Solid Substrate Phosphorescent Immunoassay Based on Bioconjugated Nanoparticles

Room-temperature phosphorescent (RTP) immunoassay based on dye embedded polyglutaraldehyde nanoparticles was described. Phosphorescent nanoparticles had been covalently linked to antibody to probe specifically antigen. The immunoassay was conducted by the typical procedure of sandwich type assay with polyamide membrane (PAM) sheet as solid substrate. In comparison with single organic dye molecule, the nanoparticle probe was bright, and more stable against photobleaching. Moreover, the solid substrate at room temperature offered high signal and low background, which led to gain rather perfect sensitivity. The concentration of immunoglobulin (IgG) in reaction with nanoparticles was optimized and the dependence of the phosphorescence intensity on the concentration of antigen was studied.