Applications of single-site iron nanozymes in biomedicine

With the vigorous development of nanozymes in recent years, single-site nanozymes (SSNs) with maximum atomic utilization of 100% have become a popular research frontier in various fields due to their tremendous advantages in both catalytic activity and selectivity. As for biomedicine, Fe-based SSNs not only have a high abundance of earth resources, but also share the normal Fe-Nx coordination structure, which is extremely similar to that of natural bioenzymes. Moreover, Fe ions play a crucial role in the Fenton response, exhibiting superior therapeutic effects. These unique advantages allow Fe-based SSNs to greatly shine in the biomedicine. In this review, we first describe the characterization and synthesis methods of atomic level sites. Then the biochemical action mechanism and in vivo pharmacokinetics of Fe-based SSNs is outlined. Following, we emphatically summarize the latest biomedical research and applications according to different application directions (including disease treatment, antibacterial wound disinfection, biosensing and oxidative stress cytoprotecting). Finally, a concise but directly summary and perspective is provided to outline the challenges for the future development of Fe-based SSNs for biomedical applications.