OAlgMA/GelMA/CaCl2 multinetwork hydrogel scaffolds with enhanced mechanical properties for cartilage injury repair

Scheme 1. Multi-network GelMA/OAlgMA/Ca2 + hydrogel for enhanced cartilage repair. • Multi-network boosts mechanical strength. • Enhances BMSC chondrogenesis. • Suppresses inflammation effectively. • Superior cartilage repair in vivo . The incidence of cartilage injuries is high, and currently, there is no effective treatment method available. With the advancement of cartilage tissue engineering technology, natural materials can be modified to enhance their physicochemical properties while maintaining good biocompatibility. In this study, gelatin and sodium alginate were modified by grafting functional groups to synthesize Gela/OAlgMA/CaCl 2 multi-network composite hydrogel scaffolds. The physicochemical properties of the scaffolds, including pore size, swelling ratio, mechanical properties, and degradation behavior, were evaluated. The biocompatibility of the novel hydrogel was evaluated by conducting cell proliferation tests, live cell/dead cell staining and histocompatibility tests on bone marrow mesenchymal stem cells (BMSCs). Furthermore, the distal femoral cartilage defect model of New Zealand white rabbits was used to explore its application in cartilage tissue engineering. The results show that the composite scaffold has a good rigid network and multi-network system, which greatly improves the mechanical properties of the scaffold. Meanwhile, its excellent biocompatibility meets the requirements for cartilage tissue repair in tissue engineering materials. In conclusion, the multi-network hydrogel exhibits excellent mechanical strength and biological functionality. It can be considered an ideal tissue engineering scaffold for the regeneration and repair of articular cartilage defects.