Transforming growth factor Beta-releasing scaffolds for cartilage tissue engineering.

The maintenance of a critical threshold concentration of transforming growth factor beta (TGF-β) for a given period of time is crucial for the onset and maintenance of chondrogenesis. Thus, the development of scaffolds that provide temporal and/or spatial control of TGF-β bioavailability has appeal as a mechanism to induce the chondrogenesis of stem cells in vitro and in vivo for articular cartilage repair. In the past decade, many types of scaffolds have been designed to advance this goal: hydrogels based on polysaccharides, hyaluronic acid, and alginate; protein-based hydrogels such as fibrin, gelatin, and collagens; biopolymeric gels and synthetic polymers; and solid and hybrid composite (hydrogel/solid) scaffolds. In this study, we review the progress in developing strategies to deliver TGF-β from scaffolds with the aim of enhancing chondrogenesis. In the future, such scaffolds could prove critical for tissue engineering cartilage, both in vitro and in vivo.