Applications Of Quantum Dots (QDs) In Immunoassays

Quantum dots (QDs), as a class of nanomaterials with many unique properties, have been explored potential applications in biomolecular detection. In compassion with organic dyes, QDs offer such advantages as better fluorescence stabilities, narrow emission bandwidths and broad absorption spectra. As a marker applied in immune diagnose and immunoassay, it is a trend that QDs are instead of three traditional labeled technologies. It is important to research the quantificational immune detection by QDs. Herein novel immunoassays were established by QDs for their fluorescence properties.Influences of pH, buffers, temperature, save time, amino acids and proteins on fluorescence of QDs were studied. QDs linked with proteins by EDC. Competitive inhibition ELISA method of magnetic particles-SA and CdTe-SA to Biotin-HRP and dot immuno-percolation were used to detect the biologic activity of proteins after labeling. The results proved that the CdTe-ptotein composite could be applied in immunoassays as it had good dispersivity and good bioactivity. Utilizing the fluorescence properties of QDs, two novel immunoassays were established, which were the aggregation-based immunoassay and fluorescence quenching immunoassay. These two methods were used to detect Immunoglobulin (IgG) and HBsAg.The aggregation-based immunoassay for detecting Mouse IgG using QDs has been developed by using two matched antibodies. The Goat anti-Mouse IgG (GMIgG) labelled quantum dots was mixed with MIgG. After the immunoreaction between GMIgG and MIgG, the quantum dots aggregated to form a network, which could quench the fluorescence of themselves in the reaction system. The more MIgG was, the bigger the network was, and the fluorescence intensity of quantum dots decreased linearly. The concentration of MIgG could be detected by the measurement of QDs fluorescence intensity at 567nm, and the limit detecting concentration was 1.3nmol/L.QDs-GNPs fluorescence quenching immunoassay was developed through detecting the concentration of Hepatitis B Surface Antigen (HBsAg) in serum. To demonstrate its...