDs side-effects with Lipid Nanoparticles

Araújo J., Neves, A. R., Gouveia, V., Moura, C., Nunes, C. and Reis, S.

REQUIMTE, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto Rua de Jorge Viterbo Ferreira n.º 228, 4050-313, Porto, Portugal

[email protected] The inflammatory process is the innate immune response for the presence of pathogens, toxic molecules, tissue injuries or any other harmful conditions. The inflammation process is characterized for redness, pain, swelling, heat and disturbance of function and comprises inducers, sensors, mediators and effectors components from cellular and humoral origin. Macrophages are one of the most important cells in the inflammatory process. Macrophages actively phagocyte particles with sizes superiors to 200 nm and express folate receptor making them of great interest for passive and active targeting strategies. Non-Steroidal Anti-Inflammatory Drugs, like oxaprozin, are one of the most used drugs prescribed for these conditions, however these drugs have adverse side effects, namely at the level of the gastric mucosa, that must be avoided and pharmacokinetic properties that need to be improved and for these purpose many delivery systems arise. Lipid Nanoparticles allow an effective drug packaging and targeted delivery, improving drug´s pharmacokinetics and pharmacodynamics properties and avoiding some of their side effects. In this work, two formulations containing oxaprozin were developed: nanostructured lipid carriers with and without folate functionalization obtained by the addition of a synthesised DSPE-PEG2000-FA conjugate. These formulations revealed high stability, low polydispersity and mean diameters that allowed macrophages passive targeting along with high encapsulation and loading capacity. The formulations avoided the oxaprozin release in simulated gastric fluid promoting its release on simulated intestinal fluid, physiologic and inflammatory medium, remaining only a small amount entrapped on the lipid carrier matrix. MTT and LDH assays revealed that the formulations only seemed to present cytotoxicity in Caco-2 cells, for oxaprozin concentratipermeability studies in the same cell line shown that oxaprozin encapsulation on the lipid nanoparticles did not interfere with oxaprozin permeability.

Targeting of Plasmodium transmission stages with polymers-FITC for future antimalarial delivery strategies

Joana Marques

1, Michael Delves2, Ursula Straschil2, Elisabet Martí1, Elisabetta Ranucci3, Paolo Ferruti3, Robert Sinden2, Xavier Fernàndez-Busquets1

1. Institute for Bioengineering of Catalonia, Barcelona Centre for International Health Research,

Centre Esther Koplowitz planta 1, Rosselló 149-153, E08036 Barcelona, Spain 2. Sinden Lab, Imperial College, 6th Floor SAF Building, South Kensington, London, SW7 2AZ, UK 3. Department of Chemistry, Università degli Studi di Milano, Via Golgi 19, IT-20133 Milano, Italy

[email protected]

With malaria elimination now firmly on the global research agenda, but resistance to the currently available drugs on the rise, there is an urgent need to invest in the research and development of new antimalarial strategies(1). Drugs can potentially target a suite of parasite life stages inside two different hosts: the human and the mosquito vector.

Asexual blood stages are responsible for all symptoms and pathologies of malaria, and therefore resident parasites inside Plasmodium-infected RBCs (pRBCs) are the main target for current chemotherapeutic approaches(2). As there can be several hundred billion pRBCs in the bloodstream of a malarious person it is nearly impossible to clear infections with single-dose administrations. Multiple doses are required instead and this continuous exposure to drugs increases the likelihood for resistance to develop, which will rapidly decrease treatment efficacy. This is prompting research oriented to target bottlenecks in the parasite life cycle, i.e. the pathogen population consisting of a few individuals in certain transmission stages from the human host to the insect and vice versa(3,4,5), which will reduce the probability of resistance emergence(6).

Although the innate immune system of mosquitoes is capable of completely clearing a malaria infection(7), it is far from the sophisticated arsenal providing long-term protection in mammalian adaptive immunity. This might result in parasite stages with reduced defenses because they only need to survive for a few weeks inside the insect facing an immune surveillance not as demanding as in the human host. Drugs targeting early Anopheles stages must kill only ca. 5 x 103 parasites to free a mosquito from Plasmodium infection(8), and the absolute low corresponds to oocysts, of which there are only 2-5 in a single insect(5) and which are around for over a week.

Previous results obtained by our group indicated that certain polymers can have a dual role as antimalarial drugs and as targeting elements towards pRBCs(9,10). Thus, we explored if these polymers could also be targeting agents against the Plasmodium mosquito stages (gametocytes, sporozoites, ookinetes, and oocysts).

This work was supported by grants BIO2011-25039 from the Ministerio de Economía y

Competitividad, Spain, which included FEDER funds; 2009SGR-760 from the Generalitat de Catalunya, Spain; Xarxa Eurolife from Universitat de Barcelona; and 2013-0584 from the Fondazione CARIPLO, Italy. References 1. Alonso PL , Tanner M: Public health challenges and prospects for malaria control and elimination. Nat.Med. 19(2), 150-155 (2013).

2. Griffith KS, Lewis LS, Mali S, Parise ME: Treatment of malaria in the United States: a systematic review. JAMA 297(20), 2264-2277 (2007).

3. Sinden R, Carter R, Drakeley C, Leroy D: The biology of sexual development of Plasmodium: the design and implementation of transmission-blocking strategies. Malar.J. 11(1), 70- (2012).

4. Delves MJ, Ramakrishnan C, Blagborough AM, Leroy D, Wells TNC, Sinden RE: A high-throughput assay for the identification of malarial transmission-blocking drugs and vaccines. Int.J.Parasitol. 42(11), 999-1006 (2012).

5. Delves MJ: Plasmodium cell biology should inform strategies used in the development of antimalarial transmission-blocking drugs. Future Med.Chem. 4(18), 2251-2263 (2012).

6. Delves M, Plouffe D, Scheurer C et al: The activities of current antimalarial drugs on the life cycle stages of Plasmodium: a comparative study with human and rodent parasites. PLoS Med. 9(2), e1001169-e1001169 (2012).

7. Marois E: The multifaceted mosquito anti-Plasmodium response. Curr.Opin.Microbiol. 14(4), 429-435 (2011).

8. Sinden R: A biologist's perspective on malaria vaccine development. Hum.Vaccin. 6(1), 3-11 (2010).

9. Marques J, Moles E, Urbán P et al: Application of heparin as a dual agent with antimalarial and liposome targeting activities towards Plasmodium-infected red blood cells. Nanomedicine: NBM 10, 1719-1728 (2014).

10. Urbán P, Valle-Delgado JJ, Mauro N et al: Use of poly(amidoamine) drug conjugates for the delivery of antimalarials to Plasmodium. J.Control.Release 177, 84-95 (2014).

Figure 1. Targeting assay of the 5 polymers in study to Plasmodium berghei ookinetes. Polymers labelled with FITC were added to living cultures of P. berghei ookinetes and incubated for 90 minutes before sample preparation for microscopic analysis. Each series shows ookinetes (arrowheads) and pRBCs (arrows) as control of the specificity of the targeting. Scale bars correspond to 10 µm.

Water-Dispersible Silver Nanoclusters: Synthesis and Characterization

José M. Blancoa, Javier Calvod, Enrique Carbó Argibaya, Erea Borrajo Alonsoc, Fernando Domínguezc,

M. Arturo López Quintelab, and José Rivasa,b

aInternational Iberian Nanotechnology Laboratory, 4715-330 Braga-Portugal bLaboratorio de Magnetismo y Nanotecnología, Instituto de Investigaciones Tecnológicas, Universidad

de Santiago de Compostela, E-15782, Santiago de Compostela, Spain cInstituto de Investigación Sanitaria de Santiago de Compostela (IDIS), 15706 Santiago de Compostela,

Spain dNanogap, 15895 Milladoiro, A Coruña, Spain

Abstract We report here a route to synthesize small water-dispersible silver nanoclusters (also known as Atomic Quantum Clusters - AQCs) in the absence of any type of surfactant or stabilizing agent, through an easy and versatile potentiostatic method based on a bottom-up electrochemical synthesis of nanoparticles1. The small size of the nanoclusters, comparable to Fermi wavelength of the electron (~0.52 nm for silver), places AQCs in the scale range where quantum confinement effects govern the material properties. Because of this, AQCs behave like molecules, displaying delocalized molecular orbitals, similar to those observed in HOMO and LUMO orbitals of single molecules, and exhibiting new and interesting physical and chemical properties derived from their small size, such as photoluminescence2,3 or magnetism4,5. The stability, biocompatibility and fluorescence of silver AQCs allow to apply them in very different fields, such as catalysis, biosensing and nanomedicine. In fact, results about the biological activity of silver sub-nanometric quantum clusters will be shown here. Different techniques were employed in order to characterize the structure of the synthesized silver nanoclusters, such as spectroscopy (UV-Vis, Fluorescence), mass spectrometry (ESI Electrospray Ionization), atomic force microscopy (AFM) and electrochemical techniques as for example cyclic voltammetry (CV).

300 400 500

0.00

0.02

0.04

0.06

Ag 2-3

Abso

rban

ce/U

A

nm

Ag 4-7

a)

300 400 500 600

0.0

4.0x106

8.0x106

Ag2

Ag7

Ag6

Ag5

Ag4

I/U

E

nm

Exc 230nm Exc 270nm Exc 310nm Exc 330nm Exc 350nm

Ag3

b)

Fig 1. Characterization by Absorption and Fluorescence spectrophotometer of a sample of silver AQCs. a) UV-Vis absorption spectrum, b) Emission spectra measured at exciting wavelengths between 230 and 350 nm. Acknowledgement: this work is supported by POCTEP (Operational Programme for Cross-border Cooperation Spain-Portugal), co-financed by the ERDF (European Regional Development Fund) under grant InveNNta Project. 1 Manfred, T. Reetz; Wolfgang Helbig., J. Am. Chem. Soc., 116 (16) (1994) 7401 7402. 2 Schaeffer, N.; Tan, B.; Dickinson, C.; Rosseinsky, M. J.; Laromaine, A.; McComb, D. W.; Stevens, M. M.; Wang, Y.; Petit, L.; Barentin, C.; Spiller, D.G.; Cooper, A. I.; Levy, R., Chem. Commun., (2008) 3986. 3 Haekkinen, H., Chem. Soc. Rev, 37 (2008) 1847. 4 Moro, R.; Yin, S.; Xu, X.; de Heer, W. A., Phys Rev Lett., 93 (2004) 086803. 5 Ledo-Suarez, A.; Rivas, J.; Rodriguez-Abreu, C.; Rodriguez, M. J.; Pastor, E.; Hernandez-Creus, A.; Oseroff, S.B.; Lopez Quintela, M. A., Angew. Chem. Int. Ed., 46 (2007) 8823.

Work Function and Gate Length Effect On Electrical Characteristics Of n-FinFET in 3D

Using ATLAS SILVACO

N. Boukortt

1,2,*, B. Hadri1, L. Torrisi2, S. Patanè2, A. Caddemi2 & G. Crupi2

1 University of Mostaganem, Avenue Hamadou Hossine, Mostaganem, Algeria 2 Universita` degli studi di Messina, V. F.S. d'Alcontres 31, 98166 s. Agata, Messina, Italy

* [email protected]

Abstract

This work investigates the threshold voltage, subthreshold slope and leakage current sensitivity to metal

gate work function and gate length for a n-channel fin field-effect transistor (FinFET) in a 3-D structure

using the numerical simulation tool Atlas Silvaco. Silvaco-Atlas was used to construct, examine and

simulate the structure and characteristics of the FinFET device in three dimensions. Results were

analyzed and presented to show that the threshold voltage is reduced with the decrease in gate work

function and gate length. The behavior of the subthreshold slope and the leakage current improves with

increased metal gate work function. The SCE in FinFET 3-D can reasonably be controlled and improved

by proper adjustment of the metal gate work function. The obtained results also show that when there is

a reduction of gate length the subthreshold slope decreases and leakage current increases giving a

good saturation region in output characteristics (Ids-Vds). Simulation shows possible scaling to 8 nm gate

length.

Keywords: Device Scaling, FinFET, Silicon On Insulator "SOI", work function, gate length, Silvaco

Software.

References

[1] Jean-Pierre Colinge, Springer Science & Business, (2007) 1-37. [2] M. Mustafa, Tawseef A. Bhat, M. R. Beigh, World Journal of Nano Science and Engineering, 3

(2013) 17-22. [3] Olivier Ezratty, Las Vegas Convention Center SOUTH HALLS - Ligaran (2014) p.289. [4] S K Mohapatra , K P Pradhan and P K Sahu, Transactions On Electrical And Electronic Materials, 14

(2013) 291-294. [5] C. Hu, Prentice Hall, (2010) 195-258. [6] S. K. Mohapatra, K. P. Pradhan and P. K. Sahu, International Journal of Advanced Science and

Technology, 65 (2014) 19-26. [7] Ahlam Guen and Benyounes Bouazza, International Journal of Science and Advanced Technology,

2 (2012) 40-45. [8] V. Narendar, Ramanuj Mishra, Sanjeev Rai, Nayana R and R. A. Mishra, International Journal of

VLSI design & Communication Systems, 3 (2012) 175-191. [9] Neeraj Gupta; A.K. Raghav; Alok K. Kushwaha, International Journal OF Technological Exploration

And Learning, 3 (2014) 455-458. [10] Yongho Oh and Youngmin Kim, Journal of Electrical Engineering & Technology, 1 (2006) 237-240. [11] Abhinav Kranti and G Alastair Armstrong, Semicond. Sci. Technol, 21 (2004) 409-421. [12] I. Flavia Princess Nesamani, Geethanjali Raveendran, Dr.V. Lakshmi Prabha, International Journal

of Engineering Trends and Technology, 4 (2013) 299-301. [13] Nagaratna Shanbhag, Kiran Bailey, Dr. K.S. Gurumurthy, International Journal of Science,

Engineering and Technology Research, 3 (2014) 1381-1386

Figures

Fig 1. n-FinFET structure. Fig 3. IDS-VGS characteristics on log scale.

Fig 2. IDS-VGS characteristics On linear scale.

Fig 4. IDS-VDS characteristics. Fig 4. IDS-VGS characteristics on linear scale.

Fig 4. IDS-VGS characteristics on log scale.

Fig 4. . Threshold voltage versus gate work function.

Fig 4. . Leakage current versus gate work function.

Fig 4. IDS-VGS characteristics on log scale.

Fig 4. Threshold voltage versus gate length.

Fig 4. Subthreshold slope versus gate length.

Fig 4. Leakage current versus gate length

Low-temperature conversion of titanate nanotubes into nitrogen-doped TiO2 nanoparticles

,1 Henrik Haspel,1 1,2 1,2,3

1Department of Applied and Environmental Chemistry, University of Szeged, Rerrich r 1, H-6720 Szeged, Hungary

2MTA- H-6720 Szeged, Hungary

3MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, H-6720 Szeged, Hungary

[email protected] Abstract

In the past two decades nanotubes have become the symbol of nanotechnology, a new and fast evolving field of science. Inorganic nanotubes with trititanate structure (NaxH2-xTi3O7) were first synthesized by Kasuga and coworkers. Their intention was to obtain TiO2 with high specific surface area and enhanced photocatalytic activity. However, the applied alkaline treatment gave rise to morphological changes and tubular nanostructures with diameter of ~8 nm and length of ~100 nm appeared in the samples. Many possible applications of titanate nanotubes are known nowadays: high surface area mesoporous catalyst support, adsorbent, insoluble matrix for ion-exchange processes etc. They are used in the development of lithium-ion batteries, in medical biology and are promising candidates for heterogeneous photocatalysis as well.

In our study titanate nanotubes were synthesized via the alkaline hydrothermal procedure. After a subsequent protonation step the obtained nanotubes were doped with nitrogen using ammonia formed in situ by the thermal decomposition of urea. This new method is an economic low temperature alternative to the existing gas phase N-doping procedures. Different nitrogen doping times were applied to the samples, followed by calcination steps at various temperatures, while changes in the morphology and phase were investigated. To this end, transmission and scanning electron microscopic (TEM, SEM), energy dispersive X-ray spectroscopic (EDS), X-ray and selective area electron diffraction (XRD, SAED) measurements were performed.

The increase in the nitrogen content and calcination temperature induced changes in the size and shape of the nanotubes, along with the transformation of the crystal structure. Nanotubes were first converted into anatase and then into rutile TiO2. The initial tubular morphology collapsed, and at low temperatures nanorods, while at higher temperatures nitrogen doped isometric nanoparticles were formed [1]. References [1] Buchho , Z. CrystEngComm, 16 (2014) 7486 7492. Figures

Morphology and crystalline phase variation of nitrogen-doped titanium-oxide nanostructures with

nitrogen doping and calcination temperature.

Metabolic effects of silver nanoparticles assessed by NMR metabolomics of mice liver and serum

Joana Carrola1, Ivana Jarak1, Rui Silva1, António S. Barros2, Ana M. Gil1, M. Lourdes Pereira1, M.

Luisa Corvo3, Iola F. Duarte1

1CICECO, Departamento de Química, Universidade de Aveiro, Portugal 2QOPNA, Departamento de Química, Universidade de Aveiro, Aveiro, Portugal

3iMed.ULisboa,Departamento de Farmácia Galénica e Tecnologia Farmacêutica, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal

[email protected]

Abstract Silver nanoparticles (Ag-NPs) are among the nanomaterials with highest propensity for human exposure, arising from their established use in wound dressings and increasing incorporation into consumer products (e.g. clothing, food packaging), mainly due to their remarkable antimicrobial properties. However, there is a narrow window between the bactericidal activity of Ag-NPs and their toxicity to human cells1, making the further understanding of their biological effects a relevant up-to-date subject. Development of metabolic profiling (metabolomics) strategies for assessing the cellular and systemic effects of these nanoparticles may provide a unique and important tool that can be broadly applied in the areas of nanotoxicology and nanomedicine2.

In this work, male mice were randomly divided into three groups, a control group (n 10) and two experimental groups (n 5 each) i.v. administered with Ag-NPs suspensions (1 mg/mL) and sacrificed at 24 and 48 hours post-injection. A complete necropsy was conducted on all mice. The necropsies included, but were not limited to, examination of the external surface, the cranial, thoracic, abdominal and pelvic compartments, including viscera. Liver, spleen, heart and kidneys were collected, rinsed with physiological serum and weighted. Tissue histopathology parameters and complete haemogram were also assessed. Based on a preliminary biodistribution study, liver tissues and blood serum were collected for metabolic profiling analysis. In particular, the samples were analysed by 1H Nuclear Magnetic Resonance (NMR) spectroscopy, using High Resolution Magic Angle Spinning (HRMAS) for direct tissue analysis, and the spectral data subjected to multivariate analysis, namely Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA), to highlight the metabolic differences between the groups. The livers of control and Ag-NPs-exposed mice showed several significant differences in their metabolic composition, already apparent by simple visual inspection of 1H HRMAS spectra (Figure 1A). Indeed, control and exposed groups showed a trend for separation in the PCA scores scatter plot and were clearly discriminated by PLS-DA (Figure 1B). The main metabolic alterations explaining this separation were in the levels of glucose, glycogen and reduced glutathione (decreased in exposed animals compared to controls) and in the levels of choline compounds and taurine (increased in mice exposed to nanoparticles for 24 and 48h, respectively). In regard to serum NMR profiles, while the most apparent alterations were in the levels of lipoprotein subclasses (Figure 2A), several other differences could be found in small metabolites, including increased levels of amino acids (alanine, valine, lysine, histidine, tyrosine, phenylalanine), creatine, choline and glycerol, together with decreased levels of glucose, acetate and fumarate. Interestingly, most of these changes showed a stronger magnitude at 24h than at 48h of Ag-NPs exposure, which explains the time-dependent group separation observed in the PCA and PLS-DA scores plots (Figure 2B). Overall, the results show that Ag-NPs, at a sublethal dose, disturb cellular and systemic metabolism, mainly affecting pathways involved in energy production and antioxidant protection. References [1] Kim S and Ryu DY, J. Appl. Toxicol., 33 (2013) 78. [2] Duarte IF, J. Control. Release 153 (2011) 34.

Figures Figure 1. A) Average 1H HRMAS NMR spectra of liver tissue from control mice (top), and mice exposed to Ag-NPs for 24h (middle) and 48h (bottom). B) Scores scatter plots obtained by PCA and PLS-DA of NMR liver spectra ( exposed 24h; exposed 48h). Figure 2. A) Average 1H NMR spectra of blood serum from control mice (top), and mice exposed to Ag-NPs for 24h (middle) and 48h (bottom). B) Scores scatter plots obtained by PCA and PLS-DA of NMR serum spectra ( exposed 24h; exposed 48h).

Glucose

Triglycerides

5.00 4.00 3.00 2.00 1.00 ppm

ppm

Choline compounds

Glycogen

PCA

PLS-DA

A B

ppm

HDL

LDL/ VLDL

Alanine

Glucose Choline

Creatine

Acetate

4.50 4.00 3.50 3.00 2.50 2.00 1.50 1.00 ppm

PCA

PLS-DA

A B

FRET based gold nanobeacon for sequence discrimintation

Mílton Cordeiro1,2

, Pedro Viana Baptista1, João Carlos Lima

2

1REQUIMTE,Departamento de Química, Faculdade de Ciências e Tecnologia, UniversidadeNOVA de Lisboa. Campus da Caparica, 2829-516 Caparica, Portugal.

2Nanomedicine@FCT, UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa. Campus da Caparica, 2829-516 Caparica, Portugal.

!

[email protected]

Abstract

We report development of a gold nanoparticle (AuNP) molecular beacon based biosensor

coupled to a wavelength shift mediated by FRET, for the detection of fusion transcripts

associated with the development of Chronic Myeloid Leukemia. Citrate capped 14 nm gold

nanoparticles were functionalized with thiolade polyethylene glycol and further functionalized with

a donor fluorophore labeled ssDNA with a hairpin structure. In the absence of a complementary

target, the donor is in close proximity to the surface of the gold nanoparticle, leading to its

quenching - gold nanoparticle are know to be fluorescence modulators [1-2]. Upon hybridization

to the target sequence the donor breaks away from the surface of the gold nanoparticles due to

the disruption of the hairpin structure, leading to a partial restoration of the donor fluorescence.

The disruption of the hairpin leads to the exposure of the palindromic sequence, allowing the

hybridization of an acceptor labeled oligonucleotide – See figure 1. With the donor and acceptor

in such proximity, FRET occurs leading to a wavelength shift of the hybridization fluorescence

signal to wavelengths that are not affect by the high absorption of the AuNP.

References

[1] Lakowicz J. R., Radiative decay engineering 5: metal-enhanced fluorescence and plasmon emission, Anal. Biochem., 337: 171–194[2]- Rosa J., Lima J. C., Baptista P. V.,Experimental photophysical characterization% of fluorophores in the vicinity of gold nanoparticles, Nanotechnology,22:415202(7pp)(2011)

!

!

Figure 1. Schematic representation of the FRET based Au-nanoprobe. In the absence of a complementary target, the hairpin is in its closed conformation. Upon addition of complementary target (1), the closed conformation of the hairpin is disrupted and the donor breaks away from the surface of the AuNP, exposing the palindromic sequence that can hybridize to the acceptor labeled oligonucleotide (2).

Mechanosynthesis of supersaturated ternary solid solutions (FeCo)100-xSnx and their ordering by annealing at low temperature

B. F.O. Costa1, B. Malaman

2 and G. Le Caër

3

1 CEMDRX, Physics Department, University of Coimbra, P-3004-516 Coimbra, Portugal 2 Institut Jean Larmour, Départment P2M, Equipe 103, CNRS (UMR7198)- Université de Nancy, B.P.

70239, F-54506 Vandoeuvre-les-Nancy Cedex, France 3 IPR, UMR URI-CNRS 6251, Université de Rennes I, Campus de Beaulieu, Bat 11A, F-35042 Rennes

Cedex, France [email protected]; [email protected]; [email protected]

Abstract

Iron-cobalt alloys have exceptional magnetic properties and are mechanically relatively strong [1]. Near-equiatomic FeCo alloys are bcc (A2) below ~1250K [1]. They order to a CsCl type structure (B2) at temperatures below ~1000K. A possible way to study alloys which tend to order is to prepare them by high-energy ball-milling HEBM from mixtures of elemental powders [2]. The as-milled alloys aregenerally in a metastable disordered state and may be ordered by annealing at well-chosen temperatures. We investigated recently the synthesis of metastable ternary alloys (FeCo)100-xSnx (x~ 0- 33 at%) by HEBM [3, 4, 5]. The ternary system Fe-Co-Sn is essentially uninvestigated. The equilibrium solubility of Sn in FeCo (A2 or B2) is ~ 1 at% [6].

Milling of powder mixtures of Fe, Co and Sn was performed in argon atmosphere using a planetary Fritsch Pulverisette P6 mill. Alloys were annealed at 673K for 15h in quartz tubes sealed under vacuum. The evolution of the alloying process and the annealed alloys were characterized by X- ray and neutron diffraction and by

57Fe and

119Sn Mössbauer spectroscopy.

X-ray diffraction patterns of ground powders show the presence of nanocrystalline disordered bcc phases (grain size ~4-8 nm). The lattice parameter a(x) increases steadily with Sn content till x 25 in a way fully consistent with the dissolution of Sn in FeCo as discussed in [3, 4, 5]. For alloys with Sn contents of 25 and 33 at% bcc Fe-Co-Sn alloys coexist with nanocrystalline hexagonal Co3Sn2 (see too figure 1). The maximum solubility of Sn in near-equiatomic Fe-Co is thus less than 25 at% Sn in our milling conditions, being of the order of 20 at% Sn.

Figures 1 and 2 present room temperature (RT) 57

Fe and 119

Sn Mössbauer spectra of as-milled alloys (FeCo)Snx (10h milling) and those of as-milled alloys annealed at 673K for 15h. Figure 3 shows the RT hyperfine magnetic field distributions (HMFD), P(H), of Fe44Co44Sn12 milled for 10h and then annealed at 673K for 15h. Neutron diffraction patterns are displayed in Figure 4 for (FeCo)100-xSnx (6 x 25) alloys milled during 10h and then annealed at 673K for 15h.

The average 57

Fe HMF decreases when the Sn content increases in the as-milled state (fig. 1 left). The decrease is much less for annealed alloys (4x20) and the widths of the HMFD’s are smaller for the annealed alloys (fig. 1 right). For x=12 (fig. 3 right) the average

57Fe HMF’s are 31.7 T and 32.7 T

in the as-milled and annealed alloy respectively. The 57

Fe HMF’s are not very sensitive to chemical order in these alloys. By contrast, the

119Sn HMF’s show a strong sensitivity to chemical order when

dissolved in B2 FeCo (~0.3 at.%Sn) [6]. The HMF is about 25 T for Sn atoms which sit on the Co sublattice while it is as small as 0.7 T for those which sit on the Fe sublattice [6]. Figures 2 and 3 show that the

119Sn spectra vary strongly when the as-milled alloys are annealed at 673K. For x=12 (fig. 3 left)

the average 119

Sn HMF increases from 9.8 T to 16.3 T between the as-milled and the annealed states. The maximum

119Sn HMF (fig. 3), 24.5 T, is close to the value measured for Sn dissolved in perfectly

ordered FeCo [6]. The ordering by annealing shown by 119

Sn Mössbauer spectra is confirmed by neutron diffraction patterns (fig. 4) which evidence clearly the presence of (100) and (111) superlattice lines.

In summary, the maximum solubility of Sn in FeCo is considerably increased by HEBM. In our milling conditions the latter increases from ~1 at.% at thermal equilibrium to ~20 at. %. The metastable as-milled alloys are bcc and disordered. They order by annealing at moderate temperatures (here 673K) for any Sn content less than 20 at.%.

References [1] T. Sourmail, Prog. Mater. Sci. 50 (2005) 816 . [2] C. Suryanarayana, Prog. Mater. Sci., 46 (2001) p.1 [3] J.M. Loureiro, B.F.O. Costa and G. Le Caër, J. Alloys Comp 536S (2012) p.S31 [4] J.M. Loureiro, B.F.O. Costa, G. Le Caër and B. Malaman, Solid State Phenom 194 (2013) p.187 [5] J.M. Loureiro, B.F.O. Costa, B. Malaman, G. Le Caër, S. Das and V.S. Amaral, J. Alloys Comp 615 (2014) p.S559 [6] N.N. Delyagin and E.N. Kornienko, Sov. Phys. Solid State 13 (1971) p.1254

NanoPT2015 February 11-13, 2015

Figures

Figure 1- RT 57

Fe Mössbauer spectra of mechanically alloyed (FeCo)Snx: as-milled (left) and annealed at 673K (right)

Figure 2- RT 119

Sn Mössbauer spectra of mechanically alloyed (FeCo)Snx: as-milled (left) and annealed at 673K (right)

Figure 3- RT hyperfine magnetic field distributions (

119Sn:

left, and 57

Fe: right) of (FeCo)88Sn12 alloy, as-milled and annealed

Figure 4- Neutron diffraction patterns of (FeCo)100-xSnx (6 x 25) alloys milled during 10h and then annealed at 673K for 15h.

NanoPT2015 February 11-13, 2015

Nanofabrication of Magnetic Tunnel Junction Pillars Targeting Nano-Oscillator

Applications J. D. Costa1,2, E. Paz1, J. Borme1, S. Serrano1, J. M. Teixeira2, J. Ventura2, R. Ferreira1, P. P. Freitas1,3

1 International Iberian Nanotechnology Laboratory, INL, Avenida Mestre José Veiga, 4715-330 Braga,

PORTUGAL; 2 IN-IFIMUP, Rua do Campo Alegre 687, 4169-007 Porto, PORTUGAL; 3 INESC-MN and IN- Institute of Nanoscience and Nanotechnology, Rua Alves Redol, 9-1, 1000-029 Lisbon, PORTUGAL

[email protected]

Abstract Magnetic Tunnel Junctions are Spintronic devices constituted by two ferromagnetic layers

separated by a nanometric insulating barrier. The theoretical predictions of giant Tunnel

Magnetoresistance (TMR) values in fully crystalline Fe(001)/MgO(001)/Fe(001) structures [1]

were soon followed by its experimental verification [2,3]. Such giant TMR effect arises from

the conservation of the coherence of the electron wave function during tunneling across

crystalline MgO and from the smaller decay rate of the spin up states in the barrier when

compared to that of spin down states (spin filtering effect) [4]. In state of the art CoFeB-MgO

MTJs, TMR ratios of up to 600% have been reported [5]. In the low resistance x area (RA) range, which is the most important for applications, TMR values of 138% have been

2 (in unpatterned MTJs) [6].

These results promptly widened the prospect of fabricating novel magnetic devices that operate

using spin transfer torque (STT) mechanisms. This effect consists in the transfer of the moment

of magnetic spins from a polarized electrical current to the ferromagnetic layers, thus allowing

the manipulation of the magnetization of nano-magnets by means of local currents in

opposition to magnetic fields. Two of the best positioned STT applications to reach the

commercialization in the short term are RF emitters resulting from persistent magnetic

dynamics driven by DC currents and non-volatile magnetic random access memories.

In order to achieve high quality STT devices the downscaling of MTJs until dimensions below

100 nm is necessary. In this presentation we will describe our nanofabrication process which is

mainly based in e-beam lithography and ion milling steps. Several problems arise from the

miniaturization of the MTJs being one of the most prominent the material re-deposition on the

sidewalls of the nanopillars during the ion beam etching. This re-deposition inflates the final

device critical dimension. More importantly, it causes the electrical shunting across the barrier

which decreases the TMR. To remove the material re-deposition a low angle milling is usually

used after the normal milling definition. However, low angle millings create damages in the

device edges, generate shadowing effects that prevent the formation of vertical sidewalls and

decrease the process uniformity due to clamps used at wafer edges. The edge damage can be

minimized by using a low beam energy milling. However, the divergence of the beam increases

for lower beam energies and thus a compromise must be found. Another problem related to the

nanofabrication process consists in conferring mechanical stability to the devices while

keeping the nanopillars open on top. This structure enables the microfabrication of the

remaining components of the device that allow the reading/writing of the MTJ. To achieve this

structure a dielectric material is deposited after the nanopillar definition and afterwards

opened on the top of the pillars. In order to open the MTJs, processes based on lift-off and

chemical-mechanical processes (CMP) have been used. Despite the simplicity of the lift-off

process, the yield of the open nanopillars is relatively low and it has a process time that can go

up to two weeks. Moreover, the process is intrinsically worse for smaller nanopillars. As for the

CMP process, it is a very fast process that opens more easily the smaller pillars. However,

there are a lot of residues arising from the planarization and a good uniformity is difficult to

achieve.

Here, we also propose the use of an ion beam planarization step after the nanopillar

definition. This process is faster than the lift off and cleaner that CMP and intrinsically better

for the smaller pillar sizes. Using the described process we were able to achieve MTJs with RA

below 1.5 2 and TMR up to 130%. We will also give a general overview of the different

devices fabricated, such as the double barrier MTJs, magnetic vortexes and MTJs with

perpendicular magnetic anisotropy. References

[1] Spin-dependent tunneling conductance of Fe/MgO/Fe sandwiches, W.H. Butler, X.-G.

Zhang, T.C. Schulthess, and J.M. MacLaren, Phys. Rev. B 63, 054416 (2001),

[2] Giant tunnelling magnetoresistance at room temperature with MgO (100) tunnel barriers,

S.S.P. Parkin, C. Kaiser, A. Panchula, P.M. Rice, B. Hughes, M. Samant, and S.-H. Yang, Nat.

Mater. 3, 862 (2004),

[3] Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel

junctions, S. Yuasa, T. Nagahama, A. Fukushima, Y. Suzuki, and K. Ando, Nature Mater. 3, 868

(2004),

[4] Giant tunnel magnetoresistance in magnetic tunnel junctions with a crystalline MgO(0 0 1)

barrier, S. Yuasa and D.D. Djayaprawira, J. Phys. D 40, R337 (2007),

[5] Tunnel magnetoresistance of 604% at 300 K by suppression of Ta diffusion in

CoFeB/MgO/CoFeB pseudo-spin-valves annealed at high temperature, S. Ikeda, J. Hayakawa,

Y. Ashizawa, Y.M. Lee, K. Miura, H. Hasegawa, M. Tsunoda, F. Matsukura, and H. Ohno,

Appl. Phys. Lett. 93, 082508 (2008).

[6] In situ heat treatment of ultrathin MgO layer for giant magnetoresistance ratio with low

resistance area product in CoFeB/MgO/CoFeB magnetic tunnel junctions, S. Isogami, M.

Tsunoda, K. Komagaki, K. Sunaga, Y. Uehara, M. Sato, T. Miyajima, M. Takahashi, Appl.

Phys. Lett. 93, 192109 (2008).

The role of TiO2 nanoparticles and photocatalytic processes in the treatment

of industrial effluents.

J.O. Carneiro a, A. P. Samantilleke a, P. Partpot b, C Tavares a, F. Fernandes a, M. Pastor a, A.

Correia a, V. Teixeira a

a Department of Physics, University of Minho, Azurém Campus, 4800-058, Guimarães, Portugal

b Department of Chemestry, University of Minho, Azurém Campus, 4800-058, Guimarães, Portugal

In recent years, new textile materials have been developed using nanotechnology-based tools.

These have been extensively investigated for use in various scientific and technological fields. This

multidisciplinary methods of changing surface has become thus an essential step in order to

combine different physical and chemical properties for obtaining a multifunctional material. The

development of self-cleaning textile surfaces with combined properties has a great potential for

reducing environmental impact related pollution caused by effluents and its versatility in application

to any geometry.[1] [2]

The release of untreated wastewater, primarily from textile industries as well as sewage in

rivers and lakes stimulate serious ecosystem imbalances that, if not addressed can escalate to

create conditions that threaten human health. The need for versatile materials, which reduce or

minimize the effect of hazardous compounds is growing rapidly. . In this context, the photocatalytic

activity of nanomaterials based on titanium dioxide (TiO2) in textile applications has been identified

as a strategic vector with a considerable industrial impact. [3]

The heterogeneous photocatalysis is potentially a powerful technological tool for various

applications Titanium dioxide is by far the most applied material,in photocatalitic processas due to

its availability in the crust, high chemical stability, high oxidation power, low toxicity and low cost [4].

The techniques of deposition of TiO2 particles in a liquid phase have attracted considerable

interest, as such matrials and technques are with low production cost and relative ease of industrial

implementation. [5]

The implementation and use of photocatalityc textiles in environmental remediation has a

high relevance directly related with their contact area. Titanium dioxide was applied by a

mechanical process called padding in this work. The textiles werefully characterized in order to

investigate whether they retainthe initial properties while the surface maintaining self-cleaning

abilities. The samples of textiles were subjected to hot wash tests to assessthe adhesion of

nanoparticles.

References

[1] Vinu R, Madras G. Environmental remediation by photocatalysis 2010;90.

[2] Meilert KT, Laub D, Kiwi J. Photocatalytic self-cleaning of modified cotton textiles by TiO2 clusters attached by chemical spacers. J Mol Catal A Chem 2005;237:101 8.

[3] Dalton C. J.P. Smol, Pollution of lakes and rivers: a paleoenvironmental perspective, 2nd edition. J Paleolimnol 2009;42:301 2.

[4] Diebold U. The surface science of titanium dioxide. Surf Sci Rep 2003;48:53 229.

[5] Fujishima A, Zhang X. Titanium dioxide photocatalysis: present situation and future approaches. Comptes Rendus Chim 2006;9:750 60.

Exfoliation of graphite using pyrene and perylene derivatives

Eunice Cunha

1, M. Conceição Paiva1, M. Fernanda Proença2, Rui Araújo2

1 Instituto de Polímeros e Compósitos/I3N, Universidade do Minho, Campus de Azurém, 4800-058 Guimarães, Portugal

2Centro de Química, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal

[email protected]

Abstract Since the isolation of graphene by mechanical exfoliation of graphite in 2004 [1] this material has been the focus of research among the scientific community. The excellent electronic, mechanical, thermal and optical properties of graphene [2] have reveled huge potential applications in various fields such as energy storage, [3,4] composite materials [5] and sensor technology [6]. However, the production of graphene in large scale, with controlled quality and reasonable cost, is still a goal to achieve and became an important target and research topic. The large scale graphene production processes are based on the conversion of SiC (silicon carbide) to graphene via sublimation of silicon at high temperature, chemical vapor deposition (CVD) growth, oxidation of graphite followed by exfoliation and reduction of the oxidation products, and exfoliation of graphite in organic solvents with high surface tension. These methods lead to large scale production, but present some disadvantages namely the high cost, or the production of graphene with structural defects or contaminants which are difficult to remove. [7] Some aromatic compounds such as pyrene and perylene derivatives, functionalized to render them amphiphilic, have been reported to effectively stabilize carbon nanotubes in aqueous suspensions. [8,9] Recently, the production of graphene based on graphite exfoliation through non-covalent interactions between graphene/pyrene and graphene/perylene derivatives was also reported.[10] This approach promotes the exfoliation and stabilization of graphene in water, leading to the production of few- and single- layer graphene without damaging its structure. The present work reports the preparation of stable aqueous suspensions of few-layer graphene using low concentration solutions of pyrene and perylene derivatives. The suspensions were analyzed by UV-Visible spectroscopy. The graphene-based materials deposited on surfaces were analyzed by Raman spectroscopy, showing the effectiveness of the exfoliation of pristine graphite. TEM images of the suspensions illustrate the formation of few layer graphene. Figure 1a presents the Raman spectra of graphite and few-layer graphene obtained by exfoliation with a pyrene derivative (Py-XGnP), and Figure 1b illustrates the TEM observation of the Py-XGnP. Acknowledgement We gratefully acknowledge FCT for PhD grant SFRH/BD/87214/2012 and Post-doc grant SFRH/BPD/88920/2012. References [1] K. Novoselov, A. Geim, S. Morozov, D. Jiang, Y. Zhang, S. Dubonos, I. Grigorieva and A. Firsov, Science, 306 (2004) 666-669. [2] A. Geim and K. Novoselov, Nature Materials, 6 (2007) 183-191. [3] M. Stoller, S. Park, Y. Zhu, J. An and R. Ruoff, Nano Letters, 8 (2008) 3498-3502 [4] S. Ghosh, X. An, R. Shah, D. Rawat, B. Dave, S. Kar, S.Talapatra, Physical Chemistry C, 116 (2012) 20688 20693. [5] H. Kim, A. Abdala and C. Macosko, Macromolecules, 43 (2010) 6515 6530. [6] X. Zhang, F. Gao, X. Cai, M. Zheng, F. Gao, S. Jiang and Q. Wang, Materials Science and Engineering C, 33 (2013) 3851 3857. [7] V. Singh, D. Joung, L. Zhai, S. Das, S. Khondaker and S. Seal, Progress in Materials Science, 56 (2011) 1178 1271. [8] T. Fujigaya and N. Nakashima, Polymer Journal, 40 (2008) 577 589. [9] R. Araújo, C. Silva, M. C. Paiva, M. Melle Franco and M. F. Proença, RSC Advances, 3 (2013) 24535-24542. [10] D. Parviz, S. Das, H. Ahmed, F. Irin, S. Bhattacharia, and M. Green, ACS Nano, 6 (2012) 88578867

Figure 1: a) Raman spectra of pristine graphite (XGnP) and exfoliated graphite using pyrene derivative (Py-XGnP); b) TEM image of Py-XGnP (on the left), magnified TEM Image (on the right) and XRD pattern of magnified Py-XGnP TEM image.

1000 1500 2000 2500 3000

Inte

nsity

(a.u

.)

Raman Shift (cm-1)

Py XGnP

XGnP

a)

b)

Nanocomposite materials for shaping the diffusive transport of light

André Espinha,a María Concepción Serrano,b Álvaro Blanco,a Cefe Lópeza

aInstituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Calle Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain

bHospital Nacional de Parapléjicos, Finca de la Peraleda, s/n, 45071 Toledo, Spain [email protected]

Abstract In the photonics community, disordered materials are being explored more and more due to their particular way to interact with light [1]. Typically, they are composed of non-absorbing building blocks with sub-micrometric size, distributed in a random way. As so, their refractive index is a complex function of position and light undergoes multiple scattering [2] thus, the transport is diffusive. If the scattering efficiency is equal for the whole visible electromagnetic spectrum, they present a white, milky aspect. Not only they are very rich systems which exhibit challenging phenomena for physical interpretation, but also several research areas with social impact and industrial potential have emerged, ranging from random lasers to imaging through opaque media, for example. Nanocomposites, formed by an optically functional phase embedded in a processable matrix, are a very versatile platform for developing optical applications [3] and, in this way, may be used for producing diffusive systems. We would like to present our latest achievements in the field, which have been aimed at engineering the transport of light (specifically the transport mean free path) in nanocomposites based on multifunctional polymers presenting shape memory effect [4]. Different parameters such as the concentration of scatters or the temperature could be acted on in order to design materials which are almost transparent or, on the contrary, highly opaque. We believe that our results might pave the way for more systematic investigations with potential impact on intelligent light sources with improved energy efficiency or new kinds of actuators. This work was partially supported by EU FP7 NoE Nanophotonics4Energy grant No. 248855, the Spanish MICINN project MAT2012 31659 (SAMAP), and Comunidad de Madrid S2009/MAT-1756 (PHAMA) program. A.E. was supported by the FPI Ph.D. program from the MICINN. M.C.S. acknowledges Instituto de Salud Carlos III - MINECO for a Miguel Servet contract (CP13-00060). References [1] D. S. Wiersma, Nature Photonics, 7 (2013) 188. [2] B. Van Der Mark, M. P. Van Albada, A. Lagendijk, Physical Review B, 37 (1988) 3575. [3] L. Beecroft, C. Ober, Chemistry of Materials, 9 (1997) 1302. [4] M. Behl, M. Razzaq, A. Lendlein, Advanced Materials, 22 (2010) 3388.

Synthesis and optical properties of CdSe nanoparticles in PVK semiconducting polymer

J.C. Ferrer, S. Fernández de Ávila, J.L. Alonso

Área de Electrónica, Universidad Miguel Hernández, Av. Universidad, s/n, Elche (Spain) [email protected]

Abstract

Semiconducting nanocrystals, or quantum dots, exhibit interesting properties like size-dependent photoemission wavelength over a wide spectral range and high photoluminescence quantum yields [1]. Blends of polymer solutions and nanocrystals in colloidal suspension are very attractive from the point of view of device fabrication since the resulting nanocomposite material combines the optical properties and robustness of inorganic particles with the ease of processing and flexibility of polymers [2,3]. Poly(N-vinylcarbazole) (PVK) is a hole transport polymer exhibiting an emission spectrum that, owing to the properties of carbazole groups, covers the entire blue region. CdSe is an II-VI semiconductor with a 1.74 eV bandgap which is suitable for integration in optoelectronic devices operating in the visible wavelength range. Based on the method reported in [4] we have performed the synthesis of CdSe nanocrystals capped with Fluorothiophenol (ShPhF) e dissolved in 10 ml of methanol and 308 mg of Cd(NO3)2 2O were dissolved in 2 ml of water and 8 ml of methanol. The Cd(NO3)2 solution was added to the SHPhF solution resulting in a white precipitate according to the following reaction:

The precipitate was washed with methanol and centrifuged three times. The washed precipitate was vacuum dried and the resulting powder was analyzed by X-ray photoelectron spectroscopy with a Phi 5500 ESCA system, which confirmed the chemical composition of the powder. The Cd(FC6H5S)2 complex contains both the cadmium atoms for the subsequent CdS synthesis and the organic molecule for the capping. 52 mg of the Cd(FC6H5S)2 powder was dissolved in 20 ml of dimethyl sulfoxide (DMSO) and 0.1 ml of a elemental Se 0.1% solution in toluene were added to the Cd(FC6H4S)2 resulting in an optically clear yellow solution indicating the formation of CdSe quantum dots. Bright yellow fluorescence of this

remained stable during months showing no change in luminescence intensity and wavelength. The synthesis of the CdS nanocrystals using the Cd(FC6H4S)2 complex has a major advantage compared to other cadmium salts: the molecule contains both the cadmium atoms and the organic radical for the capping leaving no residual after reaction with elemental selenium. Three blends of CdSe quantum dots and PVK 0.3% in toluene were obtained by mixing different volumes of the respective solutions according to the following proportions: 25% vol. PVK : 75% vol. CdSe, 50% vol. PVK : 50% CdSe and 75% vol. PVK : 25% vol. CdSe (samples 1:3, 1:1, 3:1 respectively). An aliquot of the starting CdSe nanocrystal and PVK solutions were kept for reference purposes (samples 0:1 and 1:0 respectively). Transmission electron microscopy (TEM) images were obtained with a Philips CM30 microscope operating at 300 kV. The absorbance spectra were recorded with a Shimadzu UV-1603 spectrometer. TEM images of the quantum dots prior to the mixing with the polymer were obtained in order to determine the size and the quality of the nanoparticles. The images show isolated nanoparticles with an average size about 4 nm. Since the Bohr radius of CdSe is about 5 nm [1], we expect to observe the effects of the quantum confinement in the optical characterization measurements. Photoluminescence (PL) spectra were obtained by means of a Photon Technology International fluorimeter. The optical absorption of the nanocomposite solution as well as the reference samples is presented in fig. 1. The spectrum of the pure quantum dot solution (sample 0:1) shows an excitonic peak at an

indicates that strong quantum confinement has been achieved, as expected from the TEM observations.

HS F FSF Cd SCd (NO3)2

The absorption spectrum of the bare PVK solution (sample 4:0), depicted in the same figure, shows an

increasing absorbance of the excitonic peak related to the quantum dots as the amount of CdSe is increased (samples 1:3, 2:2, 3:1). Photoluminescence (PL) measurements of the reference samples and blends were performed using an excitation wavelength at 370 nm. The recorded spectra are presented in fig.3. The luminescence spectrum of the pure PVK solution (sample 4:0) is dominated by a peak located at 3.1 eV (400 nm) while the pure quantum dot solution sample (0:4) shows a broad peak found at 2.42 eV (513nm). The PL spectra of the blends display the characteristics of the emission from the two species. Note that although the PVK intensity decreases gradually as the PVK amount is reduced, the intensity change of the CdSe peak is weaker compared to that of PVK. This observation could be related to a Förster-type energy transfer from PVK to CdSe [5]. This kind of energy transfer requires an overlap between the emission spectrum of donor and the absorption spectrum of the acceptor. In our case, the overlap is evident since the PL peak of the polymer is located at 3.1 eV and the excitonic peak of the nanocrystals has a maximum at 3.06eV. Thus, this diluted nanocomposite shows the potential to be used as active layer for optoelectronic devices. References [1] A.D. Yoffe, Adv. Phys., 50, (2001) 1. [2] W. Caseri, Macromol. Rapid Commun., 21, (2000) 705. [3] E. Holder, N. Tessler and A.L. Rogach, J. Mater. Chem.,18 (2008), 1064. [4] I.G. Dance, A. Choy and M.L. Scudder, J. Am. Chem. Soc.. 106 (1984) 6285. [5] F. Teng, A. Tang, B. Feng and Z. Lou, Appl. Surf. Sci., 254 (2008) 6341. Figures

Fig. 1. Optical absorption spectra of pure CdSe nanocrystal (0:4), pure PVK (4:0) and blends of 25% PVK:75% CdSe (1:3), 50% PVK:50% CdSe (1:1) and 75% PVK:25% CdSe (3:1).

Fig. 2. PL spectra of pure CdSe nanocrystal (0:4), pure PVK (4:0) and blends of 25% PVK:75% CdSe (1:3), 50% PVK:50% CdSe (1:1) and 75% PVK:25% CdSe (3:1).

Modification of optical properties of polymer films by addition of PbS nanoparticles

S. Fernández de Ávila, J.C. Ferrer, J.L.Alonso and B. Rakkaa

Departamento de Ingeniería de Comunicaciones, Universidad Miguel Hernández, Edificio Innova, Avda. de la Universidad s/n, Elche, 03202 Alicante, Spain

[email protected]

Abstract

Semiconductor nanoparticles have attracted the interest of many research groups for the last two decades. As the diameter of a semiconductor crystal approaches its exciton Bohr diameter, the electronic properties of the semiconductor start to change. This is known as the quantum size effect. It is commonly observed that as the particle size decreases the optical absorption edge shifts to higher energy (blue-shift) [1].By doping organic materials with these nanoparticles a variety of nanocomposite materials can be prepared with customizable optical and electrical properties. These nanocomposites are especially interesting if they can be easily synthesized and processed at low cost. In particular, those composites processed from solution that can be cast by simple techniques, such as different printing technologies, drop-casting or spin-coating among others.Polymers have proved to be a useful matrix in assembling the nanoparticles, improving their stability and helping to control the size of the semiconductor nanoparticles [2].In this study we use the well known poly[2-methoxy-5-(3’,7’-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) semiconducting polymer as matrix, and we will synthesize lead sulfide (PbS) nanoparticles (NPs) directly in it by using a very simple synthetic route.Assuming that optical properties of semiconductor nanoparticles can also be modified by surface chemical modification, 1,4-fluorothiophenol (SHC6H4F) was always used to cap the NPs for the experiment reported here.Pb(SPhF)2 complex is prepared by reaction of Pb(NO3)2 and SHC6H4F. This complex contains the Pb

and the capping radical for the PbS NPs, and it is soluble in dimethylsulfoxide (DMSO). Addition of asmall volume of sulfur to this precursor solution produced PbS NPs capped with the organic radical.This reaction is shown in figure 1 [3].To prepare the nanocomposite a whole batch of solutions containing MDMO-PPV and Pb(SPhF)2

complex were dissolved using 4:1 toluene:DMSO solvents ratio. PbS nanoparticles are synthesized by adding a solution of sulfur in toluene to the polymer-complex solution. Changing the volume of sulfur added to each solution the amount of PbS nanoparticles synthesized inside the polymer can be modified.The presence of these PbS NPs has been checked by TEM measurements as can be seen in figure 2.Optical properties of thin films prepared by spin casting from nanocomposite solutions with increasing PbS NPs loading, have been studied.Quenching of PL emission is observed when the ratio of PbS NPs increases with respect to the polymer suggesting the occurrence of Dexter energy transfer from the polymer to the PbS NPs. An enhancement of optical absorption is found for nanocomposites with increasing PbS NPs concentration [4]. Optical absorption is markedly increased for nanocomposite films compared to pure polymer film suggesting its potential application in optoelectronic devices such as solar cells.We demonstrate that optical properties of MDMO-PPV polymer film can be modified by addition of PbS

nanoparticles.

References

[1] Y. Wang, A. Suna, W. Mahler, and R. Kasowski, The Journal of Chemical Physics, vol. 87, no. 12 (1987) 7315.[2] S. Kango, S. Kalia, A. Celli, J. Njuguna, Y. Habibi, and R. Kumar, Progress in Polymer Science, vol. 38, no. 8 (2013) 1232.[3] J. C. Ferrer, A. Salinas-Castillo, J. L. Alonso, S. Fernández de Avila, and R. Mallavia, MaterialsChemistry and Physics, vol. 122 (2010) 459.[4] S. Fernández de Ávila, J.C. Ferrer, J.L. Alonso, R. Mallavia and B. Rakkaa. Journal of Nanomaterials Volume 2014, Article ID 671670 (2014) 1-7.

Figures

Figure 1: PbS nanoparticles capped with 1,4-fluorothiophenol (SHC6H4F) can be obtained by reaction of Pb(SPhF)2 complex with a small amount of sulphur.

Figure 2: TEM image of an ensemble of PbS NPs within the polymer matrix

Optimization and characterization of lipid-based nanoparticles for topical therapy of psoriasis

Mara Ferreira1,2, Sofia A. Costa Lima1, Salette Reis1

1REQUIMTE/ Department of Chemistry, Faculty of Pharmacy, University of Porto,Rua de Jorge Viterbo Viterbo Ferreira, n.º228, 4050-313, Porto, Portugal

2Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, s/n 4200-465, Porto, Portugal

[email protected], [email protected]

Abstract Psoriasis is a common chronic, autoimmune and systemic inflammatory disease of the skin and joints and occurs in 2 3% of the population. It is characterized by well-demarcated thick erythematous plaques, red and scaly skin which most commonly appears on the elbows, knees, scalp and umbilicus area. Psoriasis is affected by genetic and environmental factors and is associated with co-morbidities counting: loss of quality of life, cardiovascular disease, among others [1 3]. The most important emerging treatments include topical treatments, phototherapy, systemic therapies and biological therapies, employed depending on the severity of the disease [4]. Lipid based carriers could be classified into particulate carriers and this type include solid lipid nanoparticles (SLNs) and nanostructured lipid nanoparticles (NLCs). In particular, NLCs consist of a mixture of solid and liquid lipids that produce nanosized carriers that interact better with skin cells making them very useful for improvement in dermal therapy. In this work, methotrexate was the drug selected for incorporation in the lipid-based nanoparticles as it is the 'gold standard in managing psoriasis' and has the ability to block certain enzymes which are involved in the autoimmune system [4]. The first step of this study was the optimization of some parameters for better development of NLCs in the following main criteria: average particle size between 200-300 nm and encapsulation efficiency of drug higher than 75%. MTX-loaded NLCs were successfully prepared by hot emulsification/ high-shear homogenization using Witepsol E85 and lipid mygliol 812 as lipidic core and poly vinyl alcohol as surfactant. For this combination a 27-run, 3-factor, 3-level Box Behnken design was employed to optimize the process according amount of surfactant, amount of drug and amount of liquid lipid. The characterization was conducted according to their physico-chemical properties such as: particle size, polydispersity index, surface potential and encapsulation efficiency. Size and polydispersity index are evaluated by dynamic light scattering and surface potential throughout a laser Doppler electrophoresis. For the encapsulation efficiency the concentration of non-incorporated MTX was determined by absorption spectroscopy.. The optimized nanoparticles were compared with another type of lipid nanoparticles, the SLNs, to identify the best carrier for MTX for this pathology. The results of the current study warrant further exploration for the use of drug loaded NLCs as a controlled delivery system for topical therapy of psoriasis.

Acknowledgments: This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT) through project Pest-C/EQB/LA0006/2013. This work was also unded by ON.2 QREN - Quadro de Referência Estratégico Nacional QREN, by FEDER funds through the Programa Operacional Factores de Competitividade COMPETE and national funds throught FCT through project NORTE-07-0124-FEDER-000067. The authors would like to acknowledge Excella for kindly provide the MTX.

References

[1] G. K. Perera, P. Di Megl Annu. Rev. Pathol., vol. 7, (2012) pp. 385 422, [2] M. a Lowes, M. Suárez- Annu. Rev. Immunol., vol. 32, (2014) pp. 227 55, [3] J. Berth- Medicine (Baltimore)., vol. 41, (2013) no. 6, pp. 334 340 [4] (2010) pp. 25 37

Cellulose nanofibres obtained by TEMPO mediated oxidation and mechanical treatment: effect of

the mechanical treatment

Jorge F. Pedrosa, Tiago F. Nunes, Ana F. Lourenço, José A. Gamelas, Paulo J. Ferreira*

CIEPQPF, Department of Chemical Engineering, University of Coimbra,

Pólo II, R. Sílvio Lima, P-3030 790 Coimbra, Portugal

*[email protected]

Abstract The size and size distribution of nanofibres is always an important parameter to consider, but it should be mentioned that presently no standard methods or validated techniques are available for the size evaluation of polydisperse nanomaterials with a high aspect ratio [1]. In the present work, four samples of cellulose nanofibers were produced from an eucalypt kraft pulp pre-treated with 15 mmol of NaClO per gram of cellulose and catalytic amounts of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) and NaBr, according to the methodology described by Saito et al. [2]. After the chemical treatment the fibers were subjected to different mechanical treatment intensities during homogenization. Three samples were obtained after passing through the homogeneizer one time (at 500 bar) (1P15R), two times (one at 500 bar and one at 1000 bar) (2P15R) and four times (one at 500 bar and three at 1000 bar) (4P15R). In addition, for control, one sample was left without any mechanical treatment (0P15R). The samples were then characterized in terms of yield of nanofibres production assessed by centrifugation, transmittance of the suspensions in the 400-800 nm visible range (Fig.1), concentration of carboxylic groups determined by conductimetric titration and zeta potential. The size distribution of the material was evaluated by laser diffraction spectroscopy and by dynamic light scattering (Fig.3) of the cellulose nanofibres suspensions (Fig. 2 and 3 respectively). Generally it was concluded that the homogeneization highly increases the amount of nanofibrils but no significant further effects, both in terms of yield and size, are detected with more extensive mechanical treatment. References [1] Fraschini, C., Chauve, G., Le Berre, J- J. Nordic Pulp and Paper Research Journal, 29 (2014) 31-40. [2] Saito, T., Kimura, S., Nishiyama, Y., Isogai, A., Biomacromolecules, 8 (2007) 2485-2491.

Figures

Fig.1- Visible spectra in the transmittance mode.

Fig.2- Volume distributions obtained by laser diffraction spectroscopy.

Fig.3- Intensity distributions obtained by dynamic light scattering.

Characterization of genomic SNP via colorimetric detection using a single gold nanoprobe

Fábio Ferreira Carlos1,2

, Orfeu Flores2, Gonçalo Doria

1, Pedro Viana Baptista

1 1CIGMH, Department of Life Sciences, Faculdade de Ciências e Tecnologia, Universidade Nova de

Lisboa, Campus de Caparica, Caparica, Portugal 2STABVIDA, Investigação e Serviços em Ciências Biológicas, Lda. Madan Parque, Caparica, Portugal

[email protected]

Abstract Identification of specific nucleic acid sequences mediated by gold nanoparticles derivatized thiol-modified oligonucleotides (Au-nanoprobes) has been proven a useful tool in molecular diagnostics [1,3-5]. Here, we demonstrate that, upon molecular optimization, detection may be simplified and results attained using a single Au-nanoprobe to detect SNP in homo- or heterozygous condition (Figure 1). Au-nanoprobes are becoming extremely useful tools for routine molecular diagnostics involving single-base mismatch detection that can be a fast, cheap and reliable alternative to standard techniques [4]. We demonstrate the robustness of this approach through validation using clinical samples and screening for the SNP rs9939609 in the FTO gene locus [2]. For the first time, we demonstrate that, upon comprehensive optimization, a single Au-nanoprobe may be used alone to detect SNP by presenting distinct threshold for each genetic status (wild type, heterozygous and mutant) with high degree of sensitivity (87.50%) specificity (91.67%) [5]. Results were validated using Sanger sequencing as gold standard. Sensitivity, specificity and limit of detection (LOD) were determined and statistical differences calculated by one-way analysis of variance

rtain whether there were any differences between Au-nanoprobe genotyped groups. From the 20 samples genotyped via Sanger sequencing, 8 samples were wild type (T/T), 7 samples heterozygous (T/A) and 5 samples mutated (A/A) [4]. Genotyping using the Au-nanoprobe determined 9 wild type (T/T) samples, 7 heterozygous (T/A) and 4 mutated (A/A). The LOD for Au-nanoprobe FTOwt20 was set at 20 µg ml-1.This simple and fast approach requires low complexity apparatus (UV/Vis spectroscopy) but may also been evaluated by the naked eye. References [1] Baptista P, Pereira E, Eaton P, Doria G, Miranda A, Gomes I, et al, Anal. Bioanal. Chem., 391 2008 943-50 [2] Carlos FF, Silva-Nunes J, Flores O, Brito M, Doria G, Veiga L et al, Diabetes Metab. Syndr. Obes., 11(6) 2013 241-5. [3] Doria G, Franco R, Baptista P, IET Nanobiotechnol., 1(4) 2007 53-7. [4] Doria G, Conde J, Veigas B, Giestas L, Almeida C, Assunção M, Rosa J, Baptista PV, Sensors, 12(2) 2012 1657-1687. [5] Carlos FF, Flores O, Doria G, Baptista PV, Anal. Biochem., 465C 2014 1-5. Figures

Figure 1 Micro Card (Whatman, UK). DNA extraction was carried out for subsequently PCR reactions. After PCR reaction, Au-nanoprobe was mixed with PCR products and a hybridization step was carried out i) after salt addition in the presence of a non-complementary or unrelated PCR a colorimetric change is visible from red to purple after a certain time, ii) after salt addition in the presence of a fully complementary PCR product no colorimetric change is visible and the solution remains red. This color observation can also be observed by UV/Vis spectroscopy.

Simultaneous Delivery of Drugs and Genes by Multi-block Polymeric Nanomicelles for Synergistic Cancer Therapy

Vítor M. Gaspar1, Cristine Gonçalves2, Duarte Melo-Diogo1, Elisabete C. Costa1, João A. Queiroz1, Chantal Pichon2, Fani Sousa1 and Ilídio J. Correia1

1CICS-UBI Health Sciences Research Center, University of Beira Interior, 6200-506, Covilhã, Portugal

2Centre de Biophysique Moléculaire, CNRS UPR4301, Inserm and University of Orléans, 45071 Orléans cedex 02, France

[email protected]

Abstract Presently cancer remains one of the most predominant incurable diseases and it is estimated that its worldwide incidence will continue to increase in the future [1]. From a clinical perspective chemotherapy is one of the best established methodologies for cancer treatment, being generally applied either as first line therapy for early stage disease, or palliative care in later phases. However, the administration of anti-tumoral drugs generally induces systemic cytotoxicity due to their poor selectivity to target cancer cells and tissue partition. Moreover, cancer drug resistance following a multi-stage treatment regime is common and this phenomenon further contributes to the ineffectiveness of chemotherapy. In this context the simultaneous delivery of different anti-tumoral drugs or drug-nucleic acid combinations arises as an exceptionally promising strategy for improving treatment efficacy and overcome cancer drug resistance [2]. Nonetheless, combinatorial therapy is remarkably challenging since nucleic acids are readily degraded in circulation and the simultaneous administration of multiple drugs provokes intolerable cytotoxicity. The use of polymeric micelles is a valuable option to overcome such problems since these nanosized carriers can increase the bioavailability of bioactive molecules, i.e., drugs and genes, in the tumor site by the enhanced permeability and retention (EPR) effect. This characteristic contributes for reducing systemic cytotoxicity and improves treatment efficacy. Also, due to micelles unique hydrophobic-hydrophilic character which self-assembles into a core-shell structure, they can be used as a reservoir for encapsulating hydrophobic anti-tumoral drugs. In turn, this encapsulation promotes a sustained release during an extended time frame and increases intracellular drug concentration. These two parameters contribute for an enhanced therapeutic effect in comparison to standard chemotherapy. Including drug gene combinations is significantly more challenging as the physicochemical nature of these distinct bioactive molecules demands a multi-block co-polymer with both hydrophobic and cationic properties so as to encapsulate drugs and complex DNA at the same time [2]. Thus for co-delivering drugs and nucleic acids the micelles must be self-assembled from polymeric nanomaterials in which the building blocks ought to be specifically tailored to have these properties. Herein we provide, a brief focus on the different biocompatible and biodegradable polymers for micelles self-assembly will be provided. The use of biocompatible micelles for co-delivery of anti-tumoral compounds for cancer therapy will presented. Also, a particular emphasis will be given in the synthesis of innovative tri-block copolymers for gene-drug co-delivery (Figure 1) [3]. The application of this system for the delivery of Doxorubicin and Minicircular DNA (mcDNA) will be presented and the evaluation of its biological performance in vitro and in vivo will be provided. References [1] Rebecca Siegel, Jiemin Ma, Zhaohui Zou and Ahmedin Jemal, CA: A Cancer Journal for Clinitians, 64(1), (2014), 9-29. [2] Vítor M. Gaspar, Cristine Gonçalves, Duarte Melo-Diogo, Elisabete C. Costa, João A. Queiroz, Chantal Pichon, Fani Sousa and Ilídio Correia, Journal of Controlled Release, 189 (2014), 90-104.

Figures

Figure 1. Schematics of gene-drug (minicircle DNA-Doxorubicin) co-delivery concept using multi-block co-polymer micellar carriers.

Strongly anisotropic wetting on highly-uniform self-similar molybdenum nanogrooves

Iaroslav Gnilitskyi

1,*, Ihor Pavlov2, Serim Ilday2, Alberto Rota3, Massimo Messori4, Seydi Yavas2, Leonardo Orazi1 and F. Ömer Ilday2,5

1 - DISMI - Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia,

42100, Reggio Emilia, Italy

2 - Department of Physics, Bilkent University, 06800 Ankara, Turkey

3 - Department of Physics, Computer Science and Mathematics, University of Modena and Reggio Emilia,

41125, Modena, Italy

4 -

5 - Department of Eleckrical and Electronics Engineering, Bilkent University, 06800, Ankara, Turkey

*Corresponding Author e-mail: [email protected],

Nanostructure formation through surface treatment is mostly performed with well-established techniques including lithography and laser-induced periodic surface structuring (LIPSS). However, these techniques suffer either from the limited flexibility, high-cost, complex equipment, or suffer from the low-speed, problems of material control, and lack of uniformity and repeatability over large areas. Recently, a technique called Nonlinear Laser Lithography (NLL) was introduced, which allows fabrication of extremely uniform nanostructures, with excellent long-range repeatability and at high-speeds [1]. NLL can be applied to a variety of materials, including non-planar, even flexible surfaces. While NLL generates essentially LIPPS-type of nanostructures, it does so by utilizing nonlinear feedback mechanisms arising from the interaction of femtosecond laser pulses with the target surface, as well as from the laser-initiated chemical reaction. Key features, such as superior uniformity and ability to process non-flat surfaces are a direct consequence of the self-regulation provided by these feedback mechanisms. Applications of surface-treated nanostructures have been demonstrated in various fields including electronics, optoelectronics, photovoltaics. Although the outcomes are encouraging, because of the problems of material and process control, they are still not suitable for transfer to industrial applications. It is appears that these problems can be overcome by NLL-induced nanostructures, thanks to their aforementioned superior features, with potential for substantial impact in these and related fields. However, the technique is new and its potential for these applications needs to be evaluated systematically. Here, we report on highly uniform, anisotropic, periodic molybdenum nanogrooves fabricated through NLL (Figure 1). We investigate the wettability characteristics of the nanogrooves as a strong candidate to be used for applications where anisotropic wetting of the surfaces is favored, ranging from microfluidics to energy applications to biomedical research such as gas seal conditions, self-cleaning surfaces, directional syringes, microprocessor cooling, high-efficiency hydropower turbines, and nanoscale digital fluidics. Wettability is investigated through contact angle measurements, where sessile drop methodology is used with distilled-deionized water as the test liquid. It is shown that the nanogrooves improved the hydrophilic behavior of the flat molybdenum surface significantly. Moreover, better wetting of the surface along the nanogrooves is observed. It is also shown that we can tune the wettability behavior, where the transition from Wenzel to Cassie regime is observed.

& F. O. Ilday, Nat. Photonics 7 (2013) 897.

Fig. 1. SEM images of the Molybdenum surface ablated by fs-laser pulses at fluence of 0.7 J/cm2. (a)

Nanotextured sample at a 100 mm/s scan speed.(b) Higher magnification image, (c and d) represent higher magnification image of (a), tilted on 45º of (a).(e, f) shows the 2D FFT and 1D FFT images of the micrograph

(b).

Malaria Diagnostics based on Anti- Plasmodium falciparum HRPII Antibody-Functionalized Gold Nanoparticles

Inês Gomes1,2, Eulália Pereira3, Nuno C. Santos1, Maria M. Mota1, Miguel Prudêncio1, Ricardo Franco2

1Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa,

1649-028 Lisboa, Portugal. 2REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de

Lisboa, 2829-516 Caparica, Portugal. 3REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto,

4169-007 Porto, Portugal.

[email protected]

Malaria is a significant health problem in many parts of the world, with an estimated 207 million cases and 627 000 deaths in 2012 mostly among African children. Malaria is caused by five species of parasites in the genus Plasmodium, of which P.falciparum (Pf) is the most prevalent and deadly [1]. Rapid Diagnostic Tests (RDTs) using gold nanoparticles (AuNPs) are alternatives to conventional microscopy-based methods for malaria diagnostics. RDTs are intended to have high reproducibility, acceptable high sensitivity and specificity, rapidity, ease of performance and interpretation, all at an affordable price. AuNPs are ideal candidates for these tests due to their unique nanoscale properties, such as high surface areas, robustness, facile synthesis and functionalization and strong optical absorptions [2]. In this work, gold nanoparticles are functionalized with mercaptoundecanoic acid (MUA) or CALNN pentapeptide. CALNN includes a thiol group (from C) for binding to AuNPs, a hydrophobic region (AL) to promote self-assembly at the AuNP surface, and two uncharged hydrophilic asparagine residues (NN) to interact with an antibody [3]. These functionalized AuNPs are further conjugated with an anti-PfHRPII monoclonal antibody. Conjugation of the monoclonal antibody with the functionalized AuNPs was performed either by electrostatic interactions or by covalent attachment, using the cross-linking agents EDC/NHS. The robustness and binding properties of the bionanoconjugates were evaluated by agarose gel electrophoresis and zeta potential measurements. Results showed the formation of more compact bionanoconjugates in the presence of CALNN and EDC/NHS agents. Increasing concentrations of the antigen were incubated with the bionanoconjugates for two hours. The agarose gel electrophoresis of these antigen-bionanoconjugates showed that electrophoretic mobility decreases with increasing antigen concentrations. These results indicated that it is possible to detect the PfHRPII antigen up to a concentration of 700 µg.mL-1 (Figure 1), opening up the possibility of implementing a simple agarose gel-based method for malaria antigen detection. This new immunoassay will be developed to detect the antigen in malaria-infected in vitro blood cultures. These bionanoconjugates are also being used in the development of a RDT on a nitrocellulose strip or on filter paper, using a competitive assay format. In this assay, the PfHRPII antigen is coated on the test zone of the dipstick, capturing the AuNP-antibody conjugate and allowing the red colour to concentrate and form a spot. This study will constitute an important proof-of-concept for future tests in clinical samples. References [1] WHO, World Health Organization, World Malaria Report 2013. [2] Peixoto de Almeida, M.; Pereira, E.; Baptista, P.; Gomes, I.; Figueiredo, S.; Soares, L.; Franco, R.

, Gold Nanoparticles in Analytical Chemistry, Comprehensive Analytical Chemistry, volume 66, Elsevier, 2014, 530-560. [3] Lévy, R.; Thanh, K. T. N.; Doty, C. R.; Hussain, I.; Nichols, J. R.; Schiffrin, J. D.; Brust, M.; Ferning, G. D. J. Am. Chem Soc., 126, 2004, 10076-10084.

Figures A B [PfHRPII] / [AuNP-CALNN-anti-HRPII]

Figure 1 A. Agarose gel electrophoresis of AuNP-CALNN-anti-HRPII-PfHRPII, using cross-linking agents EDC/NHS. B. Electrophoretic mobility vs. PfHRPII concentration.

Use of Short Amyloidogenic Peptides for Nanotechnology Gabriela M. Guerra, Sónia Gonçalves, Nuno C. Santos, Ivo C. Martins

Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Professor Egas

Moniz 1649-028, Lisbon, Portugal [email protected]

Abstract Amyloid fibers, often associated with several human degenerative diseases (such as

may also have physiological roles, having even been suggested as potential -sheet rich architecture that is

behind their exceptional stability, mechanical strength and resistance to degradation, rendering them excellent nanomaterial candidates [1,2]. The potential to form amyloids (and other protein/peptide aggregates) can be predicted from the peptide sequence [1, 3]. Here, we used atomic force microscopy (AFM), circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) to evaluate which among three possible amyloidosis models (peptides with sequence QVQIIE, ISFLIF and GNNQQNY) would form characteristic amyloid fibrils at physiologic pH conditions. FTIR and CD were used to determine the structural conformation of the amyloid fibrils formed. The CD spectra of QVQIIE are presented in Figure 1A. These spectra demonstrate that this

-sheet conformation characteristic of amyloid fibrils. However, at the pH and temperature conditions tested, the GNNQQNY peptide forms structures with a random coil conformation (Figure 1A), inconsistent with classical amyloid fibril morphology. Due to lower solubility, ISFLIF was prepared at a lower concentration than the other peptide sequences. As at those concentrations the structural characterization of the peptide by CD is not feasible, FTIR was used instead (Figure 1B) -sheet conformation at physiologic pH, with a characteristic band around 1635 cm-1 -sheet peaks are found in the 1623-1640 cm-1 region [4]). From these results it is clear the peptide GNNQQNY, in the conditions tested, does not

-sheet conformation typical of amyloid fibrils. The peptides were further investigated via their abilities to bind Congo Red (a dye commonly used to detect amyloid fibrils in solution [5]). In line with the studies of secondary structure, GNNQQNY does not bind Congo Red. Congo Red binding assays of ISFLIF and QVQIIE are presented in Figure 1C. In the presence of amyloid fibrils, Congo Red absorbance spectrum changes, resulting in a maximal spectral difference at 540 nm [5]. QVQIIE spectra did not suffer these characteristic maximal spectral differences, indicating that amyloid fibrils are not formed at the pH and temperature incubation conditions. ISFLIF, however, suffers a clear shift, indicative of amyloid structure. Having established the peptides secondary structure content, AFM was employed in the subsequent studies, as it is a microscopic technique very useful for the study of amyloid fibrils because it allows the imaging of surfaces with high resolution and sensibility (Figure 1D). Negative and positive controls behaved as expected. GNNQQNY does not form amyloid-like structures, while QVQIIE shows structures that are not consistent with classic well-structured mature amyloid fibrils. Regarding ISFLIF, this peptide clearly forms an amyloid fibril structure, similar to the positive control. AFM-based morphological characterization of the ISFLIF amyloid fibrils (Figure 1E-F) shows that these fibrils have and average diameter of 159.6 ± 3.2 nm and 10.0 ± 0.1 nm of average height. ISFLIF amyloid fibrils formed under these physiological conditions of pH and temperature seem to be similar to standard amyloid fibrils, constituting promising biomaterials [1, 2]. AFM, CD, FTIR and Congo Red data, taken together, indicate the peptide ISFLIF as the most reproducible and amenable peptide for developing amyloid-based nanotechnology approaches, in line with previous work [2, 3], where short amyloidogenic peptides are sought for nanotechnology applications. References [1] Cherny I and Gazit E, Angew Chem Int Ed Engl, 47 (2008) 4062 [2] Hauser C A E., Maurer-Stroh S, Martins I C, Chem Soc Rev, 43 (2014) 5326 [3] Maurer-Stroh et al., Nat Methods, 7 (2010) 237 [4] Jackson, M.; Mantsch, H. H., Crit Rev Biochem Mol Biol, 30 (1995) 95 [5] Klunk W E, Pettegrew J W and Abraham D J, J Histochem Cytochem, 37 (1989) 1273

Fig. 1. Amyloidogenic properties of three short peptide sequences, GNNQQNY, QVQIIE and ISFLIF, tested at physiological conditions of pH and temperature. (A) Far UV CD spectra of GNNQQNY and QVQIIE (dotted line: 0h of incubation; continuous line: 2 weeks of incubation). (B) FTIR spectra of ISFLIF in the amide I region (dotted line: 0h of incubation; continuous line: 2 weeks of incubation). (C) Congo Red binding assay of QVQIIE and ISFLIF. GNNQQNY shows spectra with no binding, similar to QVQIIE (data no shown) (dotted line: 0h of incubation; continuous line: 2 weeks of incubation). (D) AFM study of the three peptides morphology (center and right columns), displaying also positive and negative controls (left column). (E) Study of ISFLIF amyloid structure, imaged by AFM. (F) Height and width of ISFLIF amyloid fibrils, determined by AFM cross-sections (N = 120).

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r2= 76 mM-1

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Iron Oxide Nanoparticles as Contrast Agents for Magnetic Resonance Imaging Applications

Noelia Guldris1,3

, Bárbara Argibay2, Yury V. Kolen ko1, Enrique Carbó-Argibay1, Ramón Iglesias2, Francisco Campos2, Laura M. Salonen1, Manuel Bañobre-López1, José Castillo2, José Rivas1,3

1INL - International Iberian Nanotechnology Laboratory, Braga, Portugal

2Department of Neurology, Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain

3Department of Applied Physics, Technological Research Institute, Nanotechnology and Magnetism Lab NANOMAG, University of Santiago de Compostela, Spain

[email protected]

Magnetic Resonance Imaging (MRI) is a widespread technique used in the clinical field for the diagnosis of diverse diseases, such as stroke or cancer, since it allows the visualization of internal tissues and organs. In comparison with other imaging techniques, it displays some remarkable characteristics like high spatial resolution and noninvasiveness. However, a major drawback of this technique is its sensitivity: the natural contrast between healthy and damaged tissue is very low, which may complicate the diagnosis. Nowadays, contrast agents are used to increase the relaxation rates of surrounding water proton spins, which significantly enhances the clinical image resolution. The currently used contrast agents in clinics have mostly gadolinium as the magnetic ion, but its use has several drawbacks, such as toxicity and low lifetime in the blood stream. Therefore, the development of novel contrast agents based on e.g. iron oxide is of fundamental importance to avoid toxicity and improve lifetime and multifunctionality of the system. Here, we report on the parameters affecting the Superparamagnetic Iron Oxide Nanoparticle (SPION) relaxivity (Fig. 1). The parameters studied were the synthesis technique (hydrothermal and coprecipitation method), the polymeric coating (hydrophilic and hydrophobic polymers), and doping with magnetic and non-magnetic ions (Mn2+ and Zn2+). The in vitro validation was performed to probe the suitability of these SPIONs for biomedical applications. Hence, data of different SPIONs will be shown regarding magnetic and relaxivity properties, cytotoxicity, uptake behavior and MRI imaging capability.

Acknowledgement: this work is funded by POCTEP (Operational Programme for Cross-border Cooperation Spain-Portugal) and co-financed by the ERDF (European Regional Development Fund).

Figure 1: Parameters studied, which affect the relaxivity values.

Use of Nano-Technology and Nanomaterial in the Development of Nanocomposite Cementitious Materials; Review for Future Research Openings

Muhammad Ilyas Sheikh, Mizi Fan and Zhaohui Huang

School of Engineering and Design, Brunel University, Uxbridge, Middlesex, UB8 3PH, United Kingdom

[email protected]

Abstract

The main binder of concrete, Portland cement, represents almost 80% of the total CO2

emissions of concrete. This environmental impact can be reduced by limiting its production

and developing alternative cementitious composites. Strength of cementitious material is

also an essential requirement and cannot be trade-off by these alternative means.

Development in nanotechnology has led researchers to investigate the complex structure of

cement based materials at nano level to address both strength and environmental concerns.

In this review paper nanotechnology pathways, recently been paved in the field of nano-

composites for cementitious materials, are presented to understand how nano-science, nano-

engineering and nano-indendation is making a great impact in the development of

cementitious nanocomposite. Also generally used nanomaterial in the foregoing research to

enhance strength, durability and other multifunctional properties of cementitious materials

are highlighted. Among hundreds of nanomaterial available, only few of them are attracted

by the researchers due to their great influence on properties the cementitious materials.

Carbon nanomaterial such as carbon nanotubes (CNTs) and carbon nanofibers (CNFs)

generally used in the cementitious materials for enhancing the compressive and flexural

strength while nanoparticles of metal oxides such as TiO2, SiO2, Al2O3, Fe2O3 are reported

to improve the durability and multifunctional properties such as self-cleaning and self-

sensing ability. Moreover, studies on nano-clays, bio-nanomaterial and waste material

supplemented with nanomaterial properties are also presented to bridge the gap between

previous and future research for the development of environmental friendly high strength

cementitious nanocomposite with multifunctional properties.

References (Total 93 )

[01] efficacy of nano and microparticles in cementitious materials", Cement and Concrete Composites, vol. 36, no. 0, pp. 16-24.

[02] Sanchez, F. and Sobolev, K. (2010) "Nanotechnology in concrete A review", Construction and

Building Materials, vol. 24, no. 11, pp. 2060-2071.

[03] Pacheco-Torgal F, Miraldo S, Ding Y, Labrincha J. Targeting HPC with the help of nanoparticles. An overview. Constr Build Mater 2013;38:356 70.

[04] Davalos Jf. Advanace materials for civil infrastructure rehabilitation and protection. New York: Seminar at The Citty College of New York;2012.

[05] isley, Scotland, UK.

: :

:

[90] Shiho Kawashima, Pengkun Hou, David J. Corr, Surendra P. Shah, Modification of cement-based materials with nanoparticles, Cement and Concrete Composites, Volume 36, February 2013, Pages 8-15, ISSN 0958-9465, 10.1016/j.cemconcomp.2012.06.012.

[91] Alireza Naji Givia*, Suraya Abdul Rashidb, Farah Nora A. Azizc and Mohamad Amran Influence

of 15 and 80 nano-SiO2 particles addition on mechanical and physical properties of ternary

blended concrete incorporating rice husk ash, Journal of Experimental Nanoscience, 2013 Vol. 8, No. 1, 1 18,

[92] Hamed Younesi Kordkheili, Salim Hiziroglu, Mohammad Farsi, Some of the physical and mechanical properties of cement composites manufactured from carbon nanotubes and bagasse fiber, Materials & Design, Volume 33, January 2012, Pages 395-398, ISSN 0261-3069, 10.1016/j.matdes.2011.04.027.

[93] M. Aly, M.S.J. Hashmi, A.G. Olabi, M. Messeiry, A.I. Hussain, Effect of nano clay particles on mechanical, thermal and physical behaviours of waste-glass cement mortars, Materials Science and Engineering: A, Volume 528, Issue 27, 15 October 2011, Pages 7991-7998, ISSN 0921-5093, 10.1016/j.msea.2011.07.058.

Figures (Total 10)

Fig.1. Particle size and specific surface area related to concrete materials [03]

(Adopted and modified from the article of Sanchez and Sobolev. Constr Build Mat 24, 2060 2071).

Fig.5. Graphical representation of data showing the enhancement of compressive strength and flexural strength using carbon fibres and carbon nanotubes; Extracted from data [42]

CN

Nanocomposite

Engineered

Large-scale graphene film synthesized by plasma treatment of Cu foil and its electromagnetic shielding property

M. Ishihara

1, T. Yamada1, Y. Katou2, M. Ameya2, M. Horibe2, T. Nakamura3, H. Nanjo3, T. Ebina3, M. Hasegawa1

1 Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST),

Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, Japan 2 National Metrology of Japan (NMIJ), AIST, Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki, Japan

3 Research Center for Compact Chemical System, AIST, 4-2-1 Nigatake, Miyagino-ku, Sendai, Miyagi, Japan [email protected]

Abstract Conventional transparent electrodes make use of indium tin oxide (ITO) and are commonly used in touch screens, at panel displays and solar cells. Nearly 90% of ITO film market is for the touch screen application, which is expected to grow more and more in the future. Graphene is potential candidates for transparent conductive films for electrical and optoelectronic devices and various other applications due to its high electrical conductivity, chemical and physical stability. Graphene has been prepared by several methods, including precipitation on a silicon carbide surface, mechanical exfoliation from graphite, reduction of exfoliated graphene oxide, and growth by thermal chemical vapor deposition (CVD) on catalytic metal surfaces [1]. Bae et al, reported the synthesis of graphene by thermal CVD on a copper substrate at high deposition temperature of 1000 degree C and fabrication of transparent graphene electrodes [2]. We have synthesized high-quality graphene films by microwave plasma treatment of a copper substrate with Joule heating using low concentration carbon source [3]. The copper foil with A4 (211 mm X 297 mm) size was used as substrate. Few-layer graphene was deposited on the copper foil for a few minutes. The transfer of the graphene films to a desired target substrate is enabled by the wet-etching of the underlying copper foil. This is carried out by treating the film with an aqueous (NH4)2S2O8 solution after a support material is covered on the graphene/copper surface, in our case a surface protective sheet. The surface protective sheet is attached to the graphene/copper surface by using a film laminating roller with applying pressure. The result in a free-standing graphene/sheet film that can be handled easily and rinsed with deionized water to remove residual

etchant. The graphene/sheet film is placed on the 188- m thick polyethylene terephthalate (PET) substrate (graphene facing the surface). Finally, the surface protective sheet is removed from a sheet/graphene/PET film. We measured the transmittance and sheet resistance of the graphene/PET by using a haze meter and four probe method, respectively. The transmittance was 96% (except PET substrate) and the sheet resistance was about 500 ohm. The electromagnetic interference (EMI) shielding effectiveness (SE) of the graphene film was measured by using two waveguide-to-coaxial adapters and a vector network analyzer. The SE of the graphene film was more than several decibel. References [1] Xuesong Li, Weiwei Cai, Jinho An, Seyoung Kim, Junghyo Nah, Dongxing Yang, Richard Piner, Aruna Velamakanni, Inhwa Jung, Emanuel Tutuc, Sanjay K. Banerjee, Luigi Colombo, Rodney S. Ruoff, Science, 324 (2009) 1312. [2] Sukang Bae, Hyeongkeun Kim, Youngbin Lee, Xiangfan Xu, Jae-Sung Park, Yi Zheng, Jayakumar Balakrishnan, Tian Lei, Hye Ri Kim, Young Il Song, Young-Jin Kim, Kwang S. Kim, Barbaros O¨zyilmaz, Jong-Hyun Ahn, Byung Hee Hong, Sumio Iijima, Nature Nanotechnol., 5 (2011) 574. [3] Ryuichi Kato, Kazuo Tsugawa, Yuki Okigawa, Masatou Ishihara, Takatoshi Yamada, Masataka Hasegawa, Carbon, 77(2014)823.

Mechanical and electrochemical properties of niobium oxide layers deposited on Ti alloys by reactive magnetron sputtering process

M. Kalisz

1, M. Grobelny1, M. Mazur2, D. Wojcieszak2 & D. Kaczmarek2 1 Motor Transport Institute, Warsaw, Poland

2 Faculty of Microsystems Electronics and Photonics Wroclaw University of Technology, Wroclaw, Poland

[email protected]

Abstract Titanium and titanium alloys are widely used in a variety of engineering applications, where combination of mechanical and chemical properties is of crucial importance. Aerospace, chemical and automotive industries as well as medical device manufacturers also benefited from the outstanding properties of titanium alloys. Although, titanium alloys exhibit high strength and toughness, they are susceptible to chemical and electrochemical degradation. They may corrode and / or wear, leading to the degradation of material properties. In order to improve the mechanical and electrochemical properties of titanium alloys surface, surface modification is often required. Nb2O5 for several years is investigated as possible candidate for corrosion barrier coatings [1]. Properties of niobium oxide depend on deposition process and its parameters, such as reactant gas flow or pressure. It has been shown by Ramirez et al. [2] that hardness of thin niobium oxide films increased from 3.9 GPa to 5.3 GPa with increasing pressure and oxide content. On the other hand Chappe et al. [3] determined values hardness of niobium oxide films of about 6 GPa and Cetinorgu et al. [4] measured the hardness of amorphous Nb2O5 films deposited by dual ion beam sputtering as a function of the ion energy and the values ranged between 5.5 and 6.5 GPa The main objective of this research is to obtain new and innovative materials for titanium alloy (Ti6Al4V) corrosion protection, based on niobium oxide thin films deposited by reactive magnetron sputtering process. The structure, electrochemical corrosion and mechanical behavior of the alloy before and after niobium oxide thin films deposition were studied by SEM, potentiostat and nanohardness tester. The results show that the deposition of niobium oxide layers on the surface of the Ti6Al4V alloy, significantly improved corrosion resistance of titanium alloy in e.g. simulated body fluids and titanium alloy surface mechanical properties.

Innovative engine valves with improved performance, made of graphene- References [1] T. Ushikubo, Catalysis Today 57 (2000) 331-338, [2] G Ramirez, S.E. Rodil, S. Muhl, D. Turcio-Ortega, J.J. Olaya, M. Rivera, E. Camps, L. Escobar-Alarcón, Journal of Non-Crystalline Solids 356 (2010) 2714 2721, [3] J.M. Chappe, P. Carvalho, S. Lanceros-Mendez, M.I. Vasilevskiy, F. Vaz, A.V. Machado, M. Fenker, H. Kappl, N.M.G. Parreira, A. Cavaleiro, E. Alves, Surface & Coatings Technology 202 (2008) 2363, [4] E. Cetinorgu, B. Baloukas, O. Zabeida, J.E. Klemberg-Sapieha, L. Martinu, Applied Optics 48 (2009) 4536

Glycine and lysine assays with enzymatic reactions and examination of detection conditions

Akimitsu KUGIMIYA, Rie FUKADA, Shoko AMANO

Center for Industry and Public Relations, Hiroshima City University, 3-8-24 Senda-machi, Naka-ku, Hiroshima 730-0052, JAPAN

[email protected]

Abstract Glycine is the amino acid which constitutes collagen and it has a role which maintains elasticity with glowing skin. It also exists in the backbone or the brain stem mostly, and works as neurotransmitter of a control system of the central nerves. In contrast, lysine tends to occur at the lowest levels in the human body; further decreases in lysine concentration cause failures in liver function that lead to increased serum saturated fat and cholesterol levels [1]. Analyses of free amino acids in biological fluids may therefore be useful in determining disease status in clinical diagnoses [2-3].

For the analysis of each amino acid concentration, such as high-performance liquid chromatography (HPLC) has been used generally; however, the conventional analytical methods are burdensome in terms of cost, time, and space requirements. HPLC methods for amino acids, for example, take several hours to complete. The development of simple and rapid analytical tools for measuring amino acid concentrations is desirable for the clinical diagnostics and food industries.

We have studied a novel approach for the detection of each amino acid that involved the use of aminoacyl-tRNA synthetase (aaRS) as a molecular recognition element [4-7], because aaRS mediates biosynthesis of proteins and peptides in the body, thus it is expected to a selective binding ability for corresponding amino acid.

In this study, in order to obtain a simple amino acid detection system, for the specific detection of glycine and lysine, glycyl-tRNA synthetase and lysyl-tRNA synthetase were used as the each amino acid recognition element respectively, and these were coupled to the measurement of hydrogen peroxide via several enzymatic reactions, and the results were spectrophotometric method and absorbance was measured at 556 nm.

The consecutive enzymatic reactions used in this study are as follows: SerRS binds to its cognate amino acid, serine, and releases inorganic pyrophosphate (Scheme, Equation [1]). Hydrogen peroxide (H2O2 (TOOS) was injected into the reaction mixture (Equation [4]). The absorbance change at 556 nm was measured using a microplate reader, and the selective and quantitative responses of the biosensor were evaluated. This approach provided selective quantitation of up to 25 M glycine and also showed selective response to glycine in 100 mM Tris-HCl buffer (pH 8.0) selectively (Figure 1).

This work was partly supported by JSPS KAKENHI Grant Number 25330344.

References

[1] A. Sánchez, D.A. Rubano, G.W. Shavlik, R. Hubbard, M.C. Horning, Arch Latinoam Nutr., 38, (1988) 229-238.

[2] Y. Noguchi, Q.W. Zhang, T. Sugimoto, Y. Furuhata, R. Sakai, M. Mori, M. Takahashi, T. Kimura, T., Am. J. Clin. Nutr., 83, (2006) 513S-519S.

[3] Y. Miyagi, et al., PLoS ONE, 6, (2011) 1-12. [4] A. Kugimiya, M. Morii, T. Ohtsuki, Anal. Biochem., 378, (2008) 90-92. [5] A. Kugimiya, E. Takamitsu, Mater. Sci. Eng. C, 33, (2013) 4867-4870. [6] A. Kugimiya, R. Fukada, D. Funamoto, Anal. Biochem., 443, (2013) 22-26. [7] A. Kugimiya, E. Matsuzaki, Appl. Biochem. Biotech., (2014) accepted.

Figures

Scheme 1 Enzymatic reaction equations

Figure 1 Selectivity test for 20 natural amino acids during Glycine sensing. Twenty natural amino acids, each at a concentration of 50 M, were added to the reaction mixture, and the absorbance at 556 nm was measured using a microplate reader. Data represent the average of 3 measurements, and the standard deviation is indicated by error bars.

Transmission of signals using white and visible LEDs for VLC applications

P. Louro1,2, V. Silva1,2, I. Rodrigues1, M. A. Vieira1,2, M. Vieira1,2,3 1Electronics Telecommunication and Computer Dept. ISEL, R. Conselheiro Emídio Navarro, 1959-007

Lisboa, Portugal 2 CTS-UNINOVA, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal. 3 DEE-FCT-UNL, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal

[email protected]

Abstract

Recent developments in LEDs allowed them to be used in environmental lighting and have revealed many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Besides this general lighting application, LEDs are now used in other specific fields such as automotive headlamps, traffic signals, advertising, and camera flashes. However another emerging field of application is in advanced communications technology due to its high switching rates. Thus, the visible light spectrum is currently being used in the Visible Light Communication (VLC) technology, taking advantage of the lighting infrastructure based on white LEDs. These energy-saving white light sources devices were enabled by the invention of efficient blue LEDs. In this paper we propose the use of a multilayered pinpin device based on a-SiC:H to work as a photodetector operating in the pertinent range of operation for VLC (375 nm 780 nm) using as optical sources white and visible wavelength LEDs [1]. The device consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructure with low conductivity doped layers, sandwiched between two transparent contacts (Figure 1). It works as an optical filter in the visible range with tunable spectral sensitivity dependent on both applied bias and type of steady state optical bias (wavelength, intensity and direction of incidence on the device). Optoelectronic characterization of the device is presented and includes with spectral characterization of the optical sources (figure 2), spectral response, transmittance and I-V characteristics, with and without background illumination of the photoddetector (Figure 3). Results show that when the device is biased with front optical steady state light of short visible wavelength (400 nm) superimposed with the pulsed light emitted from the optical transmission sources, it exhibits an increased output current in the long part of the spectrum (550-650 nm), and a reduction of the same photocurrent for the short wavelengths (400-500 nm). An opposite behavior is observed when the wavelength of the background is changed to longer values. A comparison of the performance of white LEDs and visible wavelengths is presented. Results show that, front background enhances the light-to-dark sensitivity of the medium, long and infrared wavelength channels and quench strongly the low wavelength, depending optical amplification on the background intensity. The change of the impinging side of the steady state illumination produces the reverse effect, as the output photocurrent is enhanced under short wavelength signals and range and strongly reduced it under the long wavelength (figure 4). A decoding algorithm for the detection of different optical signals is presented and discussed with a self-recovery error procedure. A capacitive optoelectronic model supports the experimental results (figure 5) and explains the device operation. A numerical simulation will be presented.

References [1] - , P. Louro, V. Silva, I. Rodrigues M. A. Vieira, M. Vieira, Mater. Res. Soc. Symp. Proc. Vol. 1693 © 2014 Materials Research Society, DOI: http://dx.doi.org/10.1557/opl.2014.569 [2] - , P. Louro, V. Silva, M. A. Vieira, M. Vieira, physica status solidi (c), Special Issue: E-MRS 2014 Spring Meeting Symposium X, Volume 11, Issue 11-12, pages 1703 1706, November 2014, DOI: 10.1002/pssc.201400035

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Fig.2 Emission spectrum of the warm white LEDs: a) phosphor based; b) tri-chromatic based.

Fig.1 Simplified schematic diagram of the device

structure.

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conditions and using front and back violet light.

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back optical bias.

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combined signal with front and back optical bias (C1=0.8 nF, R1 2 (front)=0.2 nF, C2 (back)=0.15 nF R2

Surface morphology and corrosion investigation of AZ91RC magnesium alloy

B. Mingoa, R. Arrabal

a, M. Mohedano

b, A. Pardo

a, E. Matykina

a, M.C Merino

a

aDepartamento de Ciencia de Materiales, Facultad de Ciencias Químicas, Universidad

Complutense, 28040, Madrid, Spain

bHelmholtzZentrumGeesthacht, Magnesium Innovation Centre, Institute of Materials Research,

Max-Planck-Str. 1, D-21502 Geesthacht, Germany.

E-mail: [email protected]

ABSTRACT

Rheocast processing of AZ91 magnesium alloy was evaluated in terms of microstructure and

corrosion resistance. Rheocasting leads to a globular microstructure of -Mg spheres separated

by an interconnected -Mg17Al12 ( -phase) network. Findings revealed that early stages of

corrosion were located at the center of -Mg globules and more importantly at -Mg/ -phase

interfaces due to galvanic coupling as predicted from surface potential maps. Electrochemical,

hydrogen evolution and weight loss measurements demonstrated the superior corrosion

resistance of the rheocast alloy. This was attributed to an improved barrier effect of the -

Mg17Al12 phase related to its morphology, quantity and composition. For long immersion times,

only small attacked areas were observed which corresponded to randomly corroded -Mg

globules. High resolution 3D measurements of the corroded areas after removal of the corrosion

products were obtained in order to further evaluate the corrosion morphology.

Magnetic and morphologic properties of Alnico-based rare-earth free permanent magnets

Farzin Mohseni, M. J. Pereira, N. M. Fortunato, J. S. Amaral, A. C. Lourenço, J. M. Vieira

Department of Physics, University of Aveiro, 3810-193, Aveiro, Portugal [email protected]

Abstract

Due to recent dramatic increases in the price of rare-earth elements, rare-earth free permanent magnet research is nowadays a very active field [1]. are hard ferromagnets, with high working temperatures, albeit with modest coercivity, below 1 kOe [2]. This makes their energy product (~12 MGOe) compare unfavorably with rare-earth based NdFeB magnets (~55 MGOe). Recently, an unusually high coercivity value, up to ~ 10 kOe, was reported for DC-sputtered Alnico V thin-films on Silicon substrates [3, 4], due to the formation of a novel Body Centered Tetragonal Fe-Co-Si phase, a result of diffusion of Si ions from substrate to thin film. This diffusion mechanism is still unclear, and the chemical composition and saturation magnetization of this novel phase are not yet characterized.

We report on the effects of deposition temperature and post heat treatments on the morphology and magnetic properties of Alnico V thin films prepared by RF-sputtering. The sputtering target was of commercial Alnico V alloy, and substrates were of 700 µm thick Si(100). Samples of 180 nm thickness were prepared at different deposition temperatures, ranging from room temperature to 560 C. Post-

deposition heat treatments in vacuum at 600, 800 and 900 C, followed by quenching in liquid Nitrogen and slow-cooling, were performed.

Atomic Force Microscopy (AFM) shows that both an increase of deposition temperature as well as post heat treatments lead to a considerable increase of roughness, from < 0.8 nm to 80 nm, for heat treatments at 600 C, and 50 nm for a deposition temperature of 500 C (Figure 1).

The chemical composition of the thin films was analyzed by Electron Dispersion Spectroscopy (EDS) in a Scanning Electron Microscope (SEM). The composition of films deposited at room temperature, matches that of the target, while for higher substrate temperatures the ratio between transition metals is altered, and post-deposition heat treatments introduce contaminations to the thin films. Figure 2 shows the cross-section SEM image of the as-made and heat treated films.

Magnetization analysis using a Vibrating Sample Magnetometer (VSM) shows that substrate temperature affects the saturation magnetization, lowering it drastically for high temperatures. In the case of heat treatments this decrease is smoother, but still quite substantial, particularly for quenched samples. Coercivity is unaffected by deposition temperatures in this range, while increasing considerably (from < 20 Oe for as-deposited films up to 480 Oe) in heat-treated samples (Figure 3).

Future studies will focus on film thickness and substrate temperature optimization, and the control of surface roughness under heat-treatments, by adding a capping layer to the films (Ag, Ta), preventing also the observed oxidation of the surface during heat treatment and quenching.

We acknowledge funding from FEDER/COMPETE through FCT, FCOMP-01-0124-FEDER-037271 (PEst-C/CTM/LA0011/2013) and EXPL/CTM-NAN/1614/2013 - FCOMP-01-0124-FEDER-041688. References

[1] Narayan Poudyal and J Ping Liu, Journal of Physics D: Applied Physics 46 (2013) 043001 (23pp). [2] K. H. J. Buschow, Reports on Progress in Physics 54 (1991) 1123-1213. [3] O. Akdogan, G. C. Hadjipanayis, Journal of Physics: Conference Series 200 (2010) 072001.

[4] O. Akdogan, W. Li, G. Hadjipanayis, Journal of Nanoparticle Research (2012) 14 891.

Figures

Figure 1 AFM image of a) as-deposited C.

Figure 2 Cross sectional SEM image of a) as-deposited, b) after heat treatment

Figure 3 Effects of a) heat treatment followed by slow cooling, b) heat treatment followed by quenching

and c) deposition temperature on hysteresis loop

Effect of biodegradation on PLA/graphene-nanoplatelets composites mechanical properties and biocompatibility

Artur M. Pinto1,2, Carolina Gonçalves1, Inês C. Gonçalves2, Fernão D. Magalhães1 1LEPABE, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal

2INEB, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal [email protected]

Abstract

Two types of graphene-nanoplatelets (GNP-M and GNP-C) were incorporated in PLA (poly(lactic acid)) by melt blending. Materials were biodegraded during 6 months and characterized by XRD, tensile tests, DMA and biocompatibility assays. For both fillers, low loadings (0.25 wt.%) improved mechanical properties and decreased their decay until 6 months biodegradation. PLA degradation decreased its toughness (AUC) by 10 fold, while for PLA/GNP-M and C after 6 months degradation, toughness was only reduced by 3.3 and 1.7 fold, respectively. Comparing with PLA, PLA/GNP-M and C composites presented similar (HFF-1) fibroblasts adhesion and proliferation at the surface and did not released toxic products (6 months).

Introduction

Graphene is a single layer of sp2 carbon atoms arranged in a honeycomb structure and possesses extraordinary mechanical strength and an extremely high surface area. [1] A commercial available product, with reduced cost comparing with single layer graphene, graphene nanoplatelets (GNPs), are constituted by few stacked graphene layers, possessing oxygen containing functional groups in the edges. GNPs present high aspect ratio, thus forming a percolated network in composites, with large interfacial interaction between platelets and polymer matrix, mainly in the edges, resulting in effective load transfer and increased strength. [2] Moreover, these materials were shown to be non-toxic when incorporated in low percentages into PLA. [3] The potential of GNPs as polymers fillers, has been observed in our previous study, in which improvements in mechanical properties of PLA thin films were obtained at filler loadings bellow 1 wt.%. Solvent mixing was used for GNPs incorporation, [4] however the use of solvents should be avoided due to the toxicity of residues that may remain in the materials, and for industrial workers [5]. Lahiri et al. improved ultrahigh molecular weight polyethylene mechanical properties producing composites by electrostatic deposition of GNPs 1 wt.%. However, composites were toxic to osteoblasts because filler leaching occurred. [2] Thus, melt blending, which assures complete embedding of GNPs in polymer matrix preventing filler leaching, is studied in this work as a green method for production of PLA/GNPs composites.

Materials and Methods

PLA 2003D, was purchased from Natureworks. Graphene-nanoplatelets, grade C750 (GNP-C) and M-5 (GNP-M) were acquired from XG Sciences. PLA/GNP-M and C 0.25 wt.% composites were prepared by melt blending in a Thermo Haake Polylab (180 °C, 15 min, 25 rpm), and moulded in a hot press (190 ºC, 2 minutes) into thin sheets (0.3-0.5 mm). Samples were immersed in 50 mL PBS in sterile conditions and incubated for 6 months (37 °C, 100 rpm). X-Ray diffraction (XRD) analysis, was performed using a Philips X´Pert diffractometer. Tensile properties of the composites (60x15 mm) were measured (Mecmesin Multitest-1d, Mecmesin BF 1000N) at room temperature and strain rate of 10 mm min-1. Dynamical mechanical analysis (DMA) was performed using a DMA 242 E Artemis (Netzsch) in tension assays (6N, 10 minutes) with 10 minutes recovery. Biocompatibility of materials was evaluated using HFF-1 cells cultured at the surface of PLA, PLA/GNP-M and C 0.25 wt.% films (Ø = 5.5 mm) and in direct contact with materials extracts obtained after 6 months incubation in PBS (50 µL in 150 µL DMEM+, after 24h cell grow). In both assays cells were seeded in 96 well plates (7500 cells per well) and 20 µL resazurin solution added at 24, 48, and 72h and incubated for 3h, fluorescence

ex/em=530/590 nm) read and metabolic activity evaluated (Metabolic activity (%) = Fsample/FPLA x 100). Suitable controls were performed for both biocompatibility assays.

Results and discussion

XRD

GNP-M and C powders present similar XRD spectra, typical of carbon materials, with an intense peak around 31°, and two broad peaks around 50° and 65°. PLA, before (0M) and after 6 months (6M) biodegradation, presents similar spectra with two broad peaks, the first, around 20°, is more intense than the second, around 35°. PLA/GNP-M 0.25 wt.% 0 and 6M present similar spectra, with PLA and GNP-M peaks being observed, which confirms the filler presence in polymer matrix. For PLA/GNP-C 0.25 wt.% 0M and 6M spectra are also similar, however GNP-C peak is less intense than GNP-M peak.

Tensile tests

Incorporation of GNP-C and M in PLA increased its Young´s modulus by 14 %. Also, tensile strength is increased by 20% with GNP-C incorporation and by 6% with GNP-M. Improvements in toughness of 20% are only observed for GNP-C. After 6 months biodegradation no significant changes are observed in Young´s modulus for all materials tested. Decreases in tensile strength, elongation at break, and toughness are respectively, for PLA of 2.6, 2.5, and 10 fold, for GNP/PLA-M of 1.6, 1.8 and 3.3 fold, and for GNP-C of 1.4, 1.4 and 1.7 fold. Thus, the presence of the fillers prevents decreases of PLA mechanical properties with biodegradation, namely tensile strength, elongation at break and toughness. Also, GNP-C incorporation seems to have a more beneficial effect than GNP-M, especially in toughness.

DMA

Figure 1 shows that for PLA, dLf (final, at 6N) after 10 cycles before degradation was of 14.2 µm, being of 13.7 and 13.2 µm for PLA/GNP-M and C 0.25 wt.%, respectively. After 6 months degradation, PLA sample ruptured after 4 cycles (1.A) reaching a dLf of 56.3 µm, PLA/GNP-M and C 0.25 wt.% did not ruptured (1.B,C) and presented a slight increase in dLf, which were of 16.8 and 16.7 µm, respectively.

These results are in agreement with those obtained in tensile tests, with a significant decay in PLA mechanical properties after 6 months biodegradation and small effects observed for PLA/GNP-M and C 0.25 wt.%. Thus, fillers are reinforcing the polymer matrix and retarding decrease of its mechanical properties. Materials degradation was confirmed by GPC-SEC and SEM (results not shown).

Cell adhesion and proliferation assays

HFF-1 cell metabolic activity at PLA surface was 75% at 24 and 48h, and 94% at 72h, comparing with cells at tissue culture treated surface of 96 well plates. PLA/GNP-M and C 0.25 wt.%, metabolic activity never decreased below 90%, for both composites in comparison with PLA. Thus, fillers incorporation has no impact in cell adhesion and proliferation at materials surface.

Degradation products cytotoxicity

A control performed with PBS (37 ºC, 100 rpm, 6 months) presented similar cell metabolic activity (24, 48, 72h) to PLA 6M degradation products, which shows that they are not toxic. Figure 2 shows that degradation products of PLA/GNP-M and C 0.25 wt.% 6M are not toxic (24, 48, 72h), comparing with PLA 6M, according to ISO 10993-5:2009(E), which considers toxic a material that decreases cell viability below 70% of negative control for cell viability. Also, cell morphology is normal and similar for all conditions tested (images not shown).

Conclusions

GNP-M and GNP-C incorporation in PLA matrix at low loadings (0.25 wt.%) improved mechanical properties and decreased their decay until 6 months biodegradation. These nano-fillers can be used to tune PLA mechanical performance during biodegradation. PLA/GNP-M and C composites allow similar HFF-1 cell adhesion and proliferation at the surface and do not release toxic products.

References

[1] Kim K, Abdala A and Macosko W, Macromolecules, 43 (2010) 6515. [2] Lahiri D, Rupak D, Cheng Z, Socarraz-Novoa I, Bhat A, Ramaswamy S, Agarwal A, ACS Appl. Mater. Interfaces, 4 (2012) 2234. [3] Pinto AM, Moreira S, Gonçalves IC, Gama FM, Mendes AM, Magalhães FD., 2013. Biocompatibility of poly(lactic acid) with incorporated graphene-based materials, Colloids Surf B Biointerfaces, 104 (2013) 229. [4] Pinto AM, Cabral J, Tanaka DA, Mendes AM, Magalhães FD, Effect of incorporation of graphene oxide and graphene nanoplatelets on mechanical and gas permeability properties of poly(lactic acid) films, Polymer International, 62 (2013) 33. [5] Pinto AM, Gonçalves IC, Magalhães FD, Colloids and Surf B Biointerfaces, 111 (2013) 188.

The influence of surface preparation on the corrosion and mechanical properties of Ti6Al4V titanium alloy

Marcin Ornowski1, Marcin Grobelny1, 1

1Motor Transport Institute, Jagiellonska 80, 03-301 Warsaw, Poland

[email protected]

The physical, chemical and mechanical properties of titanium alloys make this materials an

appropriate candidate for a variety of technical applications. The highest strength to weight ratio of all

metals up to 600°C and an excellent resistance against wet corrosion due to spontaneous formation of

a passivating oxide layer have introduced titanium components into the fields of chemical, aerospace

and biomedicine engineering. The oxides layers are barrier between the surrounding environment and

the underlying metallic titanium. Nevertheless, in all materials the passive layer can be mechanically

damaged and also in the presence of aggressive anion species, especially fluoride ions F-, oxides layer

is not sustainable. This leads to a significant reduction in corrosion resistance of titanium alloy.

Various surface modification technologies have been proposed and investigated with a view to

improving the corrosion and mechanical properties of titanium alloys, including anodizing, laser alloying,

coating techniques, heat treating processes and ion implantation processes. However, the continued

search for new methods of surface modification of titanium alloys to improve their mechanical

parameters and corrosion resistance is under way. These methods include also plasma technologies

i.e.: the plasma enhanced chemical vapour deposition process (PECVD) and magnetron sputtering

process preparation of thin dielectric layers are growing in popularity. However, before any process of

coatings manufacturing, it is appropriate to surface preparation of metal alloy.

The paper focuses on the comparative studies of corrosion and mechanical properties of

Ti6Al4V titanium alloy after surface preparation by different methods: mechanical polishing and

electrochemical polishing, and influence on the corrosion properties of nanocoatings.

The tests were done by means of voltametric measurements in a fluoride solution. Surfaces of

the titanium alloy was characterized using atomic force microscope, nanoindentation measurements

and scanning electron microscope.

GRAF-

TECH/NCBR/14/26/2013) in the framework of the National Centre for Research and Development,

Graf-Tech Programme.

Adsorption equilibrium, kinetics and thermodynamics of CdTe quantum dots with distinct cappings using different solid supports

S. Sofia M. Rodrigues, Christian Frigerio, João L. M. Santos, M. Lúcia M. F. S. Saraiva,

Marieta L. C. Passos

REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal

[email protected]

Abstract Semiconductor nanocrystals, or quantum dots (QDs) have been used, during the last decade, as bioimaging tools with great potential to definite chemosensors with different applications [1]. In order to improve the applicability of these nanomaterials in chemosensors, the immobilization of quantum dots onto solid supports has been used [2]. The immobilization enables multiple or repetitive uses and when compared with the consecutive utilization of successive batches, it allows a more sustainable and rational utilization. In addition, the immobilization assures a more cost-effective operation, minimization of reagent consumption and waste production. It also allows stable measurements and consequently reproducible analytical signals. In this work we have evaluated distinct strategies to carry out the immobilization of QDs onto solid supports (Figure 1). It was studied solid supports with distinct characteristics and it was evaluated the influence of QDs capping and size, concentration, pH, temperature, contact time between the solid and the QDs (Figure 2), etc. Adsorption equilibrium was established and the maximum adsorption of QD on the solid support was evaluated. In order to analyze the equilibrium data, Freundlich and Langmuir isotherms were used and kinetic data were fitted to the pseudo-first-order and pseudo-second-order models. It was also calculated different thermodynamic parameters as Gibbs free energy, enthalpy and entropy and the stability of immobilized QDs was confirmed. References [1] C. Frigerio, D.S.M. Ribeiro, S.S.M. Rodrigues, V.L.R.G. Abreu, J.A.C. Barbosa, J.A.V. Prior, K.L. Marques, J.L.M. Santos, Analytica Chimica Acta, 735 (2012) 9. [2] C. Frigerio, J. L. M. Santos, J. A. C. Barbosa, P. Eaton, M. L. M. F. S. Saraiva, M. L. C. Passos, Chem. Commun., 49 (2013) 2518. Acknowledgments This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project Pest-C/EQB/LA0006/2013. The work also received financial support from the European Union (FEDER funds) under the framework of QREN through Project NORTE-07-0124-FEDER-000067. Marieta L. C. Passos thanks FCT, Pos-doc grant (SFRH/BPD/72378/2010). S. Sofia M. Rodrigues thanks FCT and FSE for the Ph.D. Grant (SFRH/BD/70444/2010).

Figures

Figure 1: Fluorescence microscopy images of adsorbed GSH QDs (A) and MPA QDs (B) on CPG and CB solid supports, respectively.

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Gd3+ Functionalized Iron-Filled Multi-Walled Carbon Nanotubes for MRI Imaging and Magnetic

Hyperthermia Cancer Therapy

Taze Peci

University of London, UK

A simple wet chemical method involving only sonication in aqueous GdCl3 solution was used for surface functionalization of iron-filled multi-walled carbon nanotubes with gadolinium. The soni-cation process led to the formation of functional groups on the sidewalls which provide active nucleation sites for the loading of Gd3+ ions, the desirable oxidation state for MRI contrast agent functionality. Characterization by EPR, EELS, and HRTEM confirmed the presence of Gd3+ ions on the sidewall surface and defect sites. The room temperature ferromagnetic properties of the encapsulated iron nanowire, saturation magnetization of 40 emu/g and coercivity 600 Oe, were maintained after surface functionalization. Heating functionality in an r.f. applied magnetic field was quantified through the measurement of specific absorption rate: 50 W/gFe at magnetic field strength 8 kA/m and frequency of 696 kHz. These results demonstrate the viability as dual-functioning MRI imaging and magnetic hyperthermia structures for cancer therapy.

Scanning Thermal Microscopy: unraveling and mapping thermal phenomena at the nanoscale

M. J. Pereira1, J. S. Amaral1, N. J. O. Silva1, V. S. Amaral1

1 Departamento de Física and CICECO, Campus de Santiago, Universidade de Aveiro, 3810-193

Aveiro, Portugal [email protected]

Abstract

There has been growing interest in obtaining greater knowledge on heat transport phenomena in nanostructured materials, since they are often determinant for the performance of modern micro and nano-devices, such as sensors possessing nano-sized features and thermoelectric nanomaterials. Furthermore, nanoscale thermal properties assume great relevance in modern electronic circuits that dissipate power at the nanoscale.[1] Scanning thermal microscopy (SThM) is a powerful tool with a leading role concerning probing and mapping of local thermal properties of materials and heat generation with nanometric spatial resolution. Based on an atomic force microscope (AFM), the SThM uses a specialized heated thermal probe designed to act as a thermometer instead of the conventional AFM tip. Since its invention, AFM revealed itself a fundamental mean for imaging and introducing features at the nanoscale that alter the structure and properties of the materials. Enabling self-heating on a conventional AFM tip paved the way for its implementation, in the form of Scanning Thermal Microscopy, not only in a wide variety of manufacturing and imaging applications with unmatched quality, but also as a leading technique in the search for thermal functional properties. Determining and acting on the thermo-physical properties of microstructures is thus of great use in understanding/modelling heat transfer and macroscopic properties of heterogeneous materials. As an example, the study of contrast thermal properties is especially important for the study of polymer composites and lithographed materials.

The fundamental feature of this technique, the SThM tip, is a nanofabricated thermal probe that can act as a resistance thermometer or a resistive heater, depending on the selected operation mode: passive mode or active mode, also known as temperature contrast mode (TCM) and (thermal) conductivity contrast mode (CCM), respectively. It is also possible to collect simultaneously surface topography image and thermal image of the samples under analysis due to the independent nature of both AFM and SThM mechanisms in the same equipment (fig. 1).

Here we present exploration routes for the study of phenomena by Scanning Thermal Microscopy. Using a XE7 Scanning Probe Microscope with Scanning Thermal Microscopy from Park Systems [2], in this presentation we show the path for research in relevant topics, namely thermal conductivity of graphene layers deposited on different substrates by conductivity contrast, the electrocaloric or magnetocaloric effects in nanostructured materials. Further work on inducing and studying structural phase transformations on thin films of functional materials with relevant properties for application in nano-devices, such as BaTiO3 and Ni2MnGa is also presented. Work in progress for this technique includes also its application to time dependent processes, bringing it forward as a contribution to otherwise complex analysis of dynamic processes.

Due to its high thermal conductivity and subsequent efficiency in heat conduction, graphene is noted as suitable candidate to aid overcome the obstacle of increasing dissipation power density arising

combined with highly interesting electronic and optical properties, recommend it for a wide range of applications in several fields. [3.lack clarity. It has been shown that graphene monolayers possess high thermal conductivity, but the values obtained so far seem to vary according to the deposition method and measurement technique. SThM presents itself as a reliable technique to clarify the intriguing thermal properties of graphene monolayers (fig. 2), namely by enabling accurate estimation of the thermal conductivity of this material supported by different substrates, relying on thermal contrast between the graphene monolayer and other materials with known thermal conductivity [4].

The electrocaloric (EC) effect consists in the variation of temperature that some materials experience under an applied electric field, which is enhanced at temperatures near ferroelectric phase transitions. [5] This is why EC is becoming an interesting alternative to refrigeration based on the magnetocaloric effect due to the economically inviable large magnetic fields that this effect requires. [6 ][7] Thin films exhibit especially high EC effects. However, direct measuring of EC in thin films is hard to accomplish due to the great difference between heat flow output shown by thin film and substrate. SThM solves this inconvenience, allowing direct measurement mapping of temperature changes in several spots of a thin film, enabling and promoting thus the search for promising materials for micro-scale cooling applications.

References

[1] Microscale and Nanoscale Heat Transfer, Berlin Springer (2007) 181-236 [2] http://www.parkafm.com [3] Alexander A. Balandin, Suchismita Ghosh, Wenzhong Bao, Irene Calizo, Desalegne Teweldebrhan, Feng Miao, Chun Ning Lau, Nano Lett., 8 (2008) 902 907 [4] Anton N. Sidorov, Daniel K. Benjamin, Christopher Foy, Appl. Phys. Lett., 103 (2013) 243103 [5] S. Kar-Narayan, S. Crossley, X. Moya, V. Kovacova, J. Abergel, A. Bontempi, N. Baier, E. Defay, N. D. Mathur, Appl. Phys. Lett., 102 (2013) 032903 [6] Dongzhi Guo, Jinsheng Gao, Ying-Ju Yu, Suresh Santhanam, Gary K. Fedder, Alan J. H. McGaughey, S. C. Yao, Appl. Phys. Lett., 105 (2014) 031906 [7] Xavier Moya, Enric Stern-Taulats, Sam Crossley, David González-Alonso, Sohini Kar-Narayan, Antoni Planes, Lluís Mañosa, Neil D. Mathur, Advanced Materials, 25 (2013) 1360 1365

- COMPETE and by national funds through FCT - Fundação para a Ciência e Tecnologia with the projects HEAT@UA RECI/CTM-CER/0336/2012 and PEst-C/CTM/LA0011/2013 (FCOMP-01-0124-FEDER-037271)

Figures

Fig. 1 Schematic showing the independent nature of both mechanisms for topographical and thermal

images collection (adapted from Park Systems [2])

Fig. 2 Left: topographical image of Si/graphene interfaces performed with thermal nanoprobe of SThM system; Right: SThM conductivity contrast image (CCM) of the area depicted on the left and line profile showing the contrast in thermal conductivity between graphene and Si

The assembly of the nanoparticle-based assays with automatic flow sytems: potentialities and limitations

André R.T.S. Araujoa,b, Marieta L. C. Passosa, Paula C. A. G. Pintoa, M. Lúcia M. F. S. Saraivaa

a REQUIMTE, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira nº 228, 4050-313 Porto, Portugal

b Unidade de Investigação para o Desenvolvimento do Interior - Instituto Politécnico da Guarda (UDI-IPG), Av. Dr. Francisco Sá Carneiro nº 50, 6300-559 Guarda, Portugal

[email protected]

Abstract

Nanotechnology constitutes an appealing and pursued research area which has already demonstrated its potential in numerous and varied applications. A core piece of this technology is the use of nanomaterials ranging from industrial, chemical, medical, to environmental fields. Among the nanomaterials, nanoparticles (NPs) have a number of key properties that make them particularly attractive in different formats, such as when used as quantitation tags, acting as analytical signal catalysts, in the analyte recognition and scavenging/separation, or when functionalized to carry out specific functions, especially in the biomedical field.

The idea of assembling the NPs with flow management approaches seems to be advantageous since it permits confined, precise, rigorous and reliable analysis within a shorter timeframe, besides allowing to take advantage of the particular features of the NPs, such as their unique electrical, optical and magnetic properties, high adsorption capacity and target compounds binding ability. In fact, these approaches enable a precise control of the reaction environment and of the constituent reaction steps, being adequate for the implementation of complex reactional schemes or multiparametric determinations, and guarantee that the consumption of expensive or toxic reactants is minimized and the subsequent waste generation.

This communication is intended to review the state-of-the-art of flowing stream systems comprising NPs as analytical tools, with different chemical nature, like noble metals (gold and silver), magnetic materials, carbon, silica or quantum dots. Particular emphasis will be dedicated to the categorization of the NPs-based assays in the different flow strategies, namely flow injection analysis (FIA) [1] and sequential injection analysis (SIA) [2], where the most representative applications will be selected and the main achievements and limitations will be discussed. Furthermore, it will be envisaged possible future trends of the analytical potential of NPs focusing on their use in automated flow-based approaches.

The ease of implementation of these NPs-based assays in the flow systems, by the use of readily-available equipment, less expensive instruments and by coupling usual detection systems found in most laboratories, and the rigorous and exquisite control of the reaction environment conditions attained in these closed systems open clearly new avenues to expand the knowledge about the NPs synthesis and reactivity and thereby to fully exploit the tremendous analytical potential of nanoparticles in conventional and novel application fields.

[1] J. Ruzicka, H. Hansen, Analytica Chimica Acta, 78 (1975) 145–157.

[2] J. Ruzicka, G.D. Marshall, Analytica Chimica Acta, 237 (1990) 329–343.

Preparation and characterization of antidot complement of square artificial spin ice

I.R.B. Ribeiro,1,2 R.C. Silva,3 S.O. Ferreira,1 W.A. Moura-Melo,1 A.R. Pereira1 and C.I.L. de Araujo1

1Universidade Federal de Viçosa, Dept. of Physics, 36570-900, Minas Gerais, Viçosa, Brazil 2 Instituto Federal de Educação, Ciência e Tecnologia do Espírito Santo, Campus de Alegre, 29500-

000, Espírito Santo, Alegre, Brazil 3 Universidade Federal do Espírito Santo, Dept. of Physics, 29932-540, Espírito Santo, São Mateus,

Brazil

[email protected]

Abstract Nanomagnetism has been intensively investigated due its unusual properties and promise for

possible applications ranging broadly from information storage using topological objects (vortices and skyrmions) [1-2] as well as many biological and medical applications such as magnetic separation, hyperthermia treatment, magnetic resonance contrast enhancement and drug delivery [3]. Recently, significant interest has emerged in fabricated systems that mimic the behavior of geometrically frustrated materials. Wang et al. [4] have fabricated artificial spin ice (ASI): elongated single-domain ferromagnetic nanoislands organized in regular square lattice.

Based in this geometry we fabricated a lattice of elongated holes (antidots), with the aspect ratio of 2:1 (length: width), arranged in a nickel film mimicking the geometry of the ASI system, referred to as antidot-ASI [5]. To prepare these structures on silicon (100) substrate, first was deposited a polymethyl methacrylate (PMMA) layer of 250 nm by spin coating. Then, the silicon with PMMA was dried in hotplate. Subsequently, the desired pattern was defined by e-beam lithography. After e-beam exposure and developing, the structures were transferred into the Thermionics E-Beam evaporation system where a homogeneous 25 nm nickel film was evaporated over an 8 nm titanium seed layer. The nickel was capped with 3 nm of Au to prevent oxidation of the magnetic material. The procedure was completed by lift-off process in acetone ultrasonic bath. Atomic force microscopy (AFM) image of the final sample structure are shown in Figure1.

In the hysteresis loop, obtained by Vibrating Sample Magnetometry (VSM), was made in two distinct configurations with external magnetic field applied along 0º and 45º in relation to a horizontal side. The measurements show the square-like shape of the hysteresis loop and an increase of the coercive field, when external field is applied on the sample diagonal 45º instead of aside the square pattern 0º. From micromagnetic simulations performed with computational codes provided by the Object Oriented MicroMagnetic Framework (OOMMF) [6] we found good agreement between experimental and computational hysteresis loop. So we could investigate the spin configuration in different stages of the hysteresis curve. Furthermore, these simulations revealed the existence of an array of crystal vortices (Figure 2a) with random polarization and chirality (Figure 2b).

In order to investigate the topological crystal vortex magnetization by magnetoresistive measurements were realized, with external magnetic field applied in configuration longitudinal (Figure 3a), transversal and perpendicular to the 8.1 mA applied current. The main magnetoresistive peak observed is attributed to the randomic orientation of vortex crystal polarization and chirality at zero field, causing increase in resistance due to higher density of scattering and spin mixing. The saturation of magnetization in longitudinal and transversal configuration or vortex core orientation with external field out of plane (perpendicular), providing low resistive path and consequently low resistance. It is worth mentioning that, the anisotropic behavior expected for nickel thin films can be observed just in the zoom around the curve peak (Figure 3b).

The crystal vortices pattern observed in the electrically connected propose antidote-ASI system suggest it as promising for further investigations and applications in future spintronics. References

[1] M. Rahm, J. Stah, and D. Weiss, Appl. Phys. Lett., 87 (2005) 182107. [2] J. Iwasaki, M. Mochizuki, and N. Nagaosa, Nat. Nanotechnol., 8 (2013) 742. [3] P. Tartaj, Encycl. Nanosc. Nanotech. 6 (2004) 823. [4] R. F. Wang, C. Nisoli, R. S. Freitas, J. Li, W. McConville, B. J. Cooley, M. S. Lund, N. Samarth, C. Leighton, V. H. Crespi, and P. Schiffer, Nature, 439 (2006) 303. [5] C. I. L. de Araujo, R. C. Silva, I. R. B. Ribeiro, F. S. Nascimento, J. F. Felix, S. O. Ferreira, L. A. S. Mól, W. A. Moura-Melo, and A. R. Pereira, Appl. Phys. Lett., 104 (2014) 092402.

[6] M. J. Donahue and D. G. Porter, OOMMF v1.2a3 Object Oriented MicroMagnetic Framework, Software (NIST, 2004). Figures

Figure 1. AFM image of the antidot lattice sample that are holes and their array mimics the artificial spin ice geometry.

Figure 2. We show the results from simulation in OOMMF of 9 cells revealing the vortex-crystal chiralities in (a) and core polarizations represented by black and white central spots in (b).

Figure 3. The magnetoresistive measurement with external magnetic field applied in configuration longitudinal (a) and zoom of peak (b).

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Synthesis of High Effective Surface Area Silver Nanoparticles Embedded in Porous Alumina Matrix Using the Melt Spinning Process

Isaac Rodríguez Pérez, Luís Frederico Pinheiro Dick

Lab. de Processos Eletroquímicos e Corrosão (ELETROCORR), Depto. de Metalurgia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Bl. IV-75, 91501-970, Porto Alegre, Brazil

[email protected], [email protected]

Abstract One of the most relevant uses for the Ag NPs (nanoparticles) is their application on the industry as catalytic material [1, 2]. The catalytic activity of the Ag NPs directly depends on the particle sizes and their distribution [3]. The chemical reduction approach is considered as the most appropriate technique to produce large quantities of nanoparticles with controlled size [4, 5]. Hence, is important to understand that this method uses reactants that can provoke potential risks for the environment and health [5]. The porous anodization of aluminum followed by electrodeposition is a well-known process to obtain metal nanoparticles or nanowires of noble metals as silver [6 8]. In the present work, we developed a new route for the fabrication of Ag nanoparticles embedded in a dielectric matrix (alumina) by the two-step porous anodization of a thermally treated (quenched) alloy using the melt spinner technique. A pro-eutectic Al-Ag alloy (95.25 %wt. Al) was molten and gradually heated to 780 °C using an induction oven and kept at that temperature for 20 minutes before quenching in the melt spinner. Then, a porous anodization process was performed in order to obtain a highly ordered nanotube array. The anodization was performed in 0.3 M oxalic acid solution applying a current density of 50 mV·cm-2 for 15 minutes. The structure and morphology of the aluminum oxide with precipitated silver were characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Fig. 1A shows the SEM image of the surface of the anodized sample evidencing the presence of eutectic Ag in a lamellar structure alongside Ag NPs with a mean diameter of 100 nm on top of the aluminum oxide layer. The cross-section (Fig. 1B) shows that the Al2O3 nanotubes formed during the anodization are 9.7 µm long and 200 nm wide, with incrusted Ag NPs on the regular nanotubular layer. The aluminum oxide layer was physically separate by stripping and characterized by TEM. Fig. 2A shows a typical formed nanotube with a mean diameter of 200 nm. On top of the nanotube Ag NPs are present with a diameter varying from 7 to 18 nm. The TEM/EDS elemental composition analysis that was performed (Fig. -Ag,

contain 99 %at. of silver. The size distribution of the Ag NPs determined by TEM imaging of the surface (Fig. 3A) showed that 95% of the Ag NPs have equivalent diameters smaller than 40 nm, ranging the diameters between 4 and 87 nm, as seen in the histogram of Fig. 3B. Moreover, it is noteworthy that 50% of the nanoparticles have an equivalent diameter between 4 and 10 nm. Consequently, it is confirmed that by a new route evolving porous anodization Ag NPs with sizes ranging between 4 and 87 nm can be produced randomly dispersed on a porous aluminum oxide surface. References [1] McFarland AD, Van Duyne, RP, Nano Letters, 3 (2003) 1057-1062. [2] Köhler JM, Abahmane L, Wagner J, Albert J, Mayer G, Chemical Engineering Science, 63 (2008) 5048-5055. [3] Zhang J, Chen P, Sun C, Hu X, Applied Catalysis A: General, 266 (2004) 49-54. [4] Leopold N, Lendl BA, The Journal of Physical Chemistry B, 107 (2003) 5723-5727. [5] Zhang W, Qiao X, Chen J, Materials Science and Engineering: B, 142 (2007) 1-15. [6] Huber CA, Huber TE, Sadoqi M, Lubin JA, Manalis S, Prater CB, Science, 263 (1994) 5048-5055. [7] Yi JB, Pan H, Lin JY, Ding J, Feng YP, Thongmee S, Liu T, Gong H, Wang L, Advanced Materials, 20 (2008) 1170-1174. [8] Zhang J, Kielbasa JE, Carroll DL, Materials Chemistry and Physics, 122 (2010) 295-300.

Figures

Figure 1. (A) SEM image of the oxide surface containing Ag NPs. (B) Cross-section SEM image of formed Al2O3 nanotubes.

Figure 2. (A) TEM image of formed Al2O3 nanotubes with embedded silver nanoparticles. (B) TEM image of nanotube showing the areas of EDS analysis. The insert shows the obtained spectra.

Figure 3. (A) Area selected for the distribution analysis by TEM and (B) histogram of the frequency per area versus the equivalent diameter of the silver nanoparticles and the cumulative probability.

Resistive switching and impedance spectroscopy in metal-oxide-metal trilayers with SiOx and ZrO2: a comparative study

C.M.M. Rosário

a, O.N. Gorshkovb, A. Kasatkinb, I. Antonovb, D. Korolevb, A.N. Mikhaylovb, N.A. Soboleva,c

aDepartamento de Física and I3N, Universidade de Aveiro, 3810-193 Portugal

bLobachevsky State University of Nizhni Novgorod, 603950 Russia c

[email protected]

Abstract

The ReRAM, acronym of resistive (switching) random access memories, are candidates to lead the new generation of non-volatile memories and are based on a phenomenon known as resistive switching (RS) [1]. The research on this [2], was boosted by the link to the memristor, a passive fundamental circuit element proposed by Leon Chua in 1971 [3], demonstrated by a group of the HP Labs in 2008 [4]. Although the titanium dioxide is considered a prototypical memristive material [5], research on RS in structures containing materials that are compatible with the CMOS technology, nowadays the leading technology in the fabrication of integrated circuits, such as silicon oxide or zirconium oxide, may favour the future market introduction of RS-based devices.

In this work, Au/oxide/TiN structures, obtained by RF-magnetron sputtering deposition of 40 nm thin films of silicon and zirconium oxides, were investigated by means of current-voltage (I-V) characteristics and impedance spectroscopy and compared based on the results obtained.

In the SiOx structure, the I-V characteristics exhibit bipolar-like RS, with a ratio between the resistances of the high resistance state (HRS) and the low resistance state (LRS) bigger than 102, at 1 V read voltage. The observed RS is sensitive to the Au electrode exposure to the atmosphere, which enhances the RS (see Fig. 1). A decrease in the voltage application time leads to an increase in the voltage required to induce the transition from HRS to LRS. The two different states show a very distinct behaviour as the temperature is varied: whereas the LRS's resistance has a very weak temperature dependence and decreases with decreasing temperature, in the HRS the resistance increases as the temperature drops. The latter state's resistance temperature dependence is described by a thermal activation of charge carriers, with activation energies of 0.46 and 4.3 meV in the 6 to 130 K temperature region. The weak dependence of the resistance with the Au electrode area and the invariance of the structure's capacitance between the states suggest a filamentary mechanism for the observed RS. Due to the oxygen's influence on the RS, the creation and disruption of the filaments should involve redox reactions.

The ZrO2 structures also exhibit bipolar-like RS, with a ratio of ca. 102 between the resistance of the HRS and of the LRS, read at 1 V. However, the atmospheric exposure decreases the above mentioned ratio, having the opposite effect on the RS, relatively to the SiOx case (see Fig. 2). The increase in this ratio via pulsed measurements evidences the existence of at least two competing processes in the RS. The impedance spectra show a similar behaviour between these structures and the SiOx ones, even though there is a bigger dependence on the electrode area, behaviour that deviates from a single filament model. The addition of a germanium oxide (GeOx) layer between the Au electrode and the ZrO2 film enhances the repeatability of the I-V characteristics. References [1] D. S. Jeong, R. Thomas, R. S. Katiyar, J. F. Scott, H. Kohlstedt, A. Petraru, C. S. Hwang, Rep. Prog. Phys., 75 (2012): 076502. [2] T. W. Hickmott, J. Appl. Phys., 33 (1962): 2669 2682. [3] L. Chua, IEEE Trans. circuit theory, CT-18 (1971): 507 519. [4] D. B. Strukov, G. S. Snider, D. R. Stewart, R. S. Williams, Nature, 453 (2008): 80 83. [5] K. Szot, M. Rogala, W. Speier, Z. Klusek, A. Besmehn, R. Waser, Nanotechnology, 22 (2011): 254001.

Figures

-6 -4 -2 0 2 4 610-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

I (

A)

V (V)

Without SiO2 mask

With SiO2 mask

LRS

RE

SE

T

SET HRS

Initial direction

Fig. 1: Typical I-V characteristics obtained for the Au/SiOx/TiN structures with a voltage sweep rate of ca. 1 V/s. The data displayed with the empty symbols was measured with a 300 nm-SiO2 mask covering the Au electrode, evidencing the importance of the atmospheric exposure for the RS process in increasing the resistance ratio between the high resistance state (HRS) and the low resistance state (LRS). The red dashed arrow indicates the initial direction of measurement.

-6 -4 -2 0 2 4 610-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

I (

A)

V (V)

Without SiO2 mask (cont.)

With SiO2 mask (cont.)

Without SiO2 mask (puls.)Initial direction

SET

LRSRESET

HRS

Fig. 2: Typical I-V characteristics obtained for the Au/ZrO2/TiN structures with a voltage sweep rate of ca. 1 V/s (for the data shown with the circular symbols). The data displayed with the empty symbols was measured with a 300 nm-SiO2 mask covering the Au electrode, evidencing the impact of the atmospheric exposure for the RS process, in this case decreasing the resistance ratio between the high resistance state (HRS) and the low resistance state (LRS). The data displayed with the triangular symbols were measured in a pulsed regime (with a voltage sweep with 500 s pulses for each voltage level, intercalated with a time interval where there was no applied voltage), which enabled a higher resistance ratio even without the mask. The red dashed arrow indicates the initial direction of measurement.

Nanoencapsulation improves the antibactericidal effect of

docosahexaenoic acid against Helicobacter pylori

Catarina L. Seabra1,2,3,4, Cláudia Nunes5, Marta Correia1,3, José Carlos Machado1,3,6, Celso Albuquerque

Reis1,3,4,6, Inês C. Gonçalves1,2, Salette Reis5, M Cristina L Martins1,2,3

1Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal, 2INEB - Instituto de Engenharia Biomédica,

Universidade do Porto, Portugal, 3IPATIMUP Instituo de Patologia e Imunologia Molecular da Universidade do Porto, Portugal, 4ICBAS- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Portugal, 5REQUIMTE, Laboratório de Química

Aplicada, Faculdade de Farmácia, Universidade do Porto, Portugal, 6Faculdade de Medicina, Universidade do Porto, Portugal

[email protected]

Abstract

Introduction

Helicobacter pylori (H. pylori) is a gram-negative, microaerophilic and spiral-shaped bacterium

H. pylori infection

recommended treatment is based in a combination of at least two antibiotics and a proton pump

inhibitor [2]. However, this therapy fails in 20% of patients especially due to bacterial resistance [3].

It was previously demonstrated that a lipophilic compound, docosahexaenoic acid (DHA), an

omega-3 polyunsaturated fatty acid present in fish oil, decreases H. pylori growth in vitro in a dose-

dependent way and inhibits mice gastric colonization in vivo. However, up to 40% of infected mice,

following DHA treatment, are still colonized by bacteria [4]. This might be explained by the low

penetration of DHA through the stomach mucus layer, which leads to an insufficient concentration of

DHA to eradicate H. pylori at the infection site. This work aims the development of a DHA gastric

delivery system to improve its efficacy against H. pylori.

Materials & Methods

DHA was incorporated into nanostructured lipid carriers (NLC), submicron colloidal carriers

composed of biodegradable and biocompatible lipids recognized for the incorporation of lipophilic

and poorly water-soluble drugs [5]. NLCs with different DHA concentrations (0, 1, 2 and 2.5% v/v)

were produced by hot homogenization technique using a mixture of mono-,di- and triglyceryl esters

of palmitic and stearic acids as solid lipids, a liquid lipid and polysorbate 60 as the stabilizer. NLCs,

with and without DHA, were characterized by dynamic light scattering (DLS) in Milli-Q water at 37ºC,

and DHA incorporation was quantified using UV-Vis spectroscopy (200-400nm) after dissolution in

ethanol.

The effect of DHA-NLC on H. pylori J99 strain growth was evaluated during 24h, at 37ºC, 150

rpm, under microaerophilic conditions using an initial bacteria concentration of ~1x107 bacteria/ml in

Brucella Broth medium (BB) supplemented with 10% of Fetal Bovine Serum (FBS). Different

concentrations of DHA-NLCs (50, 100 and 500 µM) prepared with 2% v/v DHA were tested. DHA in

solution and NLCs without DHA were used as control. After different time-points, a sample of each

bacterial culture was collected and plated on H. pylori selective solid medium. Number of viable

bacteria was determined by colony forming units (CFU) counting.

Cytotoxicity of DHA-NLCs towards MKN45 gastric carcinoma cell line was performed using 3-

(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase

leakage (LDH) assays. MKN45 cells were seeded in concentration of 5x105 cells per well in RPMI

1640 with glutamax and HEPES, supplemented with 10% inactivated FBS and 1% PenStrep at 37ºC

in humidified 5% CO2 atmosphere, during 48h. Then, different concentrations of NLCs and DHA-

NLCs (10, 25, 50 and 100 µM), prepared with 2% v/v DHA were added to 2 ml of final volume. After

24h, LDH and MTT assay were performed by measuring optical density at 490 and 630 nm and at

590 and 630 nm, respectively, using a microplate reader.

Results

All produced NLCs have a size of 150-250 nm, negative zeta potential (~ -30 mV) and a DHA

entrapment efficiency higher than 50% independently on DHA amount added.

Experiments performed with H. pylori demonstrated that NLCs without DHA have a bacteriostatic

effect, inhibiting bacterial growth, whereas all concentrations of DHA-NLC tested are bactericidal

against H. pylori even at the lower DHA concentration used (50 µM) in opposite to DHA in solution

that could not kill bacteria at concentrations lower than 100 µM.

Cytotoxicity studies revealed that all NLCs tested (with and without DHA) are non-cytotoxic for

gastric cells at concentrations up to 50 µM.

Conclusion

In conclusion, NLCs nanoparticles can be used to encapsulate DHA improving its bactericidal

effect on H. pylori. These nanoparticles are not cytotoxic against gastric cells at bactericidal

concentrations. DHA-loaded NLC should therefore be considered as an alternative to the current

treatment of H. pylori.

References

[1] Wroblewski et al.; Microbiol Rev; 23 (2010):713-39

[2] Malfertheiner et al.; Gut; 61 (2012):646-64

[3] Vakil; Am J Gastroenterol; 101 (2006):497-9

[4] Correia et al.; PLoS One; 7 (2012): e35072

[5] Battaglia & Gallarate; Expert Opin Drug Deliv; 9 (2012): 497-8

An Improved Wet Chemical Approach For The Separation Of

Graphene From Nickel Foil To The Reutilization Of Catalyst

Choon-Ming Seaha,b, Brigitte Vigoloa, Siang-Piao Chaic, Abdul Rahman Mohamedb.

a Institut Jean Lamour, CNRS-Université de Lorraine -lès-Nancy, France

b School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal,

Seberang Perai Selatan, P. Pinang, Malaysia

c Chemical Engineering Discipline, School of Engineering, Monash University, Jalan Lagoon Selatan,

46150 Bandar Sunway, Selangor, Malaysia

Email: [email protected]

Abstract

Chemical Vapor Deposition (CVD) is the most widely studied approach for the synthesis of wafer scale graphene. To fully utilize the magnificent properties of the graphene, the separation of graphene from the metal catalyst is important. To date, majority of the studies utilizing the wet chemical etching method that scarifying the metal catalyst in order to obtain free standing graphene. In order to realize the re-use of catalyst for minimization of the waste, an improved simple wet chemical etching method approach is proposed. Nickel has relatively high carbon solubility under elevated temperature as compared with other catalyst. Part of the carbon dissolved in the bulk nickel was not been used for the formation of graphene and later reacted with nickel to form nickel carbide crystal. After CVD, the nickel foil with graphene was floated onto iron nitrate solution with concentration of 1 mol/dm3, an etching agent. The etching agent would intercalate between graphene and nickel to etch the surface of nickel for separation under slower rate. The inertness of nickel carbide would act as the protective layer to slowdown the chemical attack onto the bulk nickel foil and preserve it. The remaining nickel foil after the separation was used for same CVD and separation process to obtain another layer of graphene. A nickel foil with a thickness of 125µm can be reused to synthesis up to 6 pieces of graphene without large deviation in properties.

Large power emission in MTJ based spin torque nano-oscillators using a free layer near the in-plane to out-of plane transition

M. Tarequzzaman, J. D. Costa, J. Borme, M. Gonzalez-Debs, B. Lacoste, E. Paz, S. Serrano-Guisan,

R. Ferreira and P. Freitas. INL-International Iberian Nanotechnology Laboratory, Avenida Mestre Jose Veiga,

4715-330, Braga, Portugal [email protected]

Spin torque nano-oscillator (STNO) explore dynamic magnetic effects induced in the free layer of magnetoresistive devices induced by spin polarized currents. Soon after its discovery, STNO draw much attention to the researchers because of its advantages over conventional CMOS oscillators. The advantage of STNO covers, simple structure, smaller footprint (<200nm), high frequency tunability, large frequency (2-20 GHz range oscillations depending on magnetic field), low cost and good compatibility with the standard complementary metal oxide semiconductor (CMOS) technology.[1-3]However several challenges need to be addressed before STNOs are to be used in practical purpose. As it has critical disadvantages in terms of lower output power and relatively large linewidth in comparison with voltage controlled oscillators (VCOs).[4] The power generation of STNO depends on several factors; resistance change induced by the magnetoresistance (MR) effect in the magnetization oscillations is one of them. Therefore, MgO based magnetic tunnel junctions (MTJs) with higher MR ratio (>50%) deliver larger microwave signals than metallic oscillators with lower MR ratio (<10%).[3] In addition to this, another requirement for a large power emission is the excitation of large-amplitude oscillations. To this end, several configurations for the magnetization of the free and pinned layer have been proposed. In this work, MTJ stacks (50 Ta/ X CoFe40B20/MgO [3.0 Ohm-µm2]/2.2 CoFe40B20/0.85 Ru/2.0 CoFe30/20 IrMn (Thickness in nanometer) with an MgO barriers have been deposited using a Singulus TIMARIS PVD system. The free layer thickness (X) was changed between 2.0nm (free layer magnetization in plane) down to 1.0nm (free layer magnetization perpendicular to plane). These stacks were then patterned into nanopillars with different shapes (circular and elliptical) and dimension (50 nm to 200 nm in diameter) by electron beam lithography and ion milling technique. The nano-pillars have been measured in a radio frequency transport measurement setup at room temperature. It is found that a large power output with a small linewidth is obtained in nano-pillars with a free layer thickness of 1.4nm which still have an in-plane magnetization but right at the transition to out-of-plane magnetization, i.e., the in-plane free layer experiences a very strong perpendicular anisotropy contribution. An example of such measurements is shown in Fig. 1.a. for a pillar with circular shape and 150nm diameter. The result, show in Fig. 2, displays microwave signals with maximum power of 300 nW and narrow linewidth as small as 30 MHz. These STNOs operate with frequencies in the range between 2.4-2.8GHz .The large power output and narrow linewidth of these nano-oscillators make them good candidates for integration with CMOS circuits such as new generation Phase-Locked-Loops (PLLs).

References:

[1] Z. Zeng, G. Finocchio, B. Zhang, P. K. Amiri, J. A. Katine, I. N: Krivorotov, Y. Huai, J. Langer, B. Azzerboni, K. L. Wang, and H. Jiang, Sci. Rep. 3, (2013) 1426 [2] S. I. Kiselev, J. C. Sankey, I. N. Krivorotov, N. C. Emley, R. J. Schoelkopf, R. A. Burman, D. C. Ralph, Nature. 425, (2003), 380 383. [3] Z. Zeng, P. K. Amiri, I. N. Krivorotov, H. Zhao, G. Finocchio, J.-P. Wang, J. A. Katine, Y. Huai, J. Langer, O. K Galatsis, K. L. Wang, and H. Jiang, ACS Nano 6, (2012) 6115 6121 [4] H. S. Choi, S. Y. Kang, S. J. Cho, I. Y. Oh, M. Shin, H. Park, C. Jang, B. C. Min, S. Kim, S.Y. Park, C. S. Park, Sci. Rep. 4, (2014) 5486

Figure1: a) Illustration of radio frequency (RF) measurement setup. b) The measured MTJ stack and nanopillar dimension.

Figure2: a) Transport measurement (two contact measurement) in easy and hard axis. The arrow indicating the RF measurement point b) Microwave emission spectra measured in positive bias currents (Black spectrum) and negative bias currents (Red Spectrum). c) Shows the results, in terms of power emissions, linewidth, frequency tunability and resistance.

RA ~ 3 m2

Circular 150 x 150 nm2

FL thickness ~ 1.4 nm

a)

b)

a)

2 4 6 8

0

4

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f (GHz)

PS

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V2 /H

z)

x10

Ibias

= +1.25 mA

360

380

-2 -1 0 1 20

150

300

200

400

2.4

2.8

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)

Ibias

(mA)

P (n

W)

(MH

z)

f (G

Hz)

-1 0 1

350

400

hard axis

R (

)

Field (A)

easy axis

b) c)

Spin-orbit coupling in graphynes

Guido van Miert, Cristiane Morais Smith, and Vladimir Juricic

Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, Utrecht, The [email protected]

Abstract Graphynes represent an emerging family of two-dimensional carbon allotropes that recently attracted much interest due to the tunability of the Dirac cones in the band structure. We explore the effects of spin-orbit couplings, both Rashba and intrinsic ones, in these systems. First, we develop a general method to address spin-orbit couplings within tight-binding theory. We then apply this method to describe the effects of spin-orbit

couplings in , , and -graphyne. We show how spin-orbit couplings can lead to various effects related to both topological and non-topological properties of their band structures. In -graphyne, as in graphene, the Rashba spin-orbit coupling splits each Dirac cone into four, whereas the intrinsic spin-orbit coupling opens a topological gap. In -graphyne, intrinsic spin-orbit coupling yields high- and tunable Chern-number bands, which may host both topological and Chern insulators, in the presence and absence of time-reversal symmetry, respectively [1]. On the other hand, Rashba spin-orbit coupling can be used to control the position and the number of Dirac cones in the Brillouin zone. Finally, the Rashba spin-orbit coupling can close the band gap in -graphyne [2].

References

[1] G. van Miert, C. Morais Smith, and V. Juricic, Phys. Rev. B. 90, 081406(R) (2014).

[2] G. van Miert, V. Juricic, and C. Morais Smith, arXiv:1409.0388 (Accepted into Phys. Rev. B)

Synthesis and characterisation of graphite oxide/vanadate nanowire composites

,1 Henrik Haspel,1 1,2 1,2,3

1Department of Applied and Environmental Chemistry, University of Szeged, , H-6720 Szeged, Hungary



[email protected]

Abstract

There is a growing interest in composites composed of vanadium-oxides and carbon nanostructures due to their promising electrochemical properties. These composite materials are potential candidates for application as electrode materials in Li-ion batteries and supercapacitors [1,2]. The latter have thousand times higher specific capacity than conventional electrolytic capacitors, while its performance deteriorates only slightly during hundreds of charge-discharge cycles. In our study vanadate nanowire graphite oxide composites were synthesized via the hydrothermal route. The influence of adding graphite oxide to the composite on the electrochemical performances was investigated. The morphology, structure and interaction between components were studied by transmission and scanning electron microscopy (TEM, SEM), Raman spectroscopy, X-ray diffractometry (XRD) and energy dispersive X-ray spectrometry (EDS). The electrochemical properties were examined by the galvanostatic charge-discharge method, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacity, energy and power density of the capacitor constructed from the vanadate/graphite oxide composites were determined and their dependence on the amount of added graphite oxide was discussed.

Results revealed that a hybrid type supercapacitor was formed. The specific capacities determined from cyclic voltammetry and galvanostatic charge-discharge method were in good agreement and were found to increase monotonously between 210 and 270 F/g with increasing amount of graphite oxide. The energy density of the capacitor changed from 19 to 25 Wh/kg with the graphite oxide content, however, power density turned out to be independent of the graphite oxide amount at around 410 W/kg. These values are in good agreement with literature data. On the other hand, the mechanism responsible for the considerable deterioration of specific capacity during repeated charge-discharge cycles is yet to be resolved. References [1] Bonsoa, J.S.; Rahya, A.; Pereraa, S. D.; Nourb, N.; Seitz, O.; Chabalb, Y.J.; Balkus Jr., K.J.; Ferraris, J.P.; Yang, D.J. J. Power Sources, 203 (2012) 227 232. [2] Liang, S.; Zhou, J., Fang, G.; Zhang, C.; Wu, J.; Tang, Y.; Pan, A. Electrochim. Acta 130 (2014) 119 126.

XPS and VUV studies of N-doped TiO2 Sol-Gel Films

H. C. Vasconcelos1,2 and F. Rivera-López

1 Azores University, Department of Science Technologies and Development, Campus de Ponta Delgada, PT - 9501-801 (Ponta Delgada), Açores, Portugal

2 CEFITEC - Centre of Physics and Technological Research, Physics Department of FCT/UNL, Quinta da Torre, 2829-516 Caparica, Portugal

3 Department of Fundamental and Experimental Physics, Electronics and Systems, University of La Laguna, Tenerife 38206, Spain

Corresponding author: H.C. Vasconcelos (Tel.: +351 296 650 170), email: [email protected]

Information about the structural environment of nitrogen anions in TiO2 host matrices is necessary in

order to tailor a glass composition with optimized spectral properties for photocatalytic applications.

The present study is aimed at determining the influence of the N ions on the structural glass

environment around Ti cations in amorphous TiO2 matrices (oxynitride films). For this purpose, thin

film samples of TiO2-xNx compositions, with N concentrations up to x = 0,75 (25 at.%), were prepared

by sol-gel processing followed by spin-coating onto Si(100) wafers, glass slides and CaF2 substrates.

The samples were then studied by X-ray photoemission spectroscopy (XPS) and Vacuum ultraviolet

(VUV) light scattering, after being annealed up to 500°C. These measurements allowed the

determination of the concentrations of the different Ti-O-Ti, N-Ti-O and Ti-N-Ti bonding sequences.

XPS data were correlated to thermal behavior and optical properties. Photoabsorption spectra of

oxynitride thin films are reported in the energy range 3.9 10.8 eV (320 115 nm). Electronic state

assignments have been suggested for each of the observed absorption bands.

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Cover image: p-Type Cu2O colloids optimized for photoelectrochemistry and electronics

Credit: Yury V. Kolen’ko (International Iberian Nanotechnology Laboratory -INL, Portugal)

Edited by

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Deposito legal / Spanish Legal Deposit: BI-168-2015

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www.phantomsnet.net

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