An Evaluation in Microstructural Properties of Xenogeneic Cancellous Bone Being Scaffold Subjected to Mechanical Strain in Bone Tissue Engineering

Abstract

The aim of this study was to investigate the threedimensional microstructure of bovine cancellous bone as an ideal scaffold for bone tissue engineering using a highresolution micro-Computed Tomography (micro-CT) system. The xenogeneic cancellous bone harvested from bovine ilium was scanned by the micro-CT after a set of physicochemical treatment. The structural parameters obtained from micro-CT were analyzed to evaluate biomechanical properties of the xenogeneic cancellous bone used as the scaffold in bone tissue engineering. The bone volume fraction (BV/TV), degree of anisotropy(DA), Euler Number, trabecular thickness (Tb.Th), and the three radii of the mean intercept length (MIL) ellipsoid (a1,a2, and a3) were recorded. A non-invasive visualization and measurement was explored effectively by combining micro-CT as a novel imaging technology with Finite Element (FE) method.Surface meshes generated in medical image processing software MIMICS based on micro-CT images were converted into finite element models which were assigned material properties according to the Gray Value. All the FE models of samples were ultimately subjected to physiological apparent strain using FE analysis software to figure out the local strain. This approach also shed light on the correlation between strain and stress about the specific scaffold material. The results showed that the four microstructural parameters in both strain groups were in normal distribution and homogeneity of variance, except for Euler Number, and no statistically significant change in both different load groups could be detected. Moreover, for an accurate prediction of the mechanical properties of the xenogeneic cancellous bone, it was more reasonable that bone mineral density was made correlate with the Gray Value of segmented 3D images, which were better than those studies based on the isotropy hypothesis.