Injectable Hydrogels for the Repair and Regeneration of Articular Cartilage

Articular cartilage (AC) defects may be caused by injury or osteochondral pathology, which is a major risk factor for catastrophic degenerative arthritis. Currently, AC defects are a serious concern for patients because clinical treatments are not satisfactory. Owing to the limited self-healing ability of AC, the proliferation and chondrogenesis of seed cells are necessary for cartilage tissue regeneration. To treat AC defects, growth factors are required to regulate the behavior of seed cells for optimal therapeutic effects. Considering these issues, injectable hydrogels are suitable for both the repair and regeneration of AC because of their unique structural and functional features. After literature search and analysis, we introduced several gelation methods for injectable hydrogels. We then highlighted the biomedical applications of injectable hydrogels in the field of AC tissue engineering, with an emphasis on composite hydrogels, cell therapy, and carrier delivery. Finally, the achievements and challenges of injectable hydrogels for AC repair and regeneration were discussed based on previous studies. The summarized developments help to understand injectable hydrogels in the field of cartilage tissue engineering.