Abstract: The irregular porous structure, similar to human bone tissue, is more beneficial for bone ingrowth than the regular one. We proposed a new design method to create uniform and gradient irregular porous structures with porosities from 38 to 83% based on Voronoi tessellation. The models were fabricated using selective laser sintering, and micro-CT was used to assess their morphological features. Mechanical and fluid flow properties were evaluated through experiments and computational fluid dynamics simulations. Micro-CT scans confirmed that 3D printing can produce high-quality irregular structures. The Graded Irregular (GI) structure showed clear advantages in mechanical properties by reducing stress shielding and improving hydrodynamic performance with higher fluid flow velocity and lower permeability compared to the Uniform Irregular (UI) structure. Additionally, in vitro cell experiments indicated that the GI structure was better than the UI structure in promoting osteogenic differentiation, while in vivo animal studies showed that the GI structure was superior in terms of the ratio of Bone Volume to Total Volume (BV/TV) and Trabecular Number (Tb.N). Thus, the GI structure has greater application potential in bone tissue engineering.

Key words: Irregular structure, Mechanical properties, Fluid dynamic, Bone growth