Colorimetric sensor array based on trimetallic MOF-derived Zn-Co-Cu nanozymes for discrimination of seven antioxidants.

Maintaining redox homeostasis relies heavily on antioxidants, and deviations in their normal levels are intimately linked to the onset of multiple diseases. Herein, a series of Zn-Co-Cu trimetallic MOF-derived nitrogen-doped carbon nanozymes (ZnCoCu-NCx) were synthesized via a core-shell MOF pyrolysis strategy. By tuning the Co/Cu ratio, a series of compositionally tunable nanozymes with distinct oxidase-like activities were obtained. Owing to the synergistic interaction among the three metallic constituents and the construction of bamboo-shaped N-doped carbon nanotube architectures, the as-prepared nanozymes displayed improved oxidase-mimetic performance and readily regulable catalytic response behaviors. Three representative nanozymes (ZnCoCu-NC2, ZnCoCu-NC3, and ZnCoCu-NC4) were selected to construct a three-element colorimetric sensor array, enabling accurate discrimination of seven antioxidants and their mixtures. The array was further validated for antioxidant analysis in human serum, providing a promising strategy for rapid detection of antioxidants in complex samples.