Multifunctional injectable GelMA hydrogel incorporating Icariin-loaded Mesoporous silica nanoparticles to promote osseointegration

The repair of bone defects faces the dual challenges of limited autograft availability and the single functionality of artificial materials. Consequently, the development of new biomaterials with mechanical adaptability, controlled drug release, and osteoinductive properties has become a major research focus in bone tissue engineering. In this study, we designed an injectable, photocrosslinkable hydrogel by incorporating icariin (ICA)-loaded mesoporous silica nanoparticles (MSNs) into gelatin methacryloyl (GelMA). The MSNs increased the compressive modulus by 1.5-fold and enabled pH-responsive ICA release. <i>In vitro</i> experiments demonstrated that the composite hydrogel enhanced rat bone marrow mesenchymal stem cell (rBMSC) proliferation and exhibited superior osteogenic differentiation capacity. <i>In vivo</i>, micro-CT analysis revealed a significantly higher bone volume fraction (BV/TV) in rat calvarial defects at 12 weeks, while histological examination confirmed the formation of mature trabecular bone. Overall, this MSN-mediated spatiotemporal delivery system effectively integrates immunomodulation with osteogenesis, providing a promising strategy for non-load-bearing osseointegration.