后处理工艺对阳极氧化钛生物活性的影响

Influences of post-treatment processes on the bioactivity of anodized titanium

钛及钛合金由于具有良好的力学、生物学性能,已成为良好的骨修复和替换材料。为了改善钛的生物活性,首先采用两步电化学阳极氧化法对金属纯钛进行表面改性,即使之表面形成多孔纳米结构,然后对样品进行不同的后处理,如450℃热处理,NaOH处理,NaOH-CaCl2处理,最后将后处理样品浸泡在人体模拟液(SBF)中,研究磷灰石在样品表面的生长情况。采用X射线衍射(XRD)、带能量散射谱(EDS)的场发射扫描电子显微镜(FE-SEM)、傅里叶变换红外光谱(FT-IR)、电感耦合等离子体发射光谱仪(ICP-OES)等对生成的磷灰石的物相、形貌、元素组成等进行表征。结果表明,非晶TiO2纳米管阵列不能诱导磷灰石在其表面生成,而经450℃退火处理后形成的结晶良好的锐钛矿相TiO2纳米管阵列具有一定生物活性,即可诱导部分磷灰石颗粒在其表面生成。进一步经NaOH-CaCl2溶液后处理可加速羟基磷灰石在样品表面的形成速度,样品在模拟体液(SBF)中浸泡8d后,表面生成的磷灰石厚度约为5μm,磷灰石层是由大量球形颗粒堆积而成的,而球形颗粒是由无数纳米薄片组成的花状结构。

Titanium and titanium alloy have become good bone repair and replacement materials because of their good mechanical and biological properties.In order to improve the bioactivity of pure titanium metal,two-step electrochemical anodic oxidation was adopted to modify the surface of titanium metal,which favors the forma-tion of porous nanostructures on Ti surface.After heat treatment at 450 ℃,the anodized Ti sample was further treated by NaOH solution or NaOH-CaCl2 solution.Finally,the post-treated sample was immersed into a simu-lated body fluid (SBF)to study the growth process and mechanism of apatite on the sample surface.The phase, morphology,elementary composition of the samples were characterized via X-ray diffraction (XRD),field emis-sion scanning electron microscopy (FE-SEM)with the energy dispersive X-ray spectroscopy (EDS),Fourier transform infrared spectrometry (FT-IR),and inductively coupled plasma atomic emission spectrometry (ICP-OES).The results revealed that amorphous TiO2 nanotube arrays can not induce the formation of apatite on its surface.While the well-crystallized anatase nanotube arrays formed after annealing at 450 ℃ has some certain degree of bioactivity,namely,it can induce the formation of some apatite on its surface.Further post-treatment by NaOH-CaCl2 solution can accelerate the formation of hydroxyapatite.Its thicknesses are about 5μm after the post-treated samples are immersed in the simulated body fluid (SBF)for 8 d.The hydroxyapatite layer was composed of many flower-like spheres with nano-flakes.