Bone scaffolds are porous materials used in therapies for healing large or nonhealing bone defects. To support bone regeneration, a bone scaffold acts as a carrier for biological molecules and cells, whose behavior is governed by local transport phenomena and deformations of the three-dimensional porous structure. Nevertheless, the structural parameters that guide the cells towards optimal osteogenic conditions are still to be determined. To assist the identification and quantification of the parameters that provide optimal osteogenic conditions, this work aimed at controlling the geometrical and mechanical properties throughout a bone scaffold with a given external shape via an appropriate design of its internal architecture.

In the first part of this study, a generic computer-aided design (CAD) framework was proposed for designing bone scaffolds. The framework incorporated costeffective methods for the determination and control of geometrical and mechanical parameters based on periodic unit cells. The methods were compared against experimental data obtained for regular Ti6Al4V bone scaffolds, produced by Selective Laser Melting (SLM). Only a partial validation of the methods was possible, as they did not account for the relatively large intrinsic scaffold roughness. The roughness caused the mechanical models to overestimate the mechanical stiffness, whereas a good agreement was found for the geometrical parameters.

In the second part, bone scaffolds consisting of a network of slender beams were modeled using cost-effective albeit approximate beam models. For particular beam geometries and load conditions, insightful analytical expressions were derived for the surface strain distribution in function of the deformation mechanisms and the geometry of the beams. The expressions were applied in a procedure for maximizing the percentage of surface area exhibiting strains within a particular window, by adjusting the profile and dimensions of each beam for a given network geometry and physiological loading conditions. This procedure was used to improve the specific strength of regular bone scaffolds, as well as their osteogenic capacity, assuming that particular strain windows can have a stimulatory effect on cells seeded in the scaffold.