A corn protein-based copper nanozyme with laccase-mimicking activity for bisphenol A detection and plastic food packaging degradation.

The use of low-cost and naturally derived proteins for constructing functional nanozymes is highly attractive for addressing challenges in food safety and managing post-consumer plastic packaging waste. This study reports a laccase-mimicking copper nanozyme engineered using zein, an abundant corn protein, as a cost-effective and sustainable scaffold. The zein-Cu nanozyme (Z-Cu NZ) is rapidly synthesized in aqueous solution and purified through acid-induced precipitation, leveraging the pH-dependent solubility of the zein scaffold. Z-Cu NZ demonstrates markedly enhanced catalytic activity and superior operational stability compared to natural laccase. In sensing applications, Z-Cu NZ enables sensitive colorimetric and smartphone-based detection of bisphenol A in both water and milk powder samples. Furthermore, by integrating the exceptional catalytic performance and enhanced interfacial adhesion derived from the hydrophobicity of the zein scaffold, Z-Cu NZ enables more efficient degradation of plastic food packaging than natural laccase, offering a promising approach to improve food safety and packaging sustainability.