Polyelectrolyte-based electrochemiluminescence enhancement for Ru(bpy)₃²⁺ loaded by SiO₂ nanoparticle carrier and its high sensitive immunoassay.

In this paper the strong electrochemiluminescence (ECL) nanoparticles have been prepared based on the anionic polyelectrolyte sodium polyacrylate (PAA)-ECL enhancement for Ru(bpy)3(2+), which were loaded by the carrier of SiO2 nanoparticle. There were two kinds of Ru(bpy)3(2+) for the as-prepared nanoparticles, the doped one and the exchanged one. The former was loaded inside the ECL nanoparticles by doping, in a form of ion-pair macromolecules PAA-Ru(bpy)3(2+). The corresponding ECL was enhanced about 2 times owing to the doping increase of Ru(bpy)3(2+). The latter was loaded on the PAA-doped Nafion membrane by ion exchange. The corresponding ECL was enhanced about 3 times owing to the ion-exchanging increase of Ru(bpy)3(2+). At the same time, ECL intensity of the doped-inside Ru(bpy)3(2+) was further enhanced 13 times because polyelectrolyte PAA in the doped membrane could obviously enhance electron transfer between the doped Ru(bpy)3(2+) and the working electrode. Furthermore, based on hydrophobic regions of the doped membrane antibody labeling could be easily realized by the as-prepared nanoparticles and then a high sensitive ECL immunoassay for HBsAg was developed. The linear range was between 1.0 and 100 pg mL(-1) (R(2)=0.9912). The detection limit could be as low as 0.11 pg mL(-1) (signal-to-noise ratio=3).