Cu₂O@Fe Prussian blue-integrated smartphone-assisted sensing strategy for hydroquinone and bisphenol A determination

Herein, we fabricated copper(I) oxide@iron Prussian blue (Cu₂O@Fe-PBA) nanozymes with enhanced peroxidase-, laccase-, and catalase-like activities, laying the foundation for establishing a colorimetric detection platform for hydroquinone (HQ) and bisphenol A (BPA). Specifically, taking advantage of the peroxidase-like activity of Cu₂O@Fe-PBA, specific detection of HQ was achieved based on the reductive characteristics of phenolic hydroxyl groups among phenolic isomers including catechol (CC), resorcinol (RC), and HQ. Additionally, leveraging the catalase- and laccase-like activities of Cu₂O@Fe-PBA, a dual-enzyme-driven cascade catalytic approach for signal amplification was developed to enable colorimetric identification of BPA. Interestingly, a portable smartphone platform was constructed by integrating paper chips, which means the measurement program captures colorimetric changes through the smartphone camera and obtains RGB values, successfully achieving point-of-care testing (POCT) for HQ and BPA. This work guided the synthesis of nanozymes with multiple enzymatic activities, and introduced a novel design strategy for on-site monitoring of environmental pollutants.