A Comprehensive Review of Metal-Based Nanozymes for ROS Scavenging and Therapeutic Applications in Osteoarthritis

Reactive oxygen species (ROS) play a crucial role in the occurrence and development of osteoarthritis (OA). The homeostasis of the joint environment becomes imbalanced when joints are affected by various adverse factors, such as long-term excessive wear, trauma, and aging. Excessive accumulation of ROS in the joint can cause a series of harmful chain reactions and affect the normal function of joints. Traditional drugs are mainly used to relieve patient symptoms and cannot repair damaged cartilage or prevent the destruction process. Long-term use of these drugs may cause side effects. With the vigorous development of modern medicine and materials science, metal-based nanozymes have shown therapeutic effects in clearing ROS, anti-inflammatory effects, and promoting cartilage protection due to their unique physical and chemical properties. Metal-based nanozymes demonstrate the advantages of simulating various natural enzyme activities, multitarget synergy, and reshaping the microenvironment of joint lesions. In this review, the dynamic balance mechanism of chondrocytes in joints was introduced, followed by ROS-driven OA cartilage and synovial injury. Emphasis was placed on the application of metal-based nanozymes including Cu, Mn, Fe, Ce, Au, Pt, PB, and Ag in the field of OA. Finally, preclinical safety evaluation was discussed, confirming the efficacy of some metal-based nanozymes in the joint. We hope to provide useful references for future research and promote the progress of nanomedicine in the field of OA.