Designing nanozymes for in vivo applications

Biocatalytic drugs, including natural and artificial enzymes that can accelerate biochemical reactions, are promising tools to address redox imbalances, metabolic disorders and immune dysregulations. However, these types of drugs suffer from uncontrolled activity, limited stability, heightened immunogenicity, lack of targeted action and adverse effects, which limit their clinical application. Preclinical results suggest that nanozymes, a new class of biocatalysts, could help overcome these challenges. In this Review, we discuss nanozymes for the regulation of reactive oxygen species in vivo. We first elucidate the fundamental mechanisms governing nanozyme-driven biocatalytic reactions in disease treatment. We then discuss the application of nanozymes in treating pathological disorders such as exogenous oxidative damage, inflammatory diseases, neurological disorders, tumours and bacterial infection. The design criteria for nanozymes to perform biocompatible and tightly regulated catalysis at targeted lesions are further highlighted. Finally, we explore the prospects, challenges and opportunities for clinical translation of nanozymes.