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

## TL;DR

This study shows that 3D-printed Gyroid-shaped titanium scaffolds better support blood vessel growth and new bone formation in rabbit jaw defects compared to cube-shaped scaffolds.

## Contribution

The novelty lies in demonstrating the superior angiogenic and osteogenic potential of Gyroid-shaped TC4 scaffolds over conventional cube-shaped ones.

## Key findings

- Gyroid-shaped scaffolds induced greater angiogenesis and new bone formation compared to cube-shaped scaffolds.
- Higher expression of CD31, EMCN, HIF-1α, and VEGFA was observed in Gyroid-shaped scaffolds during early implantation.
- Imaging confirmed higher new bone formation in Gyroid-shaped scaffolds.

## Abstract

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.