3D-Printed PCL/SrHA@DFO Bone Tissue Engineering Scaffold with Bone Regeneration and Vascularization Function

The application of a three-dimensional (3D)-printed biological functional scaffold in the repair of bone defects is a promising strategy. In this study, strontium-containing hydroxyapatite (SrHA) powder was synthesized by the hydrothermal method, and then poly(ε-caprolactone) (PCL)/HA and PCL/SrHA composite scaffolds were prepared by the high-temperature melt extrusion 3D printing technology. The basic physical and chemical properties, in vitro biological properties, osteogenesis, and angiogenesis abilities of the scaffold were studied. The results showed that HA and SrHA were uniformly embedded in the composite scaffold, and the scaffold exhibited a 3D interconnected porous structure and rough microsurface. The in vitro release curve showed that Sr²⁺ and Ca²⁺ were continuously released from the PCL/SrHA scaffold. In order to verify the performance of the composite scaffold in bone regeneration, the proliferation and osteogenic differentiation of mouse embryonic osteoblasts (MC3T3E1) grown on the scaffold were evaluated. The experimental results showed that the incorporation of SrHA significantly promoted cell proliferation. Compared with the PCL/HA scaffold, the PCL/SrHA scaffold could better promote cell osteogenic differentiation. Deferoxamine (DFO) was loaded on the surface of the PCL/SrHA scaffold. By studying the proliferation, angiogenesis, and expression of osteogenesis and angiogenesis-related genes of human umbilical vein endothelial cells (HUVECs) on PCL/SrHA@DFO scaffold, it was verified that DFO had the ability to promote angiogenesis. It could induce angiogenesis in vitro in combination with Sr²⁺. Therefore, we believe that the composite scaffold has potential application prospects in the field of bone tissue engineering.