Synthesis Of Low-toxicity Quantum Dots And CdSe@SiO₂and Their Electrochemiluminescence Immunoassay Application For Small Molecules

Nanoparticles-based electrochemiluminescence(ECL) technology has recently attracted a lot of attention. Different properties of nanoparticles have been reported, and its application in the ECL more widely. Immunosensors, which combined the high sensitive sensor technology with specific immunoreaction, are biosensors based on specific antigen-antibody interactions. Combining of both, nanoparticles-based electrochemical immunoassay technology has broad application prospects. In this dissertation, the water-soluble Cd Se quantum dots have been prepared by using L-cysteine as the stabilizer in aqueous phase. We construct a QDs-based ECL immunosensor for the detection of phenylethanolamine A residues. And the quantum dot is further modified with Si O2.The paper includes four aspects:In chapter 1, the significance and background knowledge of this dissertation have been introduced with the emphasis on the following aspects, the properties of nanoparticles-based electrochemiluminescence, funtamental principle of ECL immunoassay system and the application of nanoparticles-based ECL immunoassay.In chapter 2, the water-soluble quantum dots have been prepared by using L-cysteine as stabilizer. The optical properties of Cd Se have been studied by UV-Vis absorption and fluorescence spectroscopy, and its size properties have been characterized with highresolution transmission electron microscope and dynamic light scattering.In chapter 3, chitosan was utilized to immobilize quantum dots on the surface of glassy carbon electrode, and also provided platform for antigen. Horse radish peroxidase(HRP)was introduced by the specifical combination, which consumed H2O2, a pivotal coreactant.This was the first report for ultrasensitive detection phenethanolamine A using quantum dots-H2O2 and enzyme amplification system. It enriched the nanoparticles-based electrochemicalluminescence immunoassay applications.In chapter 4, quantum dots encapsulated with inert material Si O2, which can not onlyprotect the surface state of the quantum dot, but also provide a platform for ECL amplification. Cd Se@Si O2 was synthesized by reverse microemulsion, reducing the toxicity of quantum dots and making it safer to biological analysis.