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

在生理条件下，用酸溶性磷酸四钙（Te-CP）和α-磷酸三钙（α-TCP）在含碳酸盐的溶液中制备多孔碳酸盐磷灰石（CA）样品。Te-CP和α-TCP在所使用的条件下预期转化为CA。首先制备Te-CP（或α-TCP）和糖压块，并将压块置于含有碳酸盐的溶液中以允许糖溶解，同时促进Te-CP（或α-TCP）转化为CA。然而，令人惊讶的是，他们中没有一个人转化为CA。磷酸二钙二水合物（DCPD）是下一个用作前体相的。由DCPD和糖压块，在37℃下在含有0.1M碳酸盐的溶液中在一周内获得多孔CA。用于制备多孔CA的另一种方法是采用含有约12wt%碳酸盐的粉末状CA样品。将CA/糖压块浸入d.w.在37℃下加热不到60分钟，使糖溶解，得到非常弱的多孔形式的CA，随后在600-750℃下烧结，以赋予多孔CA样品一定的机械强度。将制备的多孔CA与bFGF复合植入大鼠颅骨缺损区12周。在植入后2周和12周，基于μ-CT图像估计的内部多孔区域中新形成的骨的量在CA与bFGF组合时显著大于单独CA，表明多孔形式的CA可用作生长因子载体。多孔形式的CA也与成骨细胞结合，并将其皮下植入大鼠背部。4周时，植入的多孔CA内与成骨细胞结合形成骨。随着时间的推移，骨形成的数量增加，变得更加成熟。即使在植入后8周，单独使用CA也没有骨形成。这些发现表明，CA/成骨细胞杂交是真正的骨诱导，也证实了CA是非常有用的支架，使材料/细胞杂交。

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.