Niobium Carbide Mxene-Collagen Scaffolds For Diabetic Mandibular Bone Repair

This study investigates a novel niobium carbide MXene-collagen composite scaffold for diabetic mandibular defect repair, addressing hyperglycemia-driven inflammation and immune dysregulation. The "material-stem cell-immunity" strategy combines Nb₂C MXene nanosheets, dental pulp stem cells (DPSCs), and collagen to modulate macrophage polarization, suppress inflammation, and activate osteogenesis. Composite scaffolds with gradient Nb₂C MXene concentrations were fabricated and characterized for physicochemical properties and biocompatibility. DPSC microspheres loaded onto scaffolds were tested in vitro for paracrine regulation of macrophages and osteogenic differentiation. Animal models of diabetic mandibular defects validated efficacy, while molecular analyses elucidated mechanisms of Nb₂C MXene-mediated DPSC-macrophage crosstalk. The scaffolds exhibited enhanced osteoconductivity and degradation control. Nb₂C MXene promoted M2 macrophage polarization via IL-10/TGF-β secretion from DPSCs, reducing inflammation and fibrosis. Osteogenic markers (RUNX2, OCN) were upregulated, enhancing bone mineralization. In vivo, composites significantly improved defect repair with new bone formation, validated by histology and micro-CT. Mechanistically, Nb₂C MXene activated the PI3K/AKT pathway in DPSCs, synergizing with macrophage immunomodulation. The "material-stem cell-immunity" triad effectively overcomes diabetic bone repair barriers through immunoregulation and osteogenic activation. Nb₂C MXene serves as a multifunctional therapeutic agent, directing macrophage phenotypes and stem cell functions. This approach offers a promising strategy for refractory diabetic bone defects, with translational potential for inflammatory bone disorders.