Highly sensitive and selective determination of bisphenol-A using peptide-modified gold electrode

Fast and accurate determination of bisphenol A (BPA) in varying matrices has become important in recent years. In this study, a cysteine-flanked heptapeptide sequence Cys-Lys-Ser-Leu-Glu-Asn-Ser-Tyr-Cys (CKSLENSYC), which is capable of recognizing BPA with high specificity, was isolated using a phage display technique. A novel electrochemical biosensor harnessing this affinity peptide as a BPA detection probe, was constructed and its performance was assessed. The formation of a self-assembled peptide monolayer on the gold electrode was confirmed by attenuated total reflection infrared spectroscopy (ATR-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Following the exploration of the optimum sensing condition, differential pulse voltammetry (DPV) was used to determine the varying concentrations of BPA in the solution. The developed sensor conveyed excellent performance in view of sensing speed, sensitivity and selectivity by detecting BPA in less than 5 min with a broad dynamic detection range of 1-5000 nM of BPA, despite the presence of several interfering species, such as phenolic compounds and inorganic ions.