Biological response of 3D-printed -tricalcium phosphate bioceramic scaffolds with the hollow tube structure

It is a large clinical challenge to repair critical-size bone defects, and vascularization in the early stage is of vital importance in bone regeneration. In recent years, 3D-printed bioceramic is a kind of common bioactive scaffold for repairing bone defects. However, conventional 3D-printed bioceramic scaffolds consist of stacked solid struts with low porosity, which limits the ability of angiogenesis and bone regeneration. The hollow tube structure can induce endothelial cells to build the vascular system. In this study, beta-tricalcium phosphate (beta-TCP) bioceramic scaffolds containing the hollow tube structure were prepared with digital light processing-based 3D printing strategy. The physicochemical properties and osteogenic activities of prepared scaffolds could be precisely controlled by adjusting the parameters of hollow tubes. Compared with solid bioceramic scaffolds, such scaffolds could significantly improve the proliferation and attachment activity of rabbit bone mesenchymal stem cells in vitro, and facilitate early angiogenesis and subsequent osteogenesis in vivo. Therefore, beta-TCP bioceramic scaffolds with the hollow tube structure possess great potential application for the treatment of critical-size bone defects.