PEC-EC dual-mode biosensing platform for PFOA assay based on competitive binding between HSA and PFOA or hemin

Abstract

Perfluorooctanoic acid (PFOA), a typical persistent per- and poly-fluoroalkyl substance (PFAS), may accumulate in the body and cause various human health problems. Herein, a novel photoelecrochemical (PEC)-electrochemical (EC) dual-mode biosensing platform has been developed for PFOA assay based on the competitive binding between amino-modified magnetic beads (MB)@human serum albumin (HSA) (MB@HSA) and hemin or PFOA. Through co-incubation of MB@HSA with PFOA and hemin, the MB@HSA-hemin-PFOA conjugates were obtained and collected by magnetic separation and then introduced onto the surface of the ZnCdS@ZnIn₂S₄-modified ITO electrode. After that, the PEC and EC measurements were carried out to achieve sensitive and accurate dual-mode detection of PFOA, based on the hemin-induced photocurrent enhancement of the ZnCdS@ZnIn₂S₄ heterojunction and the electrochemical properties of hemin. The developed PEC-EC dual-mode biosensing platform exhibited good selectivity, reproducibility and sensitivity with linear response ranges of 10 nM – 1 μM (PEC)/5 nM – 1 μM (EC) and detection limits of 8.71 nM (PEC)/1.46 nM (EC). The magnetic-assisted PEC-EC dual-mode sensing platform provides a new analytical route for the detection of PFOA in water samples and a new reference for environmental monitoring of PFOA.