Interconnectivity of Bioceramic Scaffolds with Different Porous Structures and Their Fluid Velocity Distribution Analyzed by Micro-CT Computer Modeling

Abstract

Pore interconnectivity is a key parameter for bone tissue engineering scaffolds, which controls penetration of body fluid with proteins and cells, and tissue ingrowth. The present study investigated the porous characteristics of hydroxyapatite (HA) scaffolds prepared via three processes (HA sphere packing, wax sphere-leaching and HA fiber aggregation) by micro-computed tomography (μCT) from following three procedures: (1) modeling of the porous structure by image reconstruction; (2) analysis of porosity along longitudinal direction; and (3) simulation of fluid flow across the scaffold by finite element analysis (FEA). Image analyses revealed that, the scaffolds prepared by the above two methods featured relatively regular porosity distributions, whereas that by HA fiber aggregation had an irregular distribution. Fluid velocity distribution by FEA suggested that scaffolds prepared by HA sphere packing and wax 72 无 机 材 料 学 报 第 30卷 sphere leaching readily allowed penetration of fluid due to their favorable pore interconnectivity. The fluid velocity vector distribution predicted that circular flows dominated near the pore wall in the scaffold prepared by wax sphere leaching. These circular flows may impede the material exchange between cells attached to the pore wall and the body fluid, which may illustrate that the inferior in vivo osteogenic activity of scaffolds prepared by wax sphere leaching when compared with those produced by HA sphere packing.