Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada T6G 2V4.
J Biomed Mater Res B Appl Biomater. 2011 Nov;99(2):291-301. doi: 10.1002/jbm.b.31898. Epub 2011 Sep 27.
Hydroxyapatite (HA) depositions on metallic biomedical implants are widely applied to generate bioactive surfaces in simulated biological environments. Highly ordered anodic ZrO₂ nanotubes have attracted increasing interest for biomedical applications. However, previous reports showed that at least 14-28 days were required to obtain HA coating on ZrO₂ nanotubular arrays under biomimetic condition, thus capability to grow HA coating on ZrO ₂nanotubular at room temperature needs to be enhanced. In the present work, we demonstrate that ZrO₂ nanotubular arrays are suitable for an effective dipping treatment to induce more rapid HA coating. A series of ZrO₂ nanotubular arrays having different dimensions were fabricated in fluoride containing electrolyte. Then, we used a dipping treatment for biomimetic formation of an adhesive HA coating on the nanotubular arrays. The coatings formed rapidly using this procedure under biomimetic conditions and did not require a high-temperature annealing process. The as-formed ZrO₂ nanotubular arrays were treated using several dip-and-dry steps, through which the nanotubular arrays were filled and covered with calcium phosphate (CaP) nucleation sites. The specimens readily grew HA once immersed in the simulated biological fluid after 2 days immersion. The carbonated HA coating had several micron thickness after 8 days of immersion while only a thin layer of CaP were observed on annealed ZrO₂ nanotubes immersed in the same solution for the same duration. Tensile testing showed that bonding strength between HA coating and substrate was 21.6 ± 1.6 MPa. This treatment dramatically improves efficiency for promoting HA formation on anodic ZrO₂ nanotubes at room temperature.
羟基磷灰石 (HA) 在金属生物医学植入物上的沉积广泛应用于在模拟生物环境中生成生物活性表面。高度有序的阳极氧化 ZrO₂ 纳米管因其在生物医学应用中的吸引力而受到越来越多的关注。然而，以前的报告表明，在仿生条件下获得 ZrO₂ 纳米管阵列上的 HA 涂层至少需要 14-28 天，因此需要增强在室温下在 ZrO₂ 纳米管上生长 HA 涂层的能力。在本工作中，我们证明 ZrO₂ 纳米管阵列适合进行有效的浸渍处理以诱导更快的 HA 涂层形成。在含有氟化物的电解液中制备了具有不同尺寸的一系列 ZrO₂ 纳米管阵列。然后，我们使用浸渍处理在纳米管阵列上仿生形成粘性 HA 涂层。使用该程序在仿生条件下可以快速形成涂层，而不需要高温退火过程。用几个浸-干步骤处理形成的 ZrO₂ 纳米管阵列，通过该步骤，纳米管阵列被填充并用钙磷 (CaP) 成核位点覆盖。在浸入模拟生物液 2 天后，浸入溶液中的试样很容易长出 HA。在浸入相同溶液 8 天后，形成了几微米厚的碳酸 HA 涂层，而在相同时间内浸入相同溶液中的退火 ZrO₂ 纳米管上仅观察到一层薄薄的 CaP。拉伸测试表明，HA 涂层与基底之间的结合强度为 21.6±1.6 MPa。该处理极大地提高了在室温下促进阳极氧化 ZrO₂ 纳米管上 HA 形成的效率。
