Impacts of channel direction on bone tissue engineering in 3D-printed carbonate apatite scaffolds

• Main Authors: Koichiro Hayashi, Nao Kato, Masaki Kato, Kunio Ishikawa
• Format: Article
• Language: English
• Published: Elsevier 2021-06-01
• Series: Materials & Design
• Subjects: Tissue scaffold; 3D printer; Carbonate apatite; Tissue engineering; Regenerative medicine; Bone regeneration
• Online Access: http://www.sciencedirect.com/science/article/pii/S0264127521002380

Although the channel architecture of a scaffold is critical for bone regeneration, little is known for the channel direction. In this study, four types of carbonate apatite cylindrical scaffolds; scaffolds with biaxial channels (VH-scaffold), with uniaxial vertical channels (V-scaffold), with uniaxial horizontal channels (H-scaffold), and without channels (N-scaffold), were implanted in a rabbit femur defect for 4 and 12 weeks. Although the largest bone was formed 4 weeks post-implantation in the VH-scaffold, newly formed bone disappeared with the scaffold after 12 weeks. Thus, biaxial channels resulted in the rapid dissolution of the scaffold and were counterproductive in long-term bone regeneration. The V-scaffold that had channels connected to the periosteum was gradually resorbed throughout 12 weeks post-implantation. The percentage of mineralized bone in the V-scaffolds was equal to that in the natural bone. The resorption and bone percentage of H-scaffolds that had no channels connected to the periosteum were slower and lower, respectively, than those of V-scaffolds. Thus, channels should be connected to the periosteum to achieve smooth replacement by the new bone. In the N-scaffold, much less bone was formed inside the scaffold. This study contributes to providing a design guide for scaffold development in bone engineering.