Application Of Gold Nanoparticles In Immunoassay And Synthesis Of Magnetic Nanoparticles

Nanoparticles have become one of the quite popular problem in materials reseach field, owing to their many peculiar properties and their great high technology applied prospect. Immunoassays is significant to life science and medicine. They have direct effect on the accuracy of result. According to the nature of a label and the measurement, Immunoassay can be classified as enzyme immunoassay, fluorescent immunoassay, electrochemical metalloimmunoassay, chemiluminescent immunoassay, bioluminescent immunoassay and so on. In this work, I study the synthesis of the gold nanopartices and the magnetic nanopartices, make systematic researched in the aspect of electrochemical metalloimmunoassay, and a new silver- enhanced colloidal gold electrochemical stripping detection strategy is presented, which should further improve the sensitivity of the metalloimmunoassay through the catalytic precipitation of silver on the gold nanoparticles. The assay' s sensitivity is competitive with colorimetric enzyme linked immuno-sorbent assay (ELISA) or with immunoassays based on fluorescent europium chelate labels, which should push the sensitivity of the metalloimmunoassay to the picomolar domain. It become a higy sensitive immunoassay.1. The recent progress of the synthesis of the nanopartices and the study of immunoassays are reviewed.2. In the paper, I use microemulsion and Massart hydrolysis to prepare the magnetic nanopartices, and use gold or SiO₂ coating the magnetization to obtain the core-shell composite powders. Study and discuss the synthesis conditions and character of the compositenanopartices.3. A novel, sensitive electrochemical immunoassay has been developed based on the precipitation of silver on colloidal gold labels which, after silver metal dissolution in an acidic solution, was indirectly determined by anodic stripping voltammetry (ASV) at a glassy-carbon electrode. The method was evaluated for a noncompetitive heterogeneous immunoassay of an immunoglobulin G (IgG) as a model. The influence of relevant experimental variables, including the reaction time of antigen with antibody, the dilution ratio of the colloidal gold-labeled antibody and the parameters of the anodic stripping operation, upon the peak current was examined and optimized. The anodic stripping peak current depended linearly on the IgG concentration over the range of 1.66 ng/mL to 27.25 ug/ml in a logarithmic plot. A detection limit as low as 1 ng/ml (i.e., 6x10-12M) human IgG was achieved.4. A novel, sensitive electrochemical immunoassay has been developed based on the precipitation of silver on colloidal gold labels which, after silver metal dissolution in an acidic solution, was indirectly determined by anodic stripping voltammetry (ASV) at a glassy-carbon electrode. The method was evaluated for a noncompetitive heterogeneous immunoassay of C3 as a model. The influence of relevant experimental variables, including the reaction time of antigen with antibody, the dilution ratio of the colloidal gold-labeled antibody and the parameters of the anodic stripping operation, upon the peak current was examined and optimized. The anodic stripping peak current depended linearly on the logarithm of C3 concentration over the range of 7.2ng/mL to 7.33(j.g/mL and a detection limit as low as 7ng/mL is achieved. The anodic stripping immunoassay is applied to the determination of C3...