A dual-recognition paper-based sensor integrating a Ru/Co nanoparticle-single-atom catalytic interface for trace bisphenol A monitoring in complex matrices.

Although there has been relatively widespread exposure to bisphenol A (BPA) in the environment and consumer products, the sensitivity and selectivity of the current electrochemical sensors are still inadequate for accurate on-site monitoring of complex samples. To fill this deficiency, we have developed a flexible, single-use paper-based sensor that combines a nanoparticle-single-atom catalytic interface with an aptamer-molecularly imprinted polymer (Apt-MIP) dual recognition layer. The electrode material, Co@RuCoCNT, is prepared from a RuCo-ZIF precursor, has Ru/Co nanoparticles and atomically dispersed Co sites anchored onto nitrogen-doped hollow carbon nanotubes, and is then vacuum-filtered onto a patterned paper electrode. An Apt-MIP film electro-assembled on the Au-decorated surface creates shape-matched cavities for BPA. A detection limit of 23 fM and two linear ranges (0.1 pM-1.0 nM and 1.0 nM-1.0 μM) have been achieved. The recovery rates of real water and food samples are between 92.7 and 103%, and it shows good selectivity for BPA analogues. This paper presents an excellent design idea for a dual-recognition sensing platform and provides strong support for developing a high-performance detection tool for endocrine-disrupting substances.