BiS/BiOCl heterojunction-based photoelectrochemical aptasensor for ultrasensitive assay of fumonisin B via signal amplification with in situ grown AgS quantum dots.

Fumonisin B (FB) is a mycotoxin mainly found in corn, peanuts, and wheat crops, which affects human health. Based on bismuth sulfide/bismuth oxychloride (BiS/BiOCl) composite material, silver sulfide (AgS) was grown in situ as a quantum dot sensitization signal, and a photoelectrochemical (PEC) aptasensor was designed by layer upon layer modification to detect FB. BiS/BiOCl has a wide range of visible light absorption, stable chemical properties, and a simple synthesis method. In the construction process, L-ascorbic acid (AA) is selected to provide electrons and inhibit photogenerated electron-hole (e/h) recombination. Under the optimal experimental conditions, the detection range of the fabricated PEC aptasensor was 0.001 ~ 100 ng/mL, and the detection limit was 0.016 pg/mL. The prepared PEC aptasensor has high sensitivity, stability, and reproducibility. The combination of aptamer and PEC sensor provides a novel method for the application of PEC sensor in mycotoxin detection.