The Role of Magnesium Ion Substituted Biphasic Calcium Phosphate Spherical Micro-Scaffolds in Osteogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stem Cells.

This study was investigated the role of magnesium (Mg2+) ion substituted biphasic calcium phosphate (Mg-BCP) spherical micro-scaffolds in osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs). Mg-BCP micro-scaffolds with spherical morphology were successfully prepared using in situ co-precipitation and spray drying atomization process. The in vitro cell proliferation and differentiation of hAT-MSCs were determined up to day 14. After in vitro biological tests, Mg-BCP micro-scaffolds with hAT-MSCs showed more enhanced osteogenicity than pure hAT-MSCs as control group by unique biodegradation of TCP phase and influence of substituted Mg2+ ion in biphasic nanostructure. Therefore, these results suggest that Mg-BCP micro-scaffolds promote osteogenic differentiation of hAT-MSCs.

Hydroxyapatite scaffolds processed using a TBA-based freeze-gel casting/polymer sponge technique.

A novel freeze-gel casting/polymer sponge technique has been introduced to fabricate porous hydroxyapatite scaffolds with controlled "designer" pore structures and improved compressive strength for bone tissue engineering applications. Tertiary-butyl alcohol (TBA) was used as a solvent in this work. The merits of each production process, freeze casting, gel casting, and polymer sponge route were characterized by the sintered microstructure and mechanical strength. A reticulated structure with large pore size of 180-360 microm, which formed on burn-out of polyurethane foam, consisted of the strut with highly interconnected, unidirectional, long pore channels (approximately 4.5 microm in dia.) by evaporation of frozen TBA produced in freeze casting together with the dense inner walls with a few, isolated fine pores (<2 microm) by gel casting. The sintered porosity and pore size generally behaved in an opposite manner to the solid loading, i.e., a high solid loading gave low porosity and small pore size, and a thickening of the strut cross section, thus leading to higher compressive strengths.

In vivo evaluation of porous hydroxyapatite/chitosan-alginate composite scaffolds for bone tissue engineering.

Porous hydroxyapatite (HAp)/chitosan-alginate composite scaffolds were prepared through in situ co-precipitation and freeze-drying for bone tissue engineering. The composite scaffolds were highly porous and interconnected with a pore size of around 50-220 µm at low concentrations of HAp. As the HAp content increased, the porosity of the scaffolds decreased from 84.98 to 74.54%. An MTT assay indicates that the obtained scaffolds have no cytotoxic effects on MG-63 cells, and that they have good biocompatibility. An implantation experiment in mouse skulls revealed that the composite scaffold provides a strong positive effect on bone formation in vivo in mice. Furthermore, that HAp/chitosan-alginate composite scaffold has been shown to be more effective for new bone generation than chitosan-alginate scaffold.