NIR-driven polydopamine based nanoenzymes as ROS scavengers to suppress osteoarthritis progression

The excessive reactive oxygen species (ROS) is always associated with the degradation of cartilage matrix during osteoarthritis (OA). The development of novel nanoenzymes with excellent ROS scavenging ability and biosafety shows great potentials for improving OA treatment. Herein a novel functional polydopamine (P) loading with ultrasmall Pt and Cu nanoparticles (P@Pt@Cu) was developed to act as nanoenzymes to scavenge ROS for OA treatment, wherein the excellent catalytic activities of Pt and Cu were employed. Results showed that P@Pt@Cu simultaneously presented obvious enzyme-mimicking properties like superoxide dismutase, catalase, and glutathione peroxidase, leading to excellent antioxidant and anti-inflammatory activities in H2O2 stimulated chondrocytes and OA joints with low cytotoxicity, leading to significant alleviation of OA progression. Besides, near infrared stimulation strengthened the antioxidant and anti-inflammation ability of P@Pt@Cu, resulting in the most prominent therapeutic effects. The proposed polydopamine-based nanoenzymes inspired a novel therapeutic strategy for OA therapy in clinic.