Calcium-enriched mesoporous silica/PLGA scaffolds enhance bone repair in a rabbit femoral condylar defect model

Bone defects resulting from trauma, tumors, or infection continue to pose significant clinical challenges, particularly when the defect size exceeds the capacity for spontaneous healing. In this study, we fabricated two types of composite scaffolds-calcium carbonate/mesoporous silica/poly(lactic-co-glycolic acid) (CMP) and mesoporous silica/poly(lactic-co-glycolic acid) (MP)-using a single-emulsion solvent evaporation method. Both scaffolds exhibited interconnected porous structures and favorable morphology. In vitro assays demonstrated that CMP scaffolds more effectively promoted the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) compared to MP scaffolds. Furthermore, a rabbit femoral condylar defect model was established to assess the in vivo bone regeneration efficacy and biocompatibility. Micro-CT imaging, along with hematoxylin-eosin (HE), Masson's trichrome, and Movat's pentachrome staining, as well as serum biochemical analyses, consistently indicated that CMP scaffolds significantly enhanced new bone formation and defect repair relative to MP scaffolds. Both scaffold types showed excellent tissue compatibility and elicited no adverse systemic effects. These findings suggest that calcium-enriched mesoporous silica/PLGA scaffolds hold strong potential as clinical biomaterials for the treatment of bone defects.