An Experimental Study on 3D-Printed Gyroid-Shaped TC4 Porous Scaffolds Guiding Angiogenesis and Osteogenesis in Bone Defect Areas

To investigate the ability of novel Gyroid-shaped titanium alloy (TC4) porous bioscaffolds to induce angiogenesis and osteogenesis in bone defect areas. This study employed selective laser melting (SLM) technology to fabricate Gyroid shaped and Cube-shaped TC4 porous bioscaffolds, using the commonly used cube shape as a control. The unit cell size was 4 mm, with a wall thickness or rod diameter of 300 μm and a porosity of approximately 80%. These scaffolds were implanted into rabbit mandibular defect sites (10 mm × 7 mm × 5 mm) to evaluate the angiogenic and osteogenic potential of the Gyroid-shaped scaffold. Material characterization revealed that sandblasted and acid-etched (SLA) TC4 scaffolds met design specifications, exhibiting uniformly distributed micrometer-scale pores and enhanced surface hydrophilicity. Histological staining revealed that compared to the Cube-shaped scaffold, the Gyroid-shaped scaffold induced greater angiogenesis and new bone formation within the bone defect area. Both scaffolds demonstrated good biocompatibility. Western Blot and RT-qPCR results indicated that the Gyroid-shaped scaffold possessed superior angiogenesis potential (compared to the Cube-shaped scaffold). During the early implantation phase (1-2 weeks), Gyroid-shaped scaffolds exhibited higher expression of platelet-endothelial cell surface adhesion molecule 1 (CD31) and endothelial mucin (EMCN). Concurrently, vessel distribution within the scaffold showed spatial variation. Additionally, gene expression of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor A (VEGFA) was elevated in the early bone defect area. Imaging analysis confirmed successful implantation of both scaffolds, with the Gyroid-shaped scaffold exhibiting a higher proportion of new bone formation. Consequently, the novel Gyroid-shaped TC4 porous bioscaffold demonstrates excellent potential for angiogenesis and osteogenesis, providing a reference for Gyroid-shaped scaffold-based bone defect repair.