Introduction to BioMEMS

Group 5

電機三 蔡承佑

電機三 許博竣

電機三 許秉鈞

What is MEMS?

Micro

Systems

Electro Mechanical

1-100μm size by

microfabrication

Consist of electromechanical

sensors/actuators

Integrated multiple elements

to perform multiple tasks

What is Bio-MEMS?

• A special class of MEMS devices or components used in life sciences

• Application of MEMS in biomedical field

MEMS vs. BioMEMS

MEMS BioMEMS

inertial sensor pacemaker

pressure sensorblood pressure

monitor

electroacoustic

devicehearing-aid

microneedles drug delivery

Areas of Applications

• Detection

• Analysis

• Diagnosis

• Therapeutics

• Drug delivery

• Cell culture

Examples of BioMEMS Devices

• Retina Array

• Lab-on-a-chip

• Micro-pump

• Tactile Sensor Array

• Chemical Sensor Array

• Microfluidics

• Cell Culture

• DNA Microarray

Examples of BioMEMS Devices

Retina Array

Lab-on-a-chip

Examples of BioMEMS Devices

Micro-pump

Tactile Sensor Array

Examples of BioMEMS Devices

Chemical Sensor Array

Microfluidics

Examples of BioMEMS Devices

Cell Culture

DNA Microarray

ApplicationsArtificial Retinal Prosthesis

Artificial Retinal Prosthesis-Intro

• Argus™ Retinal Prosthesis

System

• photoreceptor cells →an

electrode array

• Directly on the retina at the

back of the eye

How Does It Work?

Results

Argus IIIArgus IIArgus I

Microfluidics-Intro

• Separations, chemical reactions, and calibration-free

measurements with minute quantities of complex

samples

• Manipulating and controlling fluids(between 10-6 to

10-12 L)

• Dimensions from ~10-100 μm

Probing CTC in Microfluidics

• Using non-destructive ultrasound waves to separate CTCs

• Two acoustic transducers + a small channel

• Standing wave

• 83 % of CTCs seperated

Lab on a chip

LOC definition

• a device that integrates one or several laboratory functions on a single integrated circuit

• a subset of micro-electro-mechanical systems (MEMS)

• sometimes called Micro Total Analysis Systems, µTAS, but sometimes they are different

BioMEMS Venn Diagram

What’s LOC?

• Miniaturization and integration of

laboratory sample preparation

processes

• Consists of microfluidic channel,

microsensors and microacutator

• Reduce cost and waste of

biodiagnostics

• Personalized healthcare and medicine

Body parts on a chip

Geraldine Hamilton: Body parts on a chip

https://www.youtube.com/watch?v=CpkXmtJOH84

Chip Fabrication

Design, fabrication and cell-handling of microfluidic device for single cell electroporation

https://www.youtube.com/watch?v=Hf0sen7bJ6A

molding

Micromolding - Injection

Design, fabrication and cell-handling of microfluidic device for single cell electroporation

https://www.youtube.com/watch?v=Hf0sen7bJ6A

Issues:

• Incompatible to brittle silicon

• Expensive

• Thermal expansion

• Hazardous vapor during heating

Photolithography Process

Design, fabrication and cell-handling of microfluidic device for single cell electroporation

https://www.youtube.com/watch?v=Hf0sen7bJ6A

Soft lithography

Design, fabrication and cell-handling of microfluidic device for single cell electroporation

https://www.youtube.com/watch?v=Hf0sen7bJ6A

• (a) – (d): fabrication of a rigid

master via photolithography.

• (e) and (f): considered as part of

the soft lithography process

PDMS Soft lithography

1. Microcontact printing: (stamp)

The PDMS layer is first soaked in a molecular “ink” and then

brought into contact with a substrate in order to transfer the

ink onto the substrate surface.

2. Capillary molding

The patterns of the PDMS layer must first be brought into contact

with a substrate (e.g. a glass slide). Capillary molding is then

intended to fill the patterns of the PDMS mold with a liquid polymer.

-> Will Be Discussed Later!

Fabrication Methods1. Chemical Etching

(e.g. Wet chemical etching of silicon)

(1) Diffusion of the liquid etchant to the structure

that is to be removed.

(2) The reaction between the liquid etchant and

the material being etched away

(3) Diffusion of the byproducts in the reaction

from the reacted surface.

2. Reactive-ion Etching

• based on Dry Etching (ion plasma)

• Etching gas is into the chamber

• RF power connected below

• Byproduct desorbed from surface

• Byproduct exhausted from chamber

Body parts on a chip

Geraldine Hamilton: Body parts on a chip

https://www.youtube.com/watch?v=CpkXmtJOH84

Organ-on-a-chip

Membrane: a porous, flexible membrane in the center, on which we could add “real” human

cells, like lung cells or skin cells

Capillary cells: underneath the membrane are the capillary cells, which is the cells in our blood

vessels.

Vacuum Channel: there exists two vacuum channels which are marked gray, that can

mechanically add forces with an aim to stretch and contract the membrane, just like what we do

when breathing.

Finally, we pump some air and some liquid with nutrients, for simulating human blood, into the

chips.

Organ-on-a-chip

Functionality

Geraldine Hamilton: Body parts on a chip

https://www.youtube.com/watch?v=CpkXmtJOH84

Customized cures

• Custom cures for one specific person, especially children are indeed helpful

• In the past days, we could only use adults’ data to deal with children cases

• With this technology, we could make highly varied chips which depends on every individuals’, custom cures and

thus provided.

LOC Summary

• low fluid volumes consumption

• faster analysis and response times due to short diffusion

distances, fast heating, high surface to volume ratios, small heat

capacities.

• better process control because of a faster response of the system

• massive parallelization due to compactness

• lower fabrication costs, allowing cost-effective disposable chips

• safer platform for chemical, radioactive or biological studies

References

• http://scme-nm.org/files/SCME_MNT_BioMEMS_Workshop.pdf

• http://electroiq.com/blog/2013/10/mems-devices-for-biomedical-applications/

• https://share-ng.sandia.gov/news/resources/releases/2002/mat-chem/blindsee.html

• http://www.genengnews.com/market-and-technology-analysis/microfluidics-in-the-life-sciences/77900586

• http://biopoets.berkeley.edu/cell-culture-array/

• http://libertgen564s15.weebly.com/microarray.html

• https://www.bo.imm.cnr.it/unit/articles/mems-based-ultra-low-power-gas-sensors-and-detectors

References

• http://web.ece.ucdavis.edu/~anayakpr/Papers/Wet%20and%20Dry%20Etching_submitted.pdf

• http://www.elveflow.com/microfluidic-tutorials/soft-lithography-reviews-and-tutorials/introduction-in-soft-lithography/introduction-about-soft-lithography-and-polymer-molding-for-microfluidic/

• https://www.youtube.com/watch?v=CpkXmtJOH84

• http://dingspring.blogspot.tw/2012/03/dry-etching-rie-reactive-ion-etching.html

• www.pnas.org/content/112/16/4970.full.pdf