Injectable Hydrogels: In-Situ Tissue Engineering Strategies for Cartilage Repair and Regeneration

Repairing chondral defects remains challenging due to the avascular and acellular nature of cartilage. Advances in tissue engineering based on hydrogels offer significant potential for high-quality chondrogenesis, with injectable hydrogels emerging as a prominent area of research, because they meet the requirements for minimally invasive administration. This review provides an overview of recent progress in injectable hydrogels for cartilage repair and regeneration and summarizes the synthesis strategies. We specifically focused on key challenges including gelation techniques, robust bioadhesion, and bioactive functionalization, which are primary obstacles to achieving superior chondral repair in recent studies. By exploring current strategies to address these challenges and their underlying mechanism, we aim to inspire continuous advancements in promoting the application of injectable hydrogels for cartilage regeneration.