New immunoprobes based on bovine serum albumin-stabilized copper nanoclusters with triple signal amplification for ultrasensitive electrochemical immunosensing for tumor marker

Abstract

In this work, a novel strategy for immunoprobe with triple signal amplification was developed, which bovine serum albumin-stabilized copper nanoclusters (BSA-CuNCs) and the labeled antibody were co-immobilized directly on platinum nanoparticles (PtNPs). The triple current signal amplification of the immunoprobe behaved: (1) BSA-CuNCs, realizing the enrichment of copper, served as redox species with current signal at 0.06V. (2) PtNPs as carriers were employed to immobilize the labeled antibody and enrich BSA-CuNCs. (3) The current response was further enhanced by BSA-CuNCs to accelerate the catalytic oxidation of ascorbic acid. Prostate specific antigen (PSA) was used as a model analyte to study the performance of the immunoprobe and electrochemical immunosensor. The immunosensor was fabricated as follows: anti-PSA was immobilized directly on gold nanoparticles, which were electrochemically deposited on glass carbon electrode; after immune-adsorbing PSA, the as-prepared immunoprobes were immunoadsorbed. Under the optimal conditions, the proposed immunosensor performed a wide linear range from 0.5pgmL−1 to 100ngmL−1 and an ultralow limit of detection with 145.69fgmL−1 (S/N=3). In the assay of clinical serum samples, the results of the proposed immunosensor showed good consistent with those of enzyme-linked immunosorbent assay, indicating the immunosensor is promising in clinical diagnosis. This strategy will be of guiding significance to fabricating new immunoprobes with catalytic activity and signal amplification ability.