Nanozymes-based biosensors for food quality and safety

Nanozymes are nanomaterials, both metallic and non-metallic, that have the ability to catalyze biochemical reactions just as natural enzymes do. Since their discovery in 2007, nanozymes are exploited as nanoscale enzymatic mimics, which are now at the forefront for various biosensing applications. Compared with natural enzymes, nanozymes offer several advantages such as relatively higher stability, lower cost, easier modification, and inherently more efficient. Past research on the structure and catalytic principles of nanozymes has brought into focus various developments of nanozyme-based biosensors. Herein we introduce several typical nanozymes, primarily those belonging to the peroxidase and oxidase families. The enzyme mimicking mechanisms of these nanozymes are presented, which primarily result in colorimetric signals suitable for simple and easy biosensing. Emphasis is placed on nanozyme-based biosensors for detecting chemical contaminants, such as ions and pesticide residues, and biological contaminants, such as pathogens and biotoxins, that can compromise food quality and safety. In the future, more optimizations and improvements could be in the structure of nanozymes to enhance their catalysis ability and specificity. Overall, nanozymes possess great potential for biosensing in food and non-food applications.