Injectable self-assembled GDF5-containing dipeptide hydrogels for enhanced tendon repair

Owing to the tissue characteristics of tendons with few blood vessels and cells, the regeneration and repair of injured tendons can present a considerable challenge, which considerably affects the motor function of limbs and leads to serious physical and mental pain, along with an economic burden on patients. Herein, we designed and fabricated a dipeptide hydrogel (DPH) using polypeptides P11-4 and P11-8. This hydrogel exhibited self-assembly characteristics and could be administered in vitro. To endow the hydrogel with differentiation and regeneration abilities, we added different concentrations of growth differentiation factor 5 (GDF5) to form GDF5@DPH. GDF5@DPH promoted the aggregation and differentiation of tendon stem/progenitor cells and promoted the regeneration and repair of tendon cells and collagen fibers in injured areas. In addition, GDF5@DPH inhibited inflammatory reactions in the injured area. Owing to its injectable properties, DPH can jointly inhibit adhesion and scar hyperplasia between tissues caused by endogenous inflammation and exogenous surgery and can provide a favorable internal environment for the regeneration and repair of the injured area. Overall, the GDF5@DPH system exhibits considerable promise as a novel approach to treating tendon injury.