Induction and Acceleration of Bonelike Apatite Formation on Tantalum Oxide Gel in Simulated Body Fluid
Induction and Acceleration of Bonelike Apatite Formation on Tantalum Oxide Gel in Simulated Body Fluid
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模拟体液中氧化钽凝胶诱导和加速骨状磷灰石形成
DOI：
10.1023/a:1011265701447
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发表时间：
2001
影响因子：
2.5
通讯作者：
Takashi Nakamura
中科院分区：
文献类型：
--
作者：
T. Miyazaki;Hyunmin Kim;T. Kokubo;H. Kato;Takashi Nakamura
未经处理的钽金属在模拟体液（SBF）中经过长时间处理后，其表面会形成骨状磷灰石层。当金属预先经过 NaOH 和热处理以在其表面形成无定形钽酸钠时，钽金属上的磷灰石形成显着加速。磷灰石在 NaOH 和热处理的钽金属上的快速形成解释如下。金属表面的钽酸钠与SBF中的H3O+离子交换，释放出Na+离子，在其表面形成大量的Ta-OH基团。由此形成的 Ta-OH 基团诱导磷灰石成核，并且由于 OH− 离子浓度的增加，释放的 Na+ 离子通过增加 SBF 中磷灰石的离子活性积来加速磷灰石成核。在本研究中，为了证实这一解释，研究了通过溶胶-凝胶法制备的不同Na/Ta原子比的钽酸钠凝胶上磷灰石的形成。研究发现，即使是不含 Na2O 的氧化钽凝胶，在 SBF 中也会在其表面形成磷灰石。这证明凝胶上丰富的Ta-OH基团可以诱导磷灰石成核。凝胶的磷灰石形成能力随着凝胶的Na/Ta原子比的增加而增加。含钠钽氧化物凝胶释放Na+离子，其量随着凝胶Na/Ta原子比的增加而增加。释放的 Na+ 离子使 SBF 的 pH 值增加。这些结果证明，通过增加SBF中磷灰石的离子活度乘积，释放的Na+离子加速了Ta-OH基团诱导的磷灰石成核。
Untreated tantalum metal forms bonelike apatite layer on its surface in a simulated body fluid (SBF) after a long period. The apatite formation on the tantalum metal is significantly accelerated, when the metal was previously subjected to NaOH and heat treatments to form an amorphous sodium tantalate on its surface. The fast formation of the apatite on the NaOH- and heat-treated tantalum metal was explained as follows. The sodium tantalate on the surface of the metal releases the Na+ ion via exchange with H3O+ ion in SBF to form a lot of Ta-OH groups on its surface. Thus formed Ta-OH groups induce the apatite nucleation and the released Na+ ion accelerates the apatite nucleation by increasing ionic activity product of the apatite in SBF due to increase in OH− ion concentration. In the present study, in order to confirm this explanation, apatite formations on sodium tantalate gels with different Na/Ta atomic ratios, which were prepared by a sol-gel method were investigated. It was found that even Na2O-free tantalum oxide gel forms the apatite on its surface in SBF. This proves that the Ta-OH groups abundant on the gel can induce the apatite nucleation. The apatite-forming ability of the gels increased with increasing Na/Ta atomic ratios of the gels. The sodium-containing tantalum oxide gels released the Na+ ion, the amount of which increased with increasing Na/Ta atomic ratios of the gels. The released Na+ ion gave an increase in pH of SBF. These results prove that the apatite nucleation induced by the Ta-OH groups is accelerated with the released Na+ ion by increasing ionic activity product of the apatite in SBF.