Nanozyme-based biosensors for intelligent food packaging

Increasing food safety and quality standards have made the development of rapid and efficient methods for monitoring food freshness, contamination, and harmful compounds essential. Nanozymes are a class of nanomaterials with enzyme-like activities that, due to their high stability over wide temperature and pH ranges, low production cost, and reusability, are considered promising alternatives to natural enzymes in biosensors. These nanomaterials exhibit peroxidase-, catalase-, oxidase-, and superoxide dismutase-like activities and can be employed in the design of single-enzyme and dual-enzyme sensing systems. Their practical application in intelligent food packaging enables real-time and non-destructive monitoring of the freshness of meat and aquatic products (with detection limits of 0.37–9.67 µM for hypoxanthine), fruits and vegetables (with detection limits of 0.6–1 µM for antioxidant content), as well as the detection of contaminants such as bisphenols, aflatoxins, metal salts, and pathogenic microorganisms. Nanozyme-based sensors, owing to their rapid response, high sensitivity, and ability to be integrated with portable devices, facilitate the transition of food monitoring from laboratory settings to storage and distribution cites. This comprehensive review examines the mechanisms of action of nanozyme-based sensors, their design principles, applications, and the challenges associated with their use in intelligent food packaging, and provides an outlook on their role in enhancing food safety and enabling rapid food quality monitoring.