A novel photoelectrochemical sensing platform based on Fe₂O₃@Bi₂S₃ heterojunction for an enzymatic process and enzyme activity inhibition reaction

The visible-light photoactive heterostructures with effective carrier transformation and desirable material properties have caught more and more researchers’ attention in recent years. Herein, a photoelectrochemical sensing platform is constructed based on Fe₂O₃@Bi₂S₃ heterostructure for an enzymatic process and enzyme activity inhibition assay. In the proposal, the amount of Fe₂O₃ in Fe₂O₃@Bi₂S₃ sample was optimized firstly. Specifically, the photocurrent intensity of Fe₂O₃@Bi₂S₃ heterostructure is gradually enhanced with proper introduction of Fe₂O₃ . Moreover, the Fe₂O₃@Bi₂S₃ heterostructure is first used to design the sensing via hydrolytic reaction and enzyme activity inhibition reaction. When loaded on the substrate of Fe₂O₃@Bi₂S₃ with the help of gold nanoparticles, alkaline phosphatase (ALP) can hydrolyze L-ascorbic acid 2-phosphate trisodium salt to produce ascorbic acid in situ, consequently achieving the enzymatic process. In the second place, the constructed sensing is employed to detect the inhibitor of sodium fluoride for ALP, which is closely associated with enzyme activity and human health problems. The ingenious designed sensing presents an outstanding linearity for the detection of sodium fluoride, and the concentration varies from 0.01 to 1000 μM. The integration of heterostructure and photoelectrochemical technique demonstrates an innovative methodology for the assay of biological targets. Furthermore, the designed strategy can greatly enhance the analytical performance and thus provides a novel method for the high selective and sensitive detection of chemicals.