Nanozymes: bridging nanoscale characteristics and catalytic mechanisms for advanced biomedical applications.

Nanozymes-nanomaterials with intrinsic enzyme-like activity-have emerged as a transformative paradigm in biomedicine. Their catalytic proficiency is fundamentally dictated by unique nanoscale characteristics, particularly tuneable surface defects and geometric configurations. This review critically re-evaluates nanozyme catalytic mechanisms, precisely categorising them into reactive oxygen species (ROS)-generating pathways and electron-transfer processes. We highlight recent structural breakthroughs, emphasising the evolution from conventional nanoparticles to single-atom and dual-atom nanozymes (SANs/DANs) that exhibit unprecedented reaction kinetics. Furthermore, we synthesise their advanced applications across in vitro diagnostics, synergistic tumour therapy, antibacterial interventions, and regenerative medicine. Finally, we address current clinical translational bottlenecks and envision how artificial intelligence (AI)-guided rational design will shape the field's future. By bridging fundamental physical chemistry with clinical utility, this review provides a definitive mechanistic roadmap for deploying nanozymes in precision nanomedicine.