The Application Of Click Chemistry And Electrochemiluminescence Of Quantum Dot In Biosensors

Click chemistry is a rapid and reliable method to synthesize specific products byjoining small units together. One of the most popular reactions within the clickchemistry concept is the copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC).CuAAC is highly specific to the catalysis of copper (I) and is capable of high yieldunder mild reaction conditions with little by-product and simple operation.DNA-templated synthesis (DTS) modulates chemical reactions through thebase-pairing of DNA and improves the efficiency of organic reactions with an effectivecombination of organic chemistry and the characters of biochemistry. GO, a singlelayer two-dimensional carbon nanosheet, possesses a super-quenching capacity andapreferential binding ability of GO to ssDNA over dsDNA. Fluorescencespectrophotometry has been a widely used and appliable analytical technology.Quantum dots was the most attractive luminophor because of its high emissionquantum yield, wide excitation spectrum linewidth, narrow emission linewidth, thesize close to biological moleculars and surface functionalization. Theelectrochemiluminescence of quantum dots is a highly sensitive method and is apromising technique in bioanalytical chemistry.The main work of this thesis is summarized as follows:1. A novel DNA-templated click chemistry strategy for homogenous fluorescentdetection of Cu2+based on the selective quenching ability of graphene oxide (GO) tossDNA and dsDNA and the DTS-mediated DNA structure switch was proposed. In thepresence of Cu2+, the fluorescence intensity was obviously quenched. The mechanism,experimental conditions and quantitative detectionof Cu2+sensor of the system werestudied in the following chapter.2. A novel fluorescent biosensing strategy based on the DTS-induced generationof intramolecular G-quadruplex structure was studied. Crystal violet (CV) is chosen asa signal reporter due to that its fluorescence can be enhanced greatly via binding toG-quadruplexe in the presence of Cu2+. The mechanism, experimental conditions andquantitative detectionof Cu2+sensor of the system were studied in detail.3. A sensitive method for detecting alkaline phosphatase(ALP) based on theelectrochemiluminescenceof CdTe/ZnS quantum dots and the dephosphorylation ofALP was discussed. In the presence of ALP, the electrochemiluminescence of CdTe/ZnS quantum dots was obviously quenched by the phosphate, thedephosphorylation product of dTMP. The experimental conditions and quantitativedetectionof ALP sensor of the system were further studied.