Development of cell adhesive factor coated-implant having high bone inductive ability.

羟基磷灰石(HA)是一种活泼的牙科种植材料，可加速其表面的骨形成。这种加速的机制尚不清楚。细胞黏附的阐明可能是理解HA生物活性机制的关键。在本研究中，我们分析了HOS人成骨细胞在HA和钛上的黏附，以找出与HA的特殊黏附。在短期培养中，在胎牛血清预涂覆材料中，HA上的细胞黏附数量明显高于钛。此外，还测试了磷酸盐缓冲盐水预涂层和牛血清白蛋白预涂层材料的无血清条件。在所有预包被条件下，结果几乎相同，表明细胞粘附量不受血清成分的影响。然而，在扫描电子显微镜的形态观察中发现，不同的预涂覆条件下，涂层的结合形式不同。有血清预涂膜后，成骨细胞在羟基磷灰石和钛表面紧密贴附和铺展，而在无血清预涂覆的情况下，成骨细胞贴壁松散，不能铺展。为了评价精氨酸-甘氨酸-天冬氨酸(Arg-Gly-Asp，RGD)序列特异性粘附性，用人工合成的RGD多肽进行竞争抑制试验。结果表明，RGD多肽能显著抑制成骨细胞在HA上的紧密黏附和铺展，而对钛上的黏附和铺展无明显抑制作用。这些结果表明，细胞对HA的黏附调节不同于对钛的黏附。我们的研究表明，含RGD的血清蛋白可能在调节成骨细胞与[IA]的特异性黏附以及诱导细胞生长和分化方面发挥重要作用。

Hydroxyapatite (HA) is a bloactive dental implant material which accelerates bone formation on its surface. The mechanism of this acceleration is not clear. The elucidation of the cell adhesion might be the key to understanding the bioactive mechanism of HA.In this study, we analyzed the adhesion of HOS human osteoblasts onto HA and titanium to find out the particular adhesion to HA.In short-term cultures in fetal bovine serum-precoated materials, a significantly higher number of cells adhered to HA than to titanium. In addition, serum-free conditions with phosphate buffered-saline precoating or bovine serum albumin precoating materials were tested. The results were nearly the same among all precoating conditions, suggesting that the quantity of cell adhesion was not affected by serum components. However, in the morphological observation by SEM, the form of adhesion was found to differ among precoating conditions. The osteoblasts tightly adhered and spread onto both HA and titanium with serum precoating, whereas the cells loosely adhered and did not spread without serum. To evaluate the Arg-Gly-Asp (RGD) sequence-specific adhesion, synthetic RGD peptides were used for a competitive inhibition test. The result showed that RGD peptides remarkably inhibited the tight adhesion and spreading of osteoblasts onto HA, whereas it did not strongly inhibit these onto titanium. These results demonstrate that the regulation of cell adhesion to HA is different from that to titanium. Our study suggests that the RGD-containing serum proteins might have a major role in regulating the specific adhesion of osteoblasts to [IA, and in inducing enhanced cell growth and differentiation.