Abstract

Cartilage regeneration, especially of the temporomandibular joint (TMJ) disc critical for chewing and speech, remains challenging. Key hurdles include its avascular, low-cell structure (impeding repair cell migration) and persistent post-injury compressive/shear stresses (damaging tissue and disrupting new formation). This study designed a sandwich composite hydrogel: GelMA/HAMA loaded with BMSCs, combined with a PVA-bacterial cellulose membrane carrying chondrocyte-derived exosomes. The membrane provides mechanical support and slowly releases exosomes to regulate BMSC proliferation/differentiation. Biomechanical analysis showed reduced stress concentration at perforation edges, protecting regeneration. In vitro experiments confirmed upregulated cartilage matrix genes (e.g., COL1A1, ACAN) in BMSCs. Implantation in a rabbit TMJ disc perforation model for eight weeks led to new cartilage-like tissue and successful repair. This system, optimizing mechanical microenvironment, regulating stem cell fate, and promoting matrix regeneration, offers a novel strategy for functional TMJ disc repair.