Development of a Selective Electrochemical Biosensor for Bisphenol a Based on Target-Induced Chain Release Involving Methylene Blue Release

Abstract

A selective, sensitive electrochemical biosensor is reported to determine bisphenol A (2,2-bis(4-hydroxyphenyl) propane, BPA) based on target-induced chain release. A gold electrode was premodified with dendritic gold nanoparticles (AuNPs) by direct electrochemical deposition to increase the active surface area of the electrode to immobilize hydrosulfonyl group-containing capture DNA (C-DNA). C-DNA was hybridized with a BPA-specific aptamer (T-DNA) to form a double helical structure. After the embedding of methylene blue (MB), this structure emitted measurable electrochemical signals. BPA specifically binds to T-DNA to form a stable BPA G-tetrad structure, thereby inducing the release of the aptamer chain and the embedded MB from the surface into solution, resulting in the reduction of the current signal. The constructed electrochemical biosensor provided a linear response to BPA concentration from 1.0 × 10−9 M to 5.0 × 10−7 M with a detection limit of 9.8 × 10−10 M. This strategy also provided good selectivity for BPA compared to similar interferents.