Research On The Optics-Biosensor Based On New Quantum Dots And Amplification Technique

Since the nineteenth century, sensor technology has attracted widespread attention by many countries of the world. It is also an analytical method for test items at the molecular level. With the development of biochemical immobilization, immunoassay and microfabrication technology, the application of these technologies were broader in biological test. In this paper, the preparation of many new ECL functional nanomaterials was studied, and electrochemiluminescence biosensors were developed for the detection of protein such as antigen and thrombin.The followingthree main parts of this thesis can be studied:(1) We have prepared a novel PAMAM dendrimers-Au nanostructure with good bioactivity and electroconductibility, and used it to develop an amplified CdSe QDs ECL probe for ultrasensitive immunoassay. The unique nanostructure was used not only to assemble a large number of QDs signal labels, but also to accelerate the ECL reaction efficiency, which thus greatly amplify the QDs ECL signal. The PAMAM dendrimer was applied to construct an amplified immobilization platform for antibody molecules. Based on the specific sandwich immunoreactions, an ultrasensitive signal-on ECL immunosensor using the amplified QDs ECL signal probe was developed for IgG assay. The ECL signal is proportional to the concentration of IgG in the range of 0.1 fg·mL-1 to 500 fg·mL-1. The concentration of IgG detection limit by the calculation was 0.05 fg·mL-1.(2) We used a simple and effective method for preparing water-soluble CNCs with excellent fluorescence by applying CV. The CNCs has many unique advantages such as strong fluorescence, favourable biocompatibility, good stability and so on. On the one hand, the signal was amplified by the DNA cycling amplification technology. On the other hand, a large number of quantum dots were loaded to the magnetic microspheres by aptamer, thus the fluorescence intensity was further enhanced. This detection method is convenient and sensitive.It has great potential in the detection of biological molecules.(3) We synthesized a double stabilizer coated CdSe QDs and CdSe-NH2 QDs. We constructed an ultra-sensitive ECL biosensor based on ECL quenching of the double layer quantum dots by Au@Ag. In addition, we have prepared a novel AuG material and used it for modifying the electrode. It is not only make the electron transfer fast, but also can form a good film on the electrode. Thus the ECL signal is enhanced because of a larger surface area which can increase the diffusion of K2S2O8 in ECL process. This study on the ECL energy transfer between multi-layer quantum dots and Au@Ag laid a good foundation for bioanalysis, and it has a good prospect for clinical diagnosis in the future.