Topographical analyses of proliferation and differentiation of osteoblasts in micro‐ and macropores of apatite‐fiber scaffold

Abstract

A variety of calcium phosphates have been used for bone tissue-engineering applications. We developed porous hydroxyapatite (HAp) ceramics by firing green compacts consisting of spherical carbon beads and HAp fiber. The apatite-fiber scaffold (AFS) forms a three-dimensional network of fibers with two different pore sizes (micro- and macropores). In this study, we investigated cell distribution and fine cell structure in AFS by confocal laser scanning microscopy. Osteoblastic cells were permeated homogenously throughout the scaffold under static culture conditions and grew three-dimensionally in macropores of AFS. Cells penetrated into micropores when they were capable of cell-cell formations. Cell proliferation and differentiation were also evaluated by biochemical and molecular biological approaches. The expression levels of early-phase osteogenic genes in AFS increased immediately, and those of middle-phase genes were maintained during the 2-week study period. Furthermore, the expression of late-phase markers increased gradually during the incubation period. These data indicate that macropores provide sufficient space for cell growth and proliferation and that micropores facilitate cell differentiation via cell-cell networks. This study provides evidence for the effectiveness of three-dimensional culture systems comprising AFS, which mimics the microenvironment of bone cells.

Fabrication and Evaluation of Silicon-Containing Apatite Fiber Scaffolds for Bone Tissue Engineering

“…In the FT-IR spectra of the above Si-AFs, the absorptions assigned to the PO 4 3-groups at 1300-900, 600 and 570 cm -1 and assigned to the OH -group at 3570 cm -1 , were detected. In addition, the absorptions assigned to CO 3 2-groups were detected at 1460, 1420 and 880 cm -1 . These absorptions indicate that the present Si-AFs were consisted of carbonate-containing apatite.…”

“…As previously reported in [8], the Si-AFs were synthesized by a homogeneous precipitation method. Starting solution with a Ca/(P+Si) ratio of 1.67 was prepared by mixing Ca(NO 3 ) 2 4H 2 O, (NH 4 ) 2 HPO 4 , Si(OC 2 H 5 ) 4 (TEOS), (NH 2 ) 2 CO and HNO 3 . The concentrations of TEOS in the starting solution were 0 (AF), 0.8 (0.8Si-AF) and 1.6 mass% (1.6Si-AF).…”

“…Thus, HAp is considered as a material which is suitable for use in the biomedical applications, such as bone grafts and scaffolds for bone tissue engineering [1][2][3]. Although the composition of HAp is similar to that of the bone mineral, there are a number of distinct differences between the two materials, in terms of their trace ion contents.…”

Syntheses of Single-Crystal Apatite Particles with Preferred Orientation to the <i>a</i>- and <i>c</i>-Axes as Models of Hard Tissue and Their Applications

“…54,55 The AFS has excellent biocompatibility in vitro 54,56) and in vivo. 57,58) Using the AFS, we attempted to create tissue-engineered bone 54,55,59,60) as well as tissue-engineered liver.…”

Selective differentiation of bone marrow-derived mesenchymal stromal cells into osteocytes via endochondral ossification in an apatite-fiber scaffold

“…10) Additionally, our recent study showed that AFSs can provide a three-dimensional culture environment and facilitate cell proliferation and differentiation using two different pores. 11) In recent years, mesenchymal stem cells (MSCs) have attracted much interest due to their self-renewing potential and multipotentiality for clinical use.…”