Dual II-scheme nanosheet-like BiS/BiO/AgS heterostructures for ultrasensitive PEC aptasensing of aflatoxin B1 coupled with catalytic signal amplification by dendritic nanorod-like Au@Pd@Pt nanozyme.

As one of the most toxic chemical substances, aflatoxin B1 (AFB1) has a strong carcinogenic effect even at a trace level in human and animal, which severely threatens human health and even causes cancers. Therefore, ultrasensitive detection of AFB1 is of significant importance. For such analysis, dual II-scheme sheet-like BiS/BiO/AgS heterostructures were prepared by the in-situ growth method, which exhibited high separation efficiency for the electron-hole (e-h) pairs, prominent stability, and high photoactivity. Moreover, the dendritic nanorod-like Au@Pd@Pt (Au@Pd@Pt DNRs) nanozyme was homely synthesized, whose peroxidase-like activity was scrupulously investigated by catalytical oxidation of diaminobenzidine (DAB) in the presence of HO. Integration by the aptasensing strategy, a photoelectrochemical (PEC) "signal-on" aptasensor was prepared, which exhibited a broader linear range of 0.5 pg mL-100 ng mL with a lower limit of detection (LOD = 0.09 pg mL, S/N = 3). This work provides a feasible strategy to develop advanced PEC biosensors for actual analysis of environmental pollutants.