Antimicrobial packaging films based on MOF nanozymes engineered via biomineralization and bimetallic hybridization for fruit preservation

The increasing prevalence of microbial contamination in the food industry has necessitated the development of advanced antimicrobial packaging materials. In this study, we developed a novel metal-organic framework (MOF)-derived nanozyme, CS/ZIF-67-Cu, synthesized through the biomimetic mineralization of chitosan (CS), followed by heterometallic hybridization. This structural configuration significantly enhanced the enzyme-mimetic activity and antimicrobial performance of the nanozymes. CS/ZIF-67-Cu efficiently generated reactive oxygen species (ROS) in situ and exhibited potent antimicrobial effects. By incorporating CS/ZIF-67-Cu into carboxymethyl cellulose (CMC), we engineered CMC@MOF composite films with enhanced antimicrobial efficacy, improved hydrophobicity, and superior UV–visible barrier properties. Preservation experiments on cherry tomatoes confirmed that the CMC@MOF films effectively inhibited microbial proliferation on the fruit surface, thereby significantly extending the shelf life. Because of its excellent biocompatibility and potent ROS-mediated antimicrobial efficacy, CS/ZIF-67-Cu has emerged as a highly efficient dual-functional nanozyme with oxidase- and peroxidase-like catalytic properties, demonstrating its potential for practical food preservation applications.