Hyaluronic acid-doped bionic multilayer hydrogel scaffolds: Synergizing mechanical and lubrication properties for articular cartilage repair.

Joint cartilage's poor self-repair ability post-injury often leads to dysfunction and osteoarthritis. To tackle this issue, we developed a hyaluronic acid-doped bionic multilayer hydrogel scaffold (SCL), inspired by bionic design principles. The base layer (S layer) of the scaffold integrates polylactide with a silane coupling agent, KH570-modified nano hydroxyapatite, enhancing its mechanical strength. The middle layer (C layer), composed of polyethylene glycol diacrylate (PEGDA) and glycidyl methacrylate-modified hyaluronic acid, serves as a compression buffer. The top layer (L layer), made of PEGDA and 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC), provides superior surface lubrication. SCL scaffold exhibited tight interlayer bonding, good permeability (swelling ratio reduced from 7.0 to 3.7), degradability (23.1 % degradation within 8 weeks), and an excellent hydration lubrication effect (interfacial friction coefficient under hydrated conditions was 0.05). Cell experiments show that BMSCs grow well in each layer, with enhanced biological activity promoting osteogenic and chondrogenic differentiation. In a rabbit femoral defect model, the scaffold shows excellent bone repair ability, reducing surface roughness by 87.2 % for smooth regenerated cartilage. This study advances hydrogel composite scaffolds in cartilage tissue engineering and offers a bionics-inspired strategy for hydrogel implant materials.