Biomimetic Joint Paint forEfficient Cartilage Repair by Simultaneously Regulating Cartilage Degenerationand Regeneration in Pigs

Irregularpartial-thickness cartilage defect is a common pathogenesis of osteoarthritis(OA) with no available treatment in clinical practice. Currently, cartilagetissue engineering is only suitable for a limited area of full-thicknesscartilage defect. Here, we design a biomimetic joint paint for the intractablepartial-thickness cartilage defect repair. The joint paint, composed of abridging layer of chondroitin sulfate and a surface layer of gelatinmethacrylate with hyaluronic acid, can quickly and tightly adhere to thecartilage defect by light activation. Being treated by the joint paint, the groupof rabbit and pig models with partial-thickness cartilage defects showed arestoration of a smooth cartilage surface and the preservation of normal glycosaminoglycancontent, whereas the untreated control group exhibited serious progressive OAdevelopment. This paint treatment functions by prohibiting chondrocyteapoptosis, maintaining chondrocyte phenotype, and preserving the content ofglycosaminoglycan in the partial-thickness cartilage defects. These findingsillustrated that the biomimetic joint paint is an effective and revolutionarytherapeutics for the patients with non-curable partial-thickness cartilagedefects.