Multi-crosslinked hydrogels composed of hyaluronic acid, silk fibroin and chitosan nanoparticles with capacity of bioactive molecule delivery and degradation tolerance for cartilage tissue engineering

Polymer hydrogels intended for cartilage repair applications need to be mechanically competent and degradation-endurable. Combining these essential properties jointly into the natural polymer hydrogels is an ongoing challenge. Here, a new type of multi-crosslinked composite hydrogel with enhanced mechanical and degradation-resistant properties has been developed using thiolated hyaluronic acid (THA), silk fibroin (SF), and thiolated chitosan (TCH) nanoparticles (NPs). In addition, kartogenin is loaded into TCH NPs, and meanwhile, platelet-derived growth factor-BB is incorporated into the gel matrix in combination with fucoidan for bestowing collaborative biofunctions upon the composite hydrogels. The optimally achieved THA/SF/TCH hydrogels exhibit strong, elastic, and tough characteristics and enhanced degradation tolerance. The THA/SF/TCH hydrogels also show a confirmative ability to stimulate the migration of bone marrow mesenchymal stem cells and induce their chondrogenic differentiation. These results suggest that these composite gels have promising potential as an injective material for endogenous articular cartilage repair and regeneration.