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

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-Ab) 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-Ab). When the appropriate antigen was recognized by this antibody, PSA-Ab, PSA, and PSA-Ab formed a sandwich-type immunocomplex that produced ECL in the presence of SO coreactant. Under optimal conditions, the ECL immunosensor showed a good linear range (0.0025-100.0 ng cm) and a low detection limit (1.0 pg cm). It was therefore demonstrated that the proposed strategy is a repeatable, stable, and potent method that can be expanded to detect other proteins. Graphical Abstract: [Figure not available: see fulltext.]. [ABSTRACT FROM AUTHOR]