Microenvironment engineering of MOFzymes for biomedical applications

Nanozymes, a type of nanomaterials with enzyme-like activity, have attracted growing attention in recent years due to their remarkable stability, tunable catalytic performance, multifunctionalities, and cost-effectiveness. Although significant progress has been made in the past decade, designing nanozymes with high selectivity, excellent catalytic activity, and new types of catalytic activities beyond oxidation-reduction reactions remains highly challenging. This is primarily due to the difficulties in fabricating well-defined nanozymes and precisely tailoring the microenvironment of catalytic sites at atomic level. Metal-organic frameworks (MOFs) with enzyme-mimicking activities (MOFzymes) offer several advantages over other nanozymes, including well-defined molecular structure and catalytic sites, high porosity, and large surface areas. MOFzymes mainly mimic various oxidoreductases, such as oxidase, peroxidase, catalase, superoxide dismutase, and glutathione peroxidase, making them suitable for various biomedical applications. In this article, the structures and properties of MOFzymes and the latest developments are thoroughly discussed. We particularly focus on the physical and chemical methods for microenvironment regulation of MOFzymes, and the working mechanisms. Furthermore, the applications of MOFzymes for biosensing, cancer therapy, antibacterial therapy, and anti-inflammatory therapy are described. Finally, we discuss the future opportunities and challenges of MOFzymes.