Study Of Piezoelectric Quartz Crystal Sensors Based On The Enhancement Of Nanogold Particle

Inorganic nanoparticles have lots of special properties due to their surface effect, dimension effect, interface effect and quantum effect. Nanogold is one of such particles which have high surface ratio, strong absorptive ability and good biocompatibility, so it is widely used in the fields of molecular recongization, gene analysis and catalysis. Piezoelectric immunosensing technique incorporates the high sensitivity of piezoelectric quartz crystal microbalance and high specificity of antibody-antigen immunoreaction, presenting some outstanding advantages including desirable simplicity, rapid response, and so on, which make it showing an attractive future of potential applications in the biochemical diagnosis of clinical diseases. But the sensitivity of piezoelectric immunosensors still need to be improved in order to meet the requirement of morden analysis tecnique.This dissertation focuses on using nanogold particles to develop piezoelectric immunosensors with greated improved sensitivity. The main work is introcuced as follows:(1) The inorganic-organic nanocomposite of nanogold and chitosan, which have high biocompatibility, was synthesized in situ and used for the immobilization of antibodies. An amplified piezoelectric immunosensor for detection of normal human IgG was designed with this nanocomposite film. Comparing with self-assembling film of semi-cystamine, the inorganic-organic nanocomposite film could immobilize more antibodies with the activity of antibodis well retained. More over, the biosensor using nanogold-chitosan as immobilization matrix obtained larger response and better reproducibility. In the range of 10-150 ng/ml, it allowed the detection of IgG.(2). The determination of Human Thymidine Kinase (hTK) in human serum, which is a key indicator of cancers can give information for the diagnosis and treatment of the malign diseases. The protein A layer was first self-assembled onto the gold electrode surfaces of quartz crystals, the monoclonal antibodies were then orientedly immobilized through the specific binding between the Fc terminals of the antibodies and the self-assembled protein A. With this sensor, the affinity constant of antigen-antibody binding was estimated to be 1.85×106 L/mol according to the Scatchard's plotting method, which proved the high bioactivity of antibody. Finally, an amplified piezoelectric immunosensor was designed to determine the hTK in...