Near-infrared responsive nanozyme-carboxymethyl chitosan/chondroitin sulfate composite hydrogel: Multicomponent...

Bone defects currently face great challenges in clinical practice. Even traditional treatments, such as allogeneic bone grafting or autologous bone grafting, often have specific drawbacks. To address issues such as donor shortages and the need for secondary surgery in traditional surgical procedures, this study employed carboxymethyl chitosan and oxidized chondroitin sulfate as hydrogel matrices, preparing hydrogels through the Schiff base reaction. At the same time, Fe³⁺-taxifolin nanoparticles with dual functions of near-infrared photothermal effect and enzyme-like activity were encapsulated in the hydrogels. Experiments have shown that the addition of nanoparticles enhances the antibacterial and antioxidant activities of the hydrogels. In vitro experiments have shown that the hydrogels can promote osteoblast proliferation and upregulate the expression of osteogenesis-related proteins. In vivo studies have demonstrated that the hydrogels can promote bone healing through the BMP/Smad signaling pathway. This study provides new insights into the application of flavonoid natural products in regenerative medicine, bone tissue engineering, and other related fields, offering a simple and promising strategy for treating joint bone defects.