An electrochemiluminescence immunosensor based on ABEI-GO-AgNPs as a double-amplified luminophore for the ultra-sensitive detection of prostate-specific antigen.

A sandwich electrochemiluminescence (ECL) immunosensor based on an N-(4-aminobutyl)-N-ethylisoluminol-graphene oxide-Ag nanoparticle (ABEI-GO-AgNPs) complex and cysteine silver nanowires (AgCysNWs) was prepared to detect prostate-specific antigen (PSA). Our results showed that an ECL signal probe, ABEI-GO-AgNPs, with an ultrahigh specific surface area, favorable catalytic properties, and electrical conductivity was prepared by a one-step synthesis method. ABEI-GO-AgNPs with good biocompatibility immobilized secondary antibody (Ab) via AgN bonds. Furthermore, AgCysNWs containing many -COOH groups were prepared and used to enrich primary antibody (Ab), which could be used as an affinity probe for the selective capture of PSA. Lastly, through layer-by-layer assembly, we established an ECL immunosensing platform for the sensitive detection of PSA. Under the optimized conditions, the designed ECL immunosensor showed promising sensitivity and selectivity for the detection of PSA in the linear range of 5.5 × 10-5.5 ng/mL, with a detection limit of 1.2 × 10 ng/mL. The constructed ECL sensing platform possessed good specificity, reproducibility, and stability and could detect PSA in actual human serum samples.