Cartilage-targeted Au@Pt nanospheres with enhanced photothermal effect for promoting the recovery of osteoarthritis via ROS catalysis.

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the destruction of joint cartilage, changes in subchondral structures, and synovial inflammation. Employing a progressive research methodology, in this work we discerned that gold core-platinum shell (Au@Pt) nanospheres (MB) were capable of catalyzing ROS to inhibit chondrocyte apoptosis and collagen loss. Nevertheless, administration at high concentrations could trigger risks such as thrombosis and immune rejection. We observed that the targeting specificity of nanospheres towards chondrocytes was suboptimal, imposing constraints on their therapeutic efficacy. Through transplanting the peptide WYRGRL targeting chondrocytes onto nanospheres, we constructed TPMB. The findings indicated that the therapeutic concentration of TPMB was significantly lower than that of MBs, and no obvious systemic toxicity was present. In vivo studies verified that TPMB could reduce chondrocyte apoptosis and collagen degradation, while promoting collagen formation, contributing to the recovery of osteoarthritis. However, the effect of TPMB in promoting antigen deposition remains deficient. To further enhance its therapeutic outcome, we employed near-infrared light to activate the photothermal effect of TPMB for validating its therapeutic efficacy. The experimental results demonstrated that the promotion of collagen deposition by near-infrared activation of TPMB was significantly enhanced, attaining the optimal therapeutic effect. To sum up, TPMB based on the near-infrared enhancement effect effectively promotes the recovery of osteoarthritis by catalyzing the generation of ROS. As research in this area advances, the clinical potential of Au@Pt nanospheres is anticipated to expand, potentially providing new therapeutic avenues for patients with osteoarthritis.