Yeung W K, Sukhorukova I V, Shtansky D V, Levashov E A, Zhitnyak I Y, Gloushankova N A, Kiryukhantsev-Korneev P V, Petrzhik M I, Matthews A, Yerokhin A
University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK. Email:
National University of Science and Technology 'MISiS', Leninsky prospect 4, Moscow 119049, Russia.
RSC Adv. 2016 Feb 12;6(15):12688-12698. doi: 10.1039/c5ra22178a. Epub 2016 Feb 1.
The enhancement of the biological properties of Ti by surface doping with hydroxyapatite (HA) is of great significance, especially for orthodontic applications. This study addressed the effects of HA particle size in the electrolyte suspension on the characteristics and biological properties of thin titania-based coatings produced on Ti-6Al-4V alloy by plasma electrolytic oxidation (PEO). Detailed morphological investigation of the coatings formed by a single-stage PEO process with two-step control of the electrical parameters was performed using the Minkowski functionals approach. The surface chemistry was studied by glow discharge optical emission spectroscopy and Fourier transform infrared spectroscopy, whereas mechanical properties were evaluated using scratch tests. The biological assessment included evaluation of the coating bioactivity in simulated body fluid (SBF) as well as studies of spreading, proliferation and osteoblastic differentiation of MC3T3-E1 cells. The results demonstrated that both HA micro- and nanoparticles were successfully incorporated in the coatings but had different effects on their surface morphology and elemental distributions. The micro-particles formed an irregular surface morphology featuring interpenetrated networks of fine pores and coating material, whereas the nanoparticles penetrated deeper into the coating matrix which retained major morphological features of the porous TiO coating. All coatings suffered cohesive failure in scratch tests, but no adhesive failure was observed; moreover doping with HA increased the coating scratch resistance. tests in SBF revealed enhanced bioactivity of both HA-doped PEO coatings; furthermore, the cell proliferation/morphometric tests showed their good biocompatibility. Fluorescence microscopy revealed a well-organised actin cytoskeleton and focal adhesions in MC3T3-E1 cells cultivated on these substrates. The cell alkaline phosphatase activity in the presence of ascorbic acid and β-glycerophosphate was significantly increased, especially in HA nanoparticle-doped coatings.
通过用羟基磷灰石（HA）进行表面掺杂来增强钛的生物学性能具有重要意义，特别是在正畸应用方面。本研究探讨了电解质悬浮液中HA粒径对通过等离子体电解氧化（PEO）在Ti-6Al-4V合金上制备的二氧化钛基薄膜涂层的特性和生物学性能的影响。使用闵可夫斯基泛函方法对通过单阶段PEO工艺并采用两步电参数控制形成的涂层进行了详细的形态学研究。通过辉光放电光发射光谱和傅里叶变换红外光谱研究了表面化学，而通过划痕试验评估了机械性能。生物学评估包括对涂层在模拟体液（SBF）中的生物活性的评估以及对MC3T3-E1细胞的铺展、增殖和成骨细胞分化的研究。结果表明，HA微米颗粒和纳米颗粒均成功掺入涂层中，但对其表面形态和元素分布有不同影响。微米颗粒形成了不规则的表面形态，其特征是细孔和涂层材料相互贯穿的网络，而纳米颗粒更深地渗透到涂层基质中，该基质保留了多孔TiO涂层的主要形态特征。所有涂层在划痕试验中均发生内聚破坏，但未观察到粘附破坏；此外，用HA掺杂提高了涂层的耐划痕性。在SBF中的试验表明，两种HA掺杂的PEO涂层的生物活性均增强；此外，细胞增殖/形态测量试验表明它们具有良好的生物相容性。荧光显微镜显示在这些基质上培养的MC3T3-E1细胞中肌动蛋白细胞骨架组织良好且有粘着斑。在存在抗坏血酸和β-甘油磷酸的情况下，细胞碱性磷酸酶活性显著增加，特别是在HA纳米颗粒掺杂的涂层中。
