Au–Pt nanoparticle-based electrochemiluminescence immunoassay of a cancer biomarker using ZnO nanospheres coated with CdTe quantum dots as labels

Abstract

An easy-to-operate sandwich-type electrochemiluminescence (ECL) immunosensor was constructed on a glassy carbon electrode in this work. In order to fabricate a high-performance sensor, Au–Pt nanoparticles were electrodeposited onto the electrode surface, where they acted as the immunosensing platform, greatly improving the electronic transmission rate and increasing the amount of PSA primary antibody (PSA-Ab1) present. To increase the sensitivity of the sensor even further, stable CdTe/ZnO nanoparticles were synthesized, characterized by scanning electron microscopy, and then employed to label PSA secondary antibody (PSA-Ab2). When the appropriate antigen was recognized by this antibody, PSA-Ab1, PSA, and PSA-Ab2 formed a sandwich-type immunocomplex that produced ECL in the presence of S2O8 2− coreactant. Under optimal conditions, the ECL immunosensor showed a good linear range (0.0025–100.0 ng cm−3) and a low detection limit (1.0 pg cm−3). It was therefore demonstrated that the proposed strategy is a repeatable, stable, and potent method that can be expanded to detect other proteins. .