Electrochemiluminescence Of Quantum Dots And Electrochemiluminescence Resonance Energy Transfer (ECRET) Of Quantum Dot-Cy5 System For DNA Analysis

The main research work is described as follows:In chapter one of this thesis-the ECL of QDs at the NPGL electrode and its biological application,the cathodic electrochemiluminescence (ECL) mechanism of mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) with S2O82- as coreactant at Au electrode was studied by cyclic voltammmetry.The maximum ECL intensity of CdTe QDs using S2O82- as coreactant is 2.7-fold higher than that using H2O2.When the new electrode material-nanoporous gold leave (NPGL) electrodes are used in the study, the sensitivity of the ECL method is remarkably increased due to ultra-thin nanopores. A new ECL bioassay mode is developed using CdTe QDs as labels of DNA at NPGL electrode. A linear relationship between Im,ECL and t-DNA concentration is obtained in a range of 5×10-15 to 1×10-11 mol/L and good reproducibility. The ECL DNA assay can be used to determine the DNA synthesized corresponding to cellular osteopontin (OPN) Mrna in this study.In chapter two-the ECRET of QD/K2S2O8-Cy5 system and its application, we reporte a novel resonance energy transfer (RET) technique, electrochemiluminescence resonance energy transfer (ECRET). ECRET mechanism of the QD-Cy5 system and biological applications of the ECRET technique were investigated and discussed. In ECRET, the emitters of QD/K2S2O8 system are generated at an electrode through electrochemical reaction and act as the electrochemiluminescent donors to emit light with a maximum emission of 590 nm. The fluorescent dye-Cy5, having a maximum emission at 675 nm were chosen as the acceptors. When a potential was applied to the electrode, the electrochemical donors transferred energy to the acceptors, producing efficient ECRET.We measured that the number of the DNA2-Cy5 connected to the QD-DNA1 is eight and the forster distance Ro for the QD-Cy5 couple is 3.56 nm.We found that the ECRET efficiency (ηE) of QD-DNA1-DNA2-Cy5 conjugate is related with the distance between QD and Cy5 and the number of the DNA2-Cy5 connected to the QD-DNA1.A linear relationship between Ipl and t-DNA moles is obtained in a range of 5.0×10-12 to 1.0×10-13mol. Using the ECRET bioassay mode,we also have measured the DNA conformational change uccessfully. To our knowledge, this is the first report on ECRET between luminescent QD donors and dye acceptors and its biological application.