Dynamic, Wet‐Adhesive Hydrogels for Enhanced Interface Healing in Cartilage Repair

Articular cartilage defects remain a major clinical challenge due to the tissue's limited self-repair capacity. Although numerous biomaterial-based strategies have been explored, achieving a stable and functional cartilage interface remains difficult. A critical barrier is the poor integration between grafts and native cartilage, leading to fibrocartilage formation, delamination, and repair failure. Current approaches show limited success due to inadequate wet adhesion, mechanical mismatch, and insufficient chemical bonding. Here, we report a dynamically adaptive wet-adhesive hydrogel composed of oxidized hyaluronic acid, quaternized chitosan, and silk fibroin (OHA/QCS/SF) for enhanced cartilage interface healing. The precursor exhibited rapid underwater spreading on hydrated substrates and displaced interfacial fluid in a fluid-covered assay. Fluorescence imaging further revealed wetting and infiltration into the PAAm hydrogel. Dynamic Schiff-base bonding between aldehyde groups in the hydrogel and amine-containing components at the cartilage interface further promoted wet adhesion, while the reversible network enabled self-healing under mechanical disturbance. In a rabbit cartilage defect model, the hydrogel loaded with synovial membrane-derived mesenchymal stem cells (SMSCs) improved defect filling, host-graft integration, and cartilage-like regeneration. This study provides a dynamic wet-adhesive hydrogel strategy for improving biomaterial-cartilage interface healing in fluid-rich joint environments.