Scaffolds for bone tissue engineering are porous structures that serve as support for cellular growth and, therefore, new tissue formation. The present work assessed the influence of the porous architecture of triply periodic minimal surface (TPMS) scaffolds on their macroscopic permeability behavior, combining numerical and experimental methods. The TPMS scaffolds considered were Schwartz D, Schwartz P, and Gyroid, which have been previously studied for bone tissue engineering, with 70% porosity. On the experimental side, these scaffolds were produced by MultiJet 3D printing and tested for fluid passage to calculate their permeability through Darcy’s Law. On the numerical side, finite element (FE) models of the scaffolds were simulated on ABAQUS^® for fluid passage under compression to assess potential fluid concentration spots. The outcomes revealed that the design of the unit cell had a noticeable effect on both calculated permeability and FE computed fluid flow velocity, regardless of the identical porosity, with the Gyroid scaffold having higher permeability and the Schwartz P a lower probability of fluid trapping. Schwartz D had the worst outcomes in both testing modalities, so these scaffolds would most likely be the last choice for promoting cell differentiation onto bone cells. Gyroid and Schwartz P would be up for selection depending on the application and targeted bone tissue.

The development of artificial bone substitutes that mimic the properties of bone and simultaneously promote the desired tissue regeneration is a current issue in bone tissue engineering research. An approach to create scaffolds with such characteristics is based on the combination of novel design and additive manufacturing processes. The objective of this work is to characterize the microstructural and the mechanical properties of scaffolds developed by coupling both topology optimization and a low temperature 3D printing process. The scaffold design was obtained using a topology optimization approach to maximize the permeability with constraints on the mechanical properties. This procedure was studied to be suitable for the fabrication of a cage prototype for tibial tuberosity advancement application, which is one of the most recent and promising techniques to treat cruciate ligament rupture in dogs. The microstructural and mechanical properties of the scaffolds manufactured by reacting α/β-tricalcium phosphate with diluted phosphoric acid were then assessed experimentally and the scaffolds strength reliability was determined. The results demonstrate that the low temperature 3D printing process is a reliable option to create synthetic scaffolds with tailored properties, and when coupled with topology optimization design it can be a powerful tool for the fabrication of patient-specific bone implants.