Solid substrate phosphorescent immunoassay based on bioconjugated nanoparticles

Room-temperature phosphorescent (RTP) immunoassay based on dye embedded pol yglutaraldehyde nanoparticles was described. Phosphorescent nanoparticles h ad been covalently linked to antibody to probe specifically antigen. The im munoassay was conducted by the typical procedure of sandwich type assay wit h polyamide membrane (PAM) sheet as solid substrate. In comparison with sin gle organic dye molecule, the nanoparticle probe was bright, and more stabl e against photobleaching. Moreover, the solid substrate at room temperature offered high signal and low background, which led to gain rather perfect s ensitivity. The concentration of immunoglobulin (IgG) in reaction with nano particles was optimized and the dependence of the phosphorescence intensity on the concentration of antigen was studied.