INHIBITION OF APATITE FORMATION BY TITANIUM AND VANADIUM IONS
INHIBITION OF APATITE FORMATION BY TITANIUM AND VANADIUM IONS
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DOI：
10.1002/jbm.820231305
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发表时间：
1989-04-01
期刊：
影响因子：
--
通讯作者：
COSMA, V
中科院分区：
文献类型：
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作者：
BLUMENTHAL, NC;COSMA, V
在两个生物相关的体外试验系统中研究了Ti 4+和V 5+离子，以确定它们对羟基磷灰石（HA）形成的影响。系统1涉及从溶液中直接沉淀HA，系统2处理HA晶种的生长。实验在pH恒定器中进行，在pH 7.4、37 ℃和0.15M NaCl下，通过连续记录NaOH吸收，其遵循HA形成动力学。在系统1和2中，Ti以剂量相关的方式降低HA形成动力学，而不延迟HA形成的开始。对于V，系统1中HA增殖速率以剂量相关的方式下降，但曲线显示复杂的形状。在系统2中，V引起HA接种生长速率的降低。以前的工作表明，铝块HA增殖吸附到HA晶体表面上的活性生长位点。相比之下，在这项研究中，V被发现不被吸附到HA的表面。V的作用机制可能涉及对金属离子的水解和溶液络合物形成化学知之甚少。我们在这里已经表明，V离子形成V-PO 4复合物在溶液中的HA形成系统，毫无疑问，这些都参与了机制V抑制HA的形成。另一方面，在这项研究中，Ti被证明与HA晶体的表面结合，这意味着该离子可能会毒害活性晶体生长位点，就像铝一样。Ti-6Al-4V合金广泛应用于非骨水泥型全髋关节植入物。 先前的研究表明，植入后6至12个月，犬体内多孔钛植入物周围的骨组织中的钛浓度比此处使用的高10至100倍。长时间浸出的离子进入种植体界面可能会干扰该区域骨的正常类骨质矿化和重塑过程，这将导致随后的种植体松动。这项研究表明，应进行进一步的体外和动物研究，以确定钛和V离子从植入物中浸出的程度及其对组织矿化的影响。
Ti4+ and V5+ ions were studied in two biologically relevant in vitro tests systems to determine their effect on hydroxyapatite (HA) formation. System 1 involved direct HA precipitation from solution, and system 2 dealt with the growth of HA seed crystals. The experiments were carried out in a pH-stat by continuously recording NaOH uptake, which follows HA formation kinetics, at pH 7.4, 37.degree.C, and 0.15 M NaCl. In systems 1 and 2, Ti decreased HA formation kinetics in a dose-related manner without delaying the onset of HA formation. For V, the rate of HA proliferation decreased in system 1 in a dose-related manner, but the curves displayed a complicated shape. In system 2, V brought about a decrease in the HA seeded growth rate. Previous work has shown that Al blocks HA proliferation by adsorbing to active growth sites on the surface of HA crystals. By contrast, in this study V was found not to be adsorbed to the surface of HA. The mechanism of action of V probably involves the poorly understood hydrolysis and solution complex formation chemistry of the metal ion. We have shown here that V ions form V-PO4 complexes in solution in the HA formation systems; undoubtedly these are involved in the mechanism of V inhibition of HA formation. On the other hand, Ti was shown to bind to the surface of HA crystals in this study, which means that the ion may poison active crystal growth sites, as does aluminum. Ti-6Al-4V alloy is widely used in cementless total hip implants. Previous studies have shown that Ti concentrations 10 to 100 times higher than used here accumulate in osseous tissues around porous Ti implants in dogs 6 to 12 months after implantation. Ions leaching out over long periods of time into the implant interface could interfere with the normal osteoid mineralization and remodeling processes of bone in that region, which would result in subsequent loosening of the implant. This research suggests that further in vitro and animal studies should be carried out to determine the extent of Ti and V ion leaching from implants and their effect on tissue mineralization.