Antioxidant Nanozymes: From Rational Design to Biomedical Applications.

Antioxidant nanozymes regulate reactive oxygen species homeostasis by mimicking the core catalytic functions of natural antioxidant enzymes, including superoxide dismutase-, catalase-, and glutathione peroxidase-like activities. The clinical translation of natural antioxidant enzymes has long been hampered by inherent limitations: short in vivo half-life, susceptibility to inactivation under physiological conditions, cumbersome purification processes, high production costs, non-negligible immunogenicity, and limited targeting capacity. In contrast, antioxidant nanozymes can overcome these bottlenecks with superior structural stability, tunable catalytic activity, low preparation cost, and flexible multifunctional modification. Guided by the catalytic mechanisms of natural enzymes, researchers have established rational design strategies for antioxidant nanozymes. To date, a diverse array of antioxidant nanozymes have been developed, with promising applications in multiple biomedical fields, including inflammatory diseases, ischemia-reperfusion injury, neurodegenerative disorders, and cancer adjuvant therapy. Notably, landmark clinical progress has been achieved: The catalytic nanocrystal suspension CNM-Au8, a therapeutic candidate for amyotrophic lateral sclerosis, has advanced to phase II clinical trials. This review systematically summarizes the core catalytic mechanisms of antioxidant nanozymes, clarifies the structure-activity relationships between rational material design and catalytic performance, reviews the latest advances in their biomedical applications, and dissects the key bottlenecks restricting preclinical research and clinical translation. It aims to provide rational design principles for researchers in this field, reduce empirical trial and error in material development, and provide guidance for the further optimization and clinical translation of antioxidant nanozymes.