Femtomolar sensitivity of bisphenol A photoelectrochemical aptasensor induced by visible light-driven TiO2 nanoparticle-decorated nitrogen-doped graphene

Abstract

The development of superb visible-light-excited charge separation photoactive materials is of great significance for the establishment of biosensing platforms with excellent photoelectrochemical (PEC) performance. In this paper, we synthesized novel nanomaterials composed of titanium dioxide (TiO₂) nanoparticles and nitrogen-doped graphene (NG) by a facile one-pot thermal treatment method. Compared with pure TiO₂, the as-prepared TiO₂/NG displayed enhanced PEC performances ascribed to the introduction of NG, which effectively restrains the recombination of photoinduced electron–hole pairs, improves charge transfer, and extends photoresponse to visible light. Meanwhile, a novel PEC aptasensor was established for sensitive and selective detection of bisphenol A (BPA) with the assistance of BPA aptamer. In particular, femtomolar sensitivity of such a BPA PEC aptasensor can be achieved owing to the introduction of NG. Moreover, the proposed PEC aptasensor displayed a wide linear range from 1 fM to 10 nM and low detection limits of 0.3 fM. The biosensing platform has the features of fast operation, low cost, and good stability, which indicate that the as-prepared PEC sensor has great potential for applications in food monitoring and analysis.