Three-dimensional-printed strontium-incorporated β-TCP bioceramic triply periodic minimal surface scaffolds with enhanced angiogenic and osteogenic properties

Reconstructing bone defects remains a significant challenge in clinical practice, driving the urgent need for advanced artificial grafts that simultaneously promote vascularization and osteogenesis. Addressing the critical trade-off between achieving high porosity/strength and effective bioactivity at safe ion doses, we incorporated strontium (Sr) into β-tricalcium phosphate (β-TCP) scaffolds with a triply periodic minimal surface (TPMS) structure using digital light processing (DLP)-based three-dimensional (3D) printing. Systematically screening Sr concentrations (0-10 mol%), we identified 10 mol% as optimal, leveraging the synergy between the biomimetic TPMS architecture, providing exceptional mechanical strength (up to 1.44 MPa at 80% porosity) and facilitating cell recruitment and precision Sr-dosing to enhance bioactivity. <i>In vitro</i> assays revealed that the Sr-TCP scaffold dose-dependently stimulated osteogenic differentiation and mineralization in mouse osteoblastic cell line (MC3T3-E1) cells, while also significantly enhancing the angiogenic capacity in human umbilical vein endothelial cells (HUVECs). <i>In vivo</i> studies indicated that the scaffold demonstrated synergistic osteogenic and angiogenic effects in rat femoral condylar defects, leading to marked improvements in bone healing. Collectively, this study establishes a novel design paradigm combining biomimetic topology with optimized ionic doping, resolving key limitations of conventional grafts and advancing the development of safe, highly effective biomaterials for vascularized bone regeneration.