Bioinspired oxidase nanozymes for chlorpyrifos sensing and tetracyclines eliminating.

Oxidases play a crucial role in living systems and in vitro biotransformation. Nonetheless, the intrinsic fragility of natural oxidases confined their extensive utilization. Nanozymes with intrinsic oxidase-mimicking activity are emerging as potential alternatives to natural oxidases. Herein, inspired by the multicopper laccase, a representative member of oxidases, Ce-UiO-66 and Ce-MOF-808 with inherent multivalence were designed as biomimetic oxidase nanozymes for environmental catalysis. The multivalent cerium (Ce4+/Ce3+) within their frameworks can effectively mimic the multicopper (Cu2+/Cu+) active center of laccase, thus showing remarkable oxidase-like activity toward the oxidation of 2,4-dichlorophenol (2,4-DP) and 3,3',5,5'-tetramethylbenzidine (TMB). By comparison with natural oxidase, Ce-UiO-66 and Ce-MOF-808 demonstrated higher catalytic efficiency at the same mass concentration. They also exhibited satisfactory batch-to-batch, long-term storage, and recycling stability. Accordingly, Ce-UiO-66 and Ce-MOF-808 were practiced for colorimetric sensing of chlorpyrifos (CPs) and oxidative elimination of tetracyclines (TCs), indicating their potentiality for environmental remediation. This work implemented a metal active center biomimetic strategy for rational design of efficient oxidase nanozymes and broadened their practical applications, which would contribute to the development of nanozyme from both theoretical and practical aspects.