A composite hydrogel loaded with the processed pyritum promotes bone repair via stimulate the osteogenic differentiation of BMSCs

Tissue engineering shows promise in repairing extensive bone defects. The promotion of proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by biological scaffolds has a significant impact on bone regeneration outcomes. In this study we used an injectable hydrogel, known as aminated mesoporous silica gel composite hydrogel (MSNs-NH 2 @GelMA), loaded with a natural drug, processed pyritum (PP), to promote healing of bone defects. The mechanical properties of the composite hydrogel were significantly superior to those of the blank hydrogel. In vitro experiments revealed that the composite hydrogel stimulated the osteogenic differentiation of BMSCs, and significantly increased the expression of type I collagen (Col 1), runt-related transcription factor 2 (Runx 2), alkaline phosphatase (ALP), osteocalcin (OCN). In vivo experiments showed that the composite hydrogel promoted the generation of new bones. These findings provide evidence that the composite hydrogel pyritum-loaded holds promise as a biomaterial for bone repair.