Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, PR China.
Industry Engineering Department, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, PR China.
Comput Methods Programs Biomed. 2022 Oct;225:107059. doi: 10.1016/j.cmpb.2022.107059. Epub 2022 Aug 6.
At present, there is a lack of efficient modeling methods for bionic artificial bone scaffolds, and the tissue fluid/nutrient mass transport characteristics of bone scaffolds has not been evaluated sufficiently. This study aims to explore an effective and efficient modeling method for biomimetic porous bone scaffolds for biological three-dimensional printing based on the imitation of the histomorphological characteristics of human vertebral cancellous bone. The fluid mass transport and mechanical characteristics of the porous scaffolds were evaluated and compared with those of a human cancellous bone,and the relationship between the geometric parameters (e.g., the size, number, shape of pores and porosity) and the performence of biomimetic porous bone scaffolds are revealed.
The bionic modeling design method proposed in this study considers the biological characteristics of vertebral cancellous tissue and performs imitation and design of vertebrae-like two-dimensional slices images.It then reconstructs the slices layer-by-layer to form porous scaffolds with a three-dimensional reconstruction method, similar to computed tomography image reconstruction. By controlling the design parameters, this method can easily realize the formation of plate-like (femoral cancellous bone-like) or rod-like (vertebral cancellous bone-like) porous scaffolds. The flow characterization of porous structures was performed using the computational fluid simulation method.
The flow characterization results showed that the permeability of the porous scaffolds and human bone was 10∼10m,and when the porosity of the porous scaffolds was higher than 70%, the permeability was higher than that of human vertebrae with a porosity of 82%. The maximum shear stress of the designed porous scaffolds and human vertebra were less than 0.8Mpa, which was conducive to cell adhesion, cell migration, and cell differentiation. The results of 3D printing and mechanical testing showed good printability and reflected the relationship between the mechanical properties and design parameters.
The design method proposed in this study has many controllable parameters, which can be adjusted to generate diversified functional porous structures to meet specific needs, increase the potential of bone scaffold design, and leave room for meeting the new requirements for bone scaffold characteristics in the future.
目前，仿生人工骨支架的建模方法效率不高，对骨支架的组织液/营养物质质量传输特性的评估也不够充分。本研究旨在探索一种基于人椎体松质骨组织形态学特征仿生的生物三维打印仿生多孔骨支架的有效建模方法，评估和比较多孔支架的流体质量传输和力学特性与松质骨的特性，并揭示几何参数（如孔的大小、数量、形状和孔隙率）与仿生多孔骨支架性能之间的关系。
本研究提出的仿生建模设计方法考虑了椎体松质组织的生物学特性，对类骨二维切片图像进行模仿和设计，然后采用类似于计算机断层扫描图像重建的三维重建方法对切片进行逐层重建，形成多孔支架。通过控制设计参数，可以轻松实现板状（股骨松质骨样）或棒状（椎体松质骨样）多孔支架的形成。采用计算流体模拟方法对多孔结构的流动特性进行了表征。
流动特性表征结果表明，多孔支架和人骨的渗透率为 10∼10m，当多孔支架的孔隙率高于 70%时，其渗透率高于孔隙率为 82%的人椎体。设计多孔支架和人椎体的最大剪切应力均小于 0.8Mpa，有利于细胞黏附、细胞迁移和细胞分化。3D 打印和力学测试结果表明具有良好的打印性能，并反映了力学性能与设计参数之间的关系。
本研究提出的设计方法具有许多可控制的参数，可以进行调整以生成多样化的功能多孔结构，以满足特定需求，增加骨支架设计的潜力，并为满足未来骨支架特性的新要求留出空间。
