3D-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. In vitro 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). In vivo 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.