Osseointegration of an innovative functionally gradient biomimetic scaffold based on Voronoi-Tessellation for the design of orthopaedic implants

The geometry and pore size of porous structures have a significant impact on osseointegration in orthopaedic implant design. This study introduced a new approach to designing biomimetic scaffolds using the Voronoi-Tessellation algorithm and additive manufacturing techniques. The results showed that the gradient structure designed by this method had decreasing thickness and pore size from top to bottom. Specimens printed using Selective Laser Sintering technology had higher structural thicknesses (20–57%) and lower porosities (24–42%) than CAD models, with an effective elastic modulus within the range of natural bone at 606–1522 MPa. Osteogenic differentiation experiments with bone mesenchymal stem cells in vitro showed stable cell proliferation and viability, as well as higher ALP activity and calcium nodule detection compared to the blank group. Animal experiments suggested that groups with larger pore sizes exhibited superior performance in promoting bone growth <i>in vivo</i> based on BV/TV and Tb.N measurement.

多孔结构的几何形态与孔径尺寸，对骨科植入物设计中的骨整合（osseointegration）效果具有显著影响。本研究采用沃罗诺伊镶嵌（Voronoi-Tessellation）算法与增材制造技术，提出了一种仿生支架设计的全新方法。研究结果表明，该方法制备的梯度结构呈现出从上至下厚度与孔径逐渐递减的特征。采用选择性激光烧结（Selective Laser Sintering）技术打印的试样，其结构厚度较计算机辅助设计（CAD）模型高出20%~57%，孔隙率则较CAD模型低24%~42%，且有效弹性模量处于天然骨的正常范围区间（606~1522 MPa）。针对骨髓间充质干细胞（bone mesenchymal stem cells）开展的体外成骨分化实验显示，与空白对照组相比，试样组的细胞增殖与活性状态更为稳定，且碱性磷酸酶（ALP）活性与钙结节检出量更高。动物实验结果表明，基于骨体积/组织体积（BV/TV）与骨小梁数（Tb.N）的检测指标，孔径更大的试样组在体内（in vivo）促进骨生长的性能更为优异。