Photocatalytic Antibacterial Mechanism and Biotoxicity Trade-Off of Metal-Doped M-ZIF-8 (M=Co, Cu): Progress and Challenges

The proliferation of antibiotic resistance urgently demands the development of novel non-antibiotic-dependent antimicrobial strategies. Metal–organic framework material ZIF-8, with its tunable structure and excellent biocompatibility, shows great promise in the field of photocatalytic antibacterial applications. However, pure ZIF-8 suffers from limitations such as a narrow light absorption range and high carrier recombination rates. Doping ZIF-8 with transition metals such as cobalt or copper, herein denoted as M-ZIF-8 (M=Co, Cu), can significantly broaden its photoresponsive spectrum, promote reactive oxygen species (ROS) generation, and enable controlled metal ion release, thereby enhancing antimicrobial performance. Nevertheless, the release of metal ions also introduces potential biotoxicity concerns, limiting practical applications. This paper systematically reviews the trade-off between the photocatalytic antibacterial mechanism and biotoxicity of metal-doped M-ZIF-8 (M=Co, Cu), focusing on material design principles, antibacterial pathways, toxicity manifestations and mechanisms, as well as optimization strategies for “enhancing efficacy while reducing toxicity.” It further proposes future research challenges and directions in mechanism elucidation, smart material development, standardization, and industrialization to advance the safe and efficient application of these materials in medical and environmental fields.