3D-Printed PLA/MgO/UCNPs composite scaffolds for immunomodulation and osteogenic bone repair

, cytocompatibility was evaluated using CCK-8 assays, live/dead staining, and immunofluorescence staining. The effects of the scaffolds on macrophage polarization and inflammatory factor expression were further analyzed. Their osteogenic differentiation potential was assessed by alkaline phosphatase (ALP) staining, Alizarin Red staining, and osteogenesis-related gene expression analysis. In addition, Micro-CT, hematoxylin and eosin (HE) staining, and Masson's trichrome staining were performed in a bone defect animal model to evaluate bone regeneration and tissue repair. The results showed that the composite scaffolds effectively improved the inflammatory microenvironment in the defect region, promoted macrophage polarization toward an anti-inflammatory phenotype, enhanced cellular osteogenic activity and mineralization, and facilitated new bone formation and tissue reconstruction. This study provides a theoretical basis and experimental evidence for the design and application of bone repair materials under inflammatory conditions.