A bioinspired hard-soft composites with strong interfacial bonding, high load-bearing and low friction for osteochondral repair

The development of osteochondral composites that simultaneously exhibit superior load-bearing performance and lubrication properties remains a significant challenge. In this investigation, a novel hard-soft composite material, which utilizes porous Si3N4 ceramics as a structural support and PVA-CBA (synthesis by condensation of polyvinyl alcohol and 4-formylbenzoic acid) hydrogels as a lubrication, was fabricated via impregnating the hydrogel into porous ceramics, namely Si3N4/PVA-CBA composites. It demonstrates strong interfacial bonding, comprising macro-micro scale mechanical interlocking and molecular scale chemical crosslinking. The developed material exhibits high mechanical strength ( 103.2 MPa and 1500 % larger than the corresponding value of porous Si3N4 ceramics), low friction and wear ( 0.21 under 10 N load and 10 Hz frequency), and favorable cell adhesion and proliferation. This provides an effective strategy for designing hard-soft composite material in the osteochondral repair field.