Photoelectrochemical biosensor for CEA detection based on SnS2-GR with multiple quenching effects of Au@CuS-GR

A novel signal on-off type photoelectrochemical (PEC) biosensing system was designed for sensitive detection of carcinoembryonic antigen (CEA) based on tin disulfide nanosheets loaded on reduced graphene cxide (SnS 2 -GR) as the photoactive material and gold nanoparticles coated on reduced graphene oxide-functionalized copper sulfide ( [email protected] ) for signal amplification . It's the first time for SnS 2 -GR was exploited as a sensing matrix. Here, the photocurrent signals of SnS 2 were amplified attributed to the sensitization effect of graphene. As signal amplifier, [email protected] could quench the photocurrents of SnS 2 -GR not only through the p-n type semiconductor quenching effect as well as the steric hindrance effect, but also as peroxidase mimetics to catalyze the oxidation of 4-Chloro-1-naphthol (4-CN) to produce insoluble product on the electrode surface . Based on the multiple signal amplification ability of [email protected] , CEA was detected sensitively with a linear range from 0.1 pg mL −1 to 10 ng mL −1 and limit of detection down to 59.9 fg mL −1 (S/N = 3). Meanwhile, the PEC biosensor displayed excellent performance in the assay of human serum sample, showing good application prospects for various target analysis.