Polydopamine induced in-situ growth of Au nanoparticles on reduced graphene oxide as an efficient biosensing platform for ultrasensitive detection of bisphenol A

Bisphenol A (BPA) is one of the most prevalent environmental endocrine disrupting chemicals with potential estrogenic activity. Herein we report a facile electrochemical sensing strategy for ultrasensitive detection of BPA based on the hybrid of AuNPs decorated reduced graphene oxide (RGO). This Au@PDA-RGO hybrid was synthesized by in-situ growth of AuNPs induced by polydopamine (PDA) on RGO. Since PDA acts as a moderate reducing agent and an effective linker, AuNPs scatter well on RGO with controllable density, homogeneous size and uniform distribution. With the aid of chitosan (Chit), an electrochemical tyrosinase (Tyr) biosensor based on Au@PDA-RGO was constructed on glassy carbon electrode (Tyr/Au@PDA-RGO-Chit/GCE). This immobilization matrix possesses high conductivity, large active areas and a suitable biological microenvironment. As a result, the constructed Tyr biosensor exhibited good analytical performance for BPA with a high sensitivity of 0.2569 A M⁻¹, a wide linear range from 12.5 nM to 3.68 μM, and a low detection limit of 0.10 nM (S/N = 3). This method was also applied to detect BPA in plastic products, showing good agreement with the values detected by HPLC-MS/MS.