Determination of human IgG by solid-substrate room-temperature phosphorescence immunoassay based on an antibody labeled with nanoparticles containing rhodamine 6G luminescent molecules.

Luminescent 50-nm silicon dioxide nanoparticles containing both types of rhodamine 6G (R; particles denoted R-SiO2) were synthesized by the sol-gel method. In the presence of Pb(Ac)2 as a heavy atom perturber the particle can emit the intense and stable room-temperature phosphorescence (RTP) signal of R on a polyamide membrane, with lambda(ex)max/ lambda(em)max=470/635 nm for R. Our research indicates that the specific immune reaction between goat-anti-human IgG antibody labeled with R-SiO2 and human IgG can be carried out quantitatively on a polyamide membrane, and the phosphorescence intensity was enhanced after the immunoreaction.