An injectable multi-functional composite bioactive hydrogel for bone regeneration via immunoregulatory and osteogenesis effects

Bone defects represent a prevalent and significant challenge in clinical practice. Given the inflammatory microenvironment at injury sites and the requirement for endogenous cell and tissue infiltration, there is an urgent need for an ideal biomaterial that can modulate inflammation and promote bone regeneration. We developed an innovative injectable hydrogel (CH@PUE&MSN) designed for immunomodulation and bone regeneration through in situ self-assembly, incorporating puerarin and chitosan with mesoporous silica nanoparticles. In vitro experiments demonstrated that this multifunctional injectable hydrogel promotes tissue cell regeneration, reduces inflammation, inhibits osteoclast formation, induces the migration and differentiation of bone marrow mesenchymal stem cells, and facilitates bone regeneration. Furthermore, we conducted an extensive in vivo evaluation using a bone defect model, employing advanced imaging and histological analyses. Our findings indicate that this multifunctional injectable hydrogel is a promising bioactive material for bone regeneration and presents a novel strategy for the clinical management of bone defects.