Mechanical anisotropy match of parameterized body-centered-cuboid scaffolds and trabecular bones

Abstract

The gold standard scaffold requires a perfect mechanical match between the scaffold and bones to create a suitable local mechanical microenvironment for bone repair; otherwise, the bone repair probably fails due to postoperative complications. Differently from the extensive biological evaluations of various scaffolds in the field of bone tissue engineering, this study first investigated the mechanical anisotropy match of a parameterized body-centered-cuboid (pBCC) scaffold to the trabecular bone. By varying two independent angle variables (θ and φ) of the scaffold, the mechanical anisotropy of the scaffold was fully characterized by the theory, experiment and finite element method, and its deformation patterns and failure features related to the two variables were clarified. In particular, the elastic modulus anisotropy ratios of the scaffold and the femoral-head trabecular bone were calculated to examine their match. The results demonstrated that the normalized elastic moduli and yield strengths of the scaffolds could be reliably predicted by the theory which was validated by the experiments and finite element analysis. Moreover, the deformation patterns and failure features of the scaffold were strongly influenced by the two angle variables which actually determined the scaffold height. Importantly, the scaffold could be designed to achieve a high anisotropy ratio to allow various elastic modulus anisotropy ratio match with trabecular bones from the femoral head, proximal tibia, lumbar spine, and mandibular condyle. In addition, the developed theory could be generalized to design suitable scaffolds made of common biomaterials for bone repair for other anatomical sites by the modulus-strength chart. This study novelly presented that the mechanical anisotropy match between the scaffold and the trabecular bone could be achieved through a flexible parameterization design of the scaffold via the current methodology, which might offer promising applications in the fields of the bone tissue engineering and the regenerative medicine.