NIR-Responsive AuAgPt Plasmonic Nanozyme: Colorimetric/Photothermal Dual-Signal Sensing Array for Discriminating and Detecting Sulfur-Containing Compounds

Accurate discrimination and quantification of sulfur-containing compounds (SCCs) are essential for food safety. Herein, a near-infrared (NIR)-responsive AuAgPt ternary metallic plasmonic nanozyme is engineered, exploiting its broad NIR-I/II absorption to synergistically enhance peroxidase-like activity via plasmon-induced hot carriers, intermetallic electron transfer, and photothermal effects. This dual-signal amplification strategy enables the construction of a colorimetric/photothermal sensing array to discriminate five key SCCs (sodium sulfide, sodium thiosulfate, glutathione, dithiothreitol, cysteine) at micromolar sensitivities, combined with linear discriminant analysis. Validated in egg and milk matrices (recovery: 87.89-105.2%), this work establishes a multimetallic plasmonic nanozyme design to decouple catalytic enhancement mechanisms while delivering a robust platform for distinguishing structurally analogous analytes in complex samples.