Design of bionic porous structure of bone scaffolds and analysis of fatigue and permeability characteristics.

Bone defects caused by trauma, malignant tumors, and other diseases are common symptoms in orthopedic surgery, and when they exceed the critical size of autologous repair, bone transplantation is required. Artificial bone scaffolds are an effective way to repair large bone defects. An ideal artificial bone scaffold should not only have appropriate mechanical properties and biocompatibility, but also have good osteoinductive properties. This paper proposed a bionic porous structure design method based on Voronoi diagram. In the design process, controlling pore morphology and pore size by adjusting irregularity and porosity. In addition, the designed scaffolds were fabricated through laser powder bed fusion (L-PBF) with Ti-6Al-4V powders. The mechanical characteristics were evaluated by static mechanical simulation with ABAQUS and fatigue tests, and the permeability characteristics were analyzed by fluid simulation with COMSOL and in vitro test. The research results showed that fatigue meet the natural bone implant criteria by controlling the porosity and irregularity. And the mathematical relationship between fatigue characteristics and porosity and irregularity parameters was fitted. It can effectively predict the fatigue characteristics of the scaffold and improve its application in natural bone. At the same time, the designed structure has closer permeability to the natural bone, and was conducive to cell proliferation. Therefore, the porous structure based on Voronoi diagram may have good application potential in the bionic design of bone implants.