Takahashi K, van den Beucken J J J P, Wolke J G C, Hayakawa T, Nishiyama N, Jansen J A
Department of Dental Materials, Nihon University Graduate School of Dentistry at Matsudo, 2-870-1, Sakaecho Nishi, Matsudo, Chiba 271-8587, Japan.
J Biomed Mater Res A. 2008 Mar 1;84(3):682-90. doi: 10.1002/jbm.a.31341.
The objective of this study was to characterize the physicochemical, dissolution, and osteogenic properties of radio frequency magnetron sputtered dicalcium pyrophosphate/tricalciumphosphate (Pyro/TCP) and hydroxylapatite (HA) coatings. Therefore Pyro/TCP and HA coatings were deposited on grit-blasted titanium discs. The results showed that the deposited coatings were amorphous and changed into a crystalline structure after IR heat-treatment of 550 degrees C for HA and 650 degrees C for Pyro/TCP. Heat-treated HA coatings appeared to be stable during immersion in simulated body fluid (SBF), that is no changes in the XRD pattern were observed. Also, no dissolution of the coating was observed by scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) revealed that the Ca/P ratio of the HA coatings remained constant during SBF immersion. On the other hand, the heat-treated Pyro/TCP coatings showed a surface reaction of calcium pyrophosphate into a beta-tricalcium phosphate phase during SBF immersion. This was confirmed by EDS analysis. Rat bone marrow-derived osteoblast-like cells cultured on the heat-treated substrates showed that cell proliferation and differentiation occurred on both types of bioceramic coatings. No significant differences for proliferation and early differentiation were observed between cells cultured on heat-treated Pyro/TCP and HA at individual time points. However, osteocalcin expression, a late marker for osteoblast-like cell differentiation, was significantly increased after 12 days of culture on HA-coatings. These results were confirmed by SEM observations and suggest increased osteogenic properties for HA-coatings over Pyro/TCP-coatings. Additional research is necessary to obtain conclusive evidence on the in vivo osteogenic capacity of Pyro/TCP coatings.
本研究的目的是表征射频磁控溅射焦磷酸二钙/磷酸三钙（Pyro/TCP）和羟基磷灰石（HA）涂层的物理化学、溶解和成骨特性。因此，将Pyro/TCP和HA涂层沉积在喷砂处理的钛盘上。结果表明，沉积的涂层为非晶态，在550℃对HA和650℃对Pyro/TCP进行红外热处理后转变为晶体结构。经热处理的HA涂层在模拟体液（SBF）中浸泡时似乎很稳定，即XRD图谱未观察到变化。此外，通过扫描电子显微镜（SEM）未观察到涂层的溶解。能量色散光谱（EDS）显示，HA涂层在SBF浸泡期间Ca/P比保持恒定。另一方面，经热处理的Pyro/TCP涂层在SBF浸泡期间显示焦磷酸钙表面反应生成β-磷酸三钙相。这通过EDS分析得到证实。在经热处理的基材上培养的大鼠骨髓来源的成骨样细胞表明，两种生物陶瓷涂层上均发生了细胞增殖和分化。在各个时间点，在经热处理的Pyro/TCP和HA上培养的细胞之间，增殖和早期分化没有显著差异。然而，在HA涂层上培养12天后，成骨钙素表达（成骨样细胞分化的晚期标志物）显著增加。这些结果通过SEM观察得到证实，并表明HA涂层比Pyro/TCP涂层具有更强的成骨特性。需要进行更多研究以获得关于Pyro/TCP涂层体内成骨能力的确凿证据。
