Injectable chitosan-oxidized hydroxypropyl cellulose/bioactive glass hydrogel composite for cartilage repair: Characterization, in vitro and in vivo assessment

Articular cartilage repair remains a major clinical challenge, necessitating the development of advanced biomaterials such as hydrogels. In this study, we developed an injectable hydrogel scaffold reinforced with 9 wt% of 58S bioactive glass fibers containing 5 wt% CuO (58S-5wt.% CuO). The hydrogel matrix was composed of chitosan (CH) and oxidized hydroxypropyl cellulose (OHPC), crosslinked through dynamic covalent bonding. Comprehensive physicochemical and biological characterizations were performed. Dynamic mechanical analysis revealed a significant enhancement in mechanical strength, with a storage modulus (G′) of 629 Pa for the CH-OHPC/9BG scaffold, compared to 378.6 Pa for the unreinforced CH-OHPC hydrogel. The scaffolds exhibited excellent self-healing ability and cytocompatibility, as evidenced by MTT assays. Furthermore, bone marrow-derived mesenchymal stem cells (BMSCs) demonstrated enhanced proliferation and chondrogenic differentiation when cultured on CH-OHPC/9BG scaffolds in chondrogenic induction medium. In vivo implantation in a rat knee defect model showed superior cartilage regeneration in the CH-OHPC/9BG group after two weeks. Overall, these findings indicate that the CH-OHPC/9BG hydrogel scaffold holds strong promise as a candidate for cartilage tissue engineering applications.