Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Tsukuba 305-0044, Japan.
Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Tsukuba 305-0044, Japan.
Acta Biomater. 2015 Jan;11:520-30. doi: 10.1016/j.actbio.2014.09.026. Epub 2014 Oct 1.
Octacalcium phosphate (OCP) and hydroxyapatite (HAp) coatings were formed on Mg-3 mass% Al-1 mass% Zn (AZ31) magnesium alloy by a single-step chemical solution deposition method. Chemically polished AZ31 (Cpol-AZ31) and HAp- and OCP-coated AZ31 (HAp- and OCP-AZ31) were immersed in a medium for 52 weeks or implanted in transgenic mice for 16 weeks to examine the long-term corrosion behaviour and in situ inflammation behaviour. In the medium, Mg-ion release was restricted for the initial several days and the corrosion rate thereafter was suppressed by approximately one-half with the HAp and OCP coatings. HAp-AZ31 showed a ∼20% lower corrosion rate than OCP-AZ31. Tissues of the transgenic mouse emit fluorescence in proportion to the degree of inflammation in situ. The luminescence intensity level was too low to be a problem regardless of the coatings. A thinner fibrous tissue layer was formed around OCP- and HAp-AZ31 than around Cpol-AZ31, indicating that the HAp and OCP coatings suppressed corrosion and foreign-body reaction in vivo. Visible pits were formed in filiform and round shapes in vitro and in vivo, respectively. Corrosion was observed underneath the coatings, and almost uniform corrosion took place in vitro, while local corrosion was predominant in vivo. These differences in corrosion morphology are attributed to the adhesion of tissues and the lower diffusivity on the surface in vivo than that in vitro. Dissolution behaviour of OCP crystals in vivo was different from that in vitro. It was demonstrated that the HAp and OCP coatings developed have great potential for a biocompatible and corrosion protection coating.
八钙磷酸盐（OCP）和羟基磷灰石（HAp）涂层通过一步化学溶液沉积法沉积在 Mg-3 质量%Al-1 质量%Zn（AZ31）镁合金上。对 AZ31 进行化学抛光（Cpol-AZ31）和 HAp 和 OCP 涂层 AZ31（HAp 和 OCP-AZ31）进行了长达 52 周的浸泡或在转基因小鼠中植入 16 周，以检查长期腐蚀行为和原位炎症行为。在介质中，Mg 离子的释放在前几天受到限制，此后，HAp 和 OCP 涂层将腐蚀速率抑制了约一半。HAp-AZ31 的腐蚀速率比 OCP-AZ31 低约 20%。转基因小鼠的组织会根据原位炎症的程度发出荧光。发光强度水平太低，不会造成任何问题，无论是否有涂层。OCP 和 HAp-AZ31 周围形成的纤维组织层比 Cpol-AZ31 更薄，表明 HAp 和 OCP 涂层抑制了体内腐蚀和异物反应。在体外和体内分别形成了丝状和圆形的可见凹坑。在涂层下观察到腐蚀，体外几乎发生均匀腐蚀，而体内主要发生局部腐蚀。这些腐蚀形态的差异归因于体内组织的附着和表面扩散性比体外低。体内 OCP 晶体的溶解行为与体外不同。结果表明，开发的 HAp 和 OCP 涂层具有作为生物相容和腐蚀保护涂层的巨大潜力。
