Nanostructured positively charged bioactive TiO2 layer formed on Ti metal by NaOH, acid and heat treatments
Nanostructured positively charged bioactive TiO2 layer formed on Ti metal by NaOH, acid and heat treatments
复制标题
DOI：
10.1007/s10856-011-4372-x
复制
发表时间：
2011-08-01
影响因子：
3.7
通讯作者：
Kokubo, Tadashi
中科院分区：
文献类型：
--
作者：
Pattanayak, Deepak K.;Yamaguchi, Seiji;Kokubo, Tadashi
氢氧化钠处理后的钛金属表面有纳米级的粗糙度，且在酸浓度不高的情况下，用盐酸、硝酸或硫酸溶液进行酸处理后仍能保持纳米级的粗糙度。在热处理后，它也仍然存在。氢氧化钠处理制得的钛酸氢钠，只要酸浓度不高，经后续酸处理后即可转化为钛酸氢钠。然后通过热处理将钛酸氢转化为锐钛矿型和金红石型的二氧化钛。经处理的钛金属在模拟体液中表现出很高的磷灰石形成能力，特别是当酸浓度大于10 mm时，无论使用的是哪种酸溶液。这种高磷灰石形成能力在潮湿的环境中保持了很长时间。这种高的磷灰石形成能力归因于在TiO2层上形成的表面正电荷，而不是表面粗糙度或特定晶相。这种带正电的二氧化钛首先选择性地吸附带负电的磷酸根离子，然后是带正电的钙离子，从而诱导磷灰石的形成。经过短时间处理的钛金属表面有望形成磷灰石，即使在活着的系统中也是如此。金属与活骨的结合也有望通过这层磷灰石发生。
Nanometer-scale roughness was generated on the surface of titanium (Ti) metal by NaOH treatment and remained after subsequent acid treatment with HCl, HNO3 or H2SO4 solution, as long as the acid concentration was not high. It also remained after heat treatment. Sodium hydrogen titanate produced by NaOH treatment was transformed into hydrogen titanate after subsequent acid treatment as long as the acid concentration was not high. The hydrogen titanate was then transformed into titanium oxide (TiO2) of anatase and rutile by heat treatment. Treated Ti metals exhibited high apatite-forming abilities in a simulated body fluid especially when the acid concentration was greater than 10 mM, irrespective of the type of acid solutions used. This high apatite-forming ability was maintained in humid environments for long periods. The high apatite-forming ability was attributed to the positive surface charge that formed on the TiO2 layer and not to the surface roughness or a specific crystalline phase. This positively charged TiO2 induced apatite formation by first selectively adsorbing negatively charged phosphate ions followed by positively charged calcium ions. Apatite formation is expected on the surfaces of such treated Ti metals after short periods, even in living systems. The bonding of metal to living bone is also expected to take place through this apatite layer.