Development of a cultured scaffold-cell construct made of carbonate apatite and osteoblast

点击翻译按钮获取中文摘要

Acid soluble calcium phosphates of tetracalcium phosphate (Te-CP) and α-tricalcium phosphate (α-TCP) were employed to make porous carbonate apatite (CA) samples in solutions containing carbonate under physiological conditions. Te-CP and α-TCP were expected to transform to CA under the conditions used. First Te-CP (or α-TCP) and sugar compact was made and the compact was placed in solutions containing carbonate to allow sugar to dissolve and at the same time to encourage Te-CP (or α-TCP) to transform to CA. Surprisingly however, none of them transformed to CA. Dicalcium phosphate dihydrate (DCPD) was the next to use as a precursor phase. From DCPD and sugar compacts, porous CA was obtained at 37℃ in one week in a solution containing 0.1M carbonate. Another method used to prepare porous CA was to employ powdered CA samples that contained about 12wt% carbonate. CA/sugar compacts was immersed in d.w. at 37℃ for less than 60 minutes to allow sugar to dissolve, resulting in a very weak porous form of CA, which was later sintered at 600-750℃ to bestow porous CA samples some mechanical strength. Porous CA thus made was combined with bFGF and implanted in rat skull defects for 12 weeks. At 2 and 12 weeks after implantation, amounts of bone newly formed estimated based on μ-CT images in inside porous areas were significantly greater with CA combined with bFGF than CA alone, indicating that porous forms of CA were useful as a growth factor carrier. Porous forms of CA were also combined with osteoblastic cells and they were implanted subcutaneously in the backs of rats. In 4 weeks bone formed inside implanted porous CA that was combined with osteoblastic cells. With time bone formed increased in amounts and became more matured. No bone was formed with CA alone even at 8 weeks after implantation. These findings suggest that CA/osteoblast hybrid is really osteoinductive, confirming also that CA is very useful as scaffolding to make material/cell hybrid.