Sandwich-type electrochemiluminescence immunosensor based on N-(aminobutyl)-N-ethylisoluminol labeling and gold nanoparticle amplification

A novel electrochemiluminescence (ECL) sandwich-type immunosensor for human immunoglobulin G (hIgG) on a gold nanoparticle modified electrode was developed by using W(aminobutyl)-N-ethylisoluminol (ABEI) labeling. The primary antibody, goat-anti-human IgG was first immobilized on a gold nanoparticle modified electrode, then the antigen (human IgG) and the ABEI-labeled second antibody was conjugated successively to form a sandwich-type immunocomplex. ECL was carried out with a double-step potential in carbonate buffer solution (CBS) containing 1.5 mM H2O2. The ECL intensity increased linearly with the concentration of hlgG over the range 5.0-100 ng/mL. The limit of detection was 1.68 ng/mL(S/N=3). The relative standard deviation was 3.79% at 60 ng/mL(n=9). The present immunosensor is simple and sensitive. It has been successfully applied to the detection of hlgG in human serums. (c) 2008 Elsevier B.V. All rights reserved.