Diapositiva 1
Quantum dots and their interaction with DNA
05.04.2013.Nzev:
kolitel: Datum:Stanisavljevi Maja
Reg..projektu: CZ.1.07/2.3.00/20.0148Nzev projektu: Mezinrodn spoluprce v oblasti "in vivo" zobrazovacch technikQuantum dots history of synthesis
1980 Ekimov, Efros first description of quantum dots 1993 - Murray, Norris, Bawendi CdE(E=S,Se,Te) and other improvments like ZnS shellSemiconductor nanocrystals synthetized from II and VI or III and V elements of PSE. today-enviromental-friendly synthesis
CdTeZnS
Characteristics
small size 1-10nm absorbtion of light in wide range emmision range very narrow photostability and resistance to chemical degradation poisonous core and hydrophobic surface modification bioconjugation
DNA
1869 isolated by Swiss scientist Friedrich Miescher 1953 described DNA structure Watson and Crick 1962 they recieved Nobel prize for solving natures biggest secretDNA helix-two complementary and antiparallel polynucleotide strands
QDExperiment hypothesis:
Major groove 2.2 nmQD-GSH 2 nmDNA invisible for CE-LIFMix DNA and observe
Measurements conditions
CE-LIFCapillary lenght: ltot= 57 cm, leff = 50 cm, ID = 75 mBGE: 20 mM borate pH 9.2Separation: 20 kV, positive polarityInjection: 3.4 kPa for 20 secExcitation wavelenght: 488 nmEmmision wavelenght: 520 nmSample: QD-GSH and DNA from chicken in conc. of 1 mg/mL
QD-GSHMigration time (min)If (a.u)CE-LIF QD-GSHMigration time (min)If (a.u.)heated QDs 10 min at 50oCSize (nm)Intensity %ex = 380 nmem = 524 nmQD-GSH + DNA interaction through time
Migration time (min)IF (a.u.)
QD
QD
Concentraton of DNA (mg/mL)Height of peak
Time of migration (min)IF (a.u.)QD-GSH with different concentration of DNA
DNA 1 0.25 mg/mLDNA 2 0.50 mg/mLDNA 3 1.00 mg/mL
QD-GSH + DNA 1QD-GSH + DNA 2QD-GSH + DNA 3QD-GSHQD-GSH - dsDNA vs ssDNA
Migration time (min)IF (a.u.)QDsQDs + ssDNAQDs + dsDNANo complex
ssDNAdsDNAQD-GSH - hybridization of DNA
Hybridization of DNK: 99oC, 15 minMigration time (min)IF (a.u.)ConclusionsQDs and dsDNA interacts creating complex in shape of peak
Interaction peak grows through time and increasing DNA concentration
Complex is not created with ssDNA or hybridized dsDNA possible confirmation of QDs being caught in major groove
Some QDs with different capping agents
Thanks to :
Departament of chemistry and biochemistryJana Chomoucka for QD preparing
THANKYOUFORATTENTION!