Silk-based materials: Emerging for tendon/tendon-bone regeneration

The tendon and tendon-bone interface injuries have long been an issue for clinical practice. Autologous or allogeneic transplantation has been found to be a good method for repairing injuries; however, many factors limit the application of autologous and allogeneic transplants, which urges researchers to find a new type of strategy for regeneration. Silk fibroin (SF) scaffolds serve as promising exogenous biomaterials for alternative tendon and bone regeneration strategies. As its excellent biocompatibility, satisfactory mechanical properties, controllable biodegradability, and structural tunability, SF scaffolds have shown great potential in tendon and tendon-bone interface regeneration with carefully designed structures, bioactive ingredients, and functional surface modifications. However, several challenges remain, including improving the clinical translation and ensuring consistent quality of silk-based materials. This review mainly focuses on the theoretical foundations that make silk-based materials suitable for tendon and tendon-bone interface regeneration. Specifically, it covers silk-based particles, silk-based films, silk-based hydrogels, silk-based sponges, and silk-based polymeric fibers. It also summarizes their material design, biological interactions, regenerative applications, and clinical potential.