PdPt bimetallic nanozyme-based colorimetric sensor for sensitive and label-free detection of gossypol

In this work, PdPt bimetallic nanoparticles with robust oxidase-like activity were synthesized, based on which a label-free, H₂O₂-free colorimetric platform was constructed for gossypol detection. The PdPt nanozyme activates dissolved oxygen to generate superoxide anions, efficiently catalyzing the oxidation of colorless TMB into blue oxTMB with a characteristic absorption at 652 nm. Gossypol, a reductive polyphenol, scavenges reactive oxygen species and reduces oxTMB, triggering a concentration-dependent absorbance decrease. Under optimized conditions, the sensor exhibited a linear response to gossypol in the range of 6.25-62.5 µM, with a detection limit of 1.92 µM, alongside strong anti-interference ability. Satisfactory recoveries of 98.01-109.56% were obtained in spiked egg yolk and milk samples, providing a simple cost-effective tool for rapid gossypol monitoring in food safety.