An injectable cartilage-coating composite with long-term protection, effective lubrication and chondrocyte nourishment for osteoarthritis treatment.

The osteoarthritic (OA) environment within articular cartilage poses significant challenges, resulting in chondrocyte dysfunction and cartilage matrix degradation. While intra-articular injections of anti-inflammatory drugs, biomaterials, or bioactive agents have demonstrated some effectiveness, they primarily provide temporary relief from OA pain without arresting OA progression. This study presents an injectable cartilage-coating composite, comprising hyaluronic acid and decellularized cartilage matrix integrated with specific linker polymers. It enhances the material retention, protection, and lubrication on the cartilage surface, thereby providing an effective physical barrier against inflammatory factors and reducing the friction and shear force associated with OA joint movement. Moreover, the composite gradually releases nutrients, nourishing OA chondrocytes, aiding in the recovery of cellular function, promoting cartilage-specific matrix production, and mitigating OA progression in a rat model. Overall, this injectable cartilage-coating composite offers promising potential as an effective cell-free treatment for OA. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) in the articular cartilage leads to chondrocyte dysfunction and cartilage matrix degradation. This study introduces an intra-articular injectable composite material (HDC), composed of decellularized cartilage matrix (dECMs), hyaluronan (HA), and specially designed linker polymers to provide an effective cell-free OA treatment. The linker polymers bind HA and dECMs to form an integrated HDC structure with an enhanced degradation rate, potentially reducing the need for frequent injections and associated trauma. They also enable HDC to specifically coat the cartilage surface, forming a protective and lubricating layer that enhances long-term retention, acts as a barrier against inflammatory factors, and reduces joint movement friction. Furthermore, HDC nourishes OA chondrocytes through gradual nutrient release, aiding cellular function recovery, promoting cartilage-specific matrix production, and mitigating OA progression.