Fabrication of Graphene-Quantum Dots Composites for Sensitive Electrogenerated Chemiluminescence Immunosensing

A novel strategy is reported for the fabrication of poly(diallyldimethylammonium chloride) (PDDA)-protected graphene-CdSe (P-GR-CdSe) composites. An advanced electrogenerated chemiluminescence (ECL) immunosensor is proposed for the sensitive detection of human IgG (HIgG) by using the as-prepared P-GR-CdSe composites. The P-GR-CdSe composite film shows high ECL intensity, good electronic conductivity, fast response, and satisfactory stability, all of which holds great promise for the fabrication of ECL biosensors with improved sensitivity. After two successive steps of amplification via the conjugation of PDDA and gold nanoparticles (GNPs) in the film, high ECL intensity is observed. The ECL immunosensor has an extremely sensitive response to HIgG in a linear range of 0.02-2000 pg mL(-1) with a detection limit of 0.005 pg mL(-1). The proposed sensor exhibits high specificity, good reproducibility, and long-term stability, and may become a promising technique for protein detection.