Nanozymes: a dual approach to bacterial colorimetric and luminescent detection and to bacterial pathogen killing

Rapid identification of bacteria is a critical analytical procedure vital for laboratory diagnostics of infections and for monitoring technological processes in pharmaceuticals, the food industry, and agricultural biotechnology. Biosensor systems based on artificial enzyme mimics, nanozymes, offer a promising alternative to conventional bacterial detection methods due to their high sensitivity, rapid response times, and potential for miniaturization. Nanozymes possess advantageous properties such as high stability, tunable catalytic activity, and surface functionalization capabilities, enabling the development of portable point-of-care (POC) platforms for real-time, on-site pathogen detection. This review systematically examines advances in optical (colorimetric and luminescent) nanozyme-based sensors for bacterial detection. A significant advantage of these sensors is that their output signals can be easily observed with naked eye, requiring no complex equipment. As antibiotic-resistant bacteria become more widespread, the review emphasizes nanozyme-based theranostic strategies that integrate optical pathogen diagnostics with diverse therapeutic modalities, including photothermal therapy, photodynamic therapy, chemodynamic therapy, and biofilm matrix degradation. Challenges impeding the commercialization of nanozyme-based theranostic agents are discussed, along with potential solutions to address these barriers. The review underscores the need to resolve challenging problems to facilitate the translation of nanozyme-based theranostic agents into practical clinical and industrial applications.