Escuela de Construcción Civil, Facultad de Ingeniería, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile; Departamento de Ingeniería Metalúrgica y de Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso, Chile.
Escuela de Construcción Civil, Facultad de Ingeniería, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile; Departamento de Ingeniería Mecánica y Metalúrgica, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile.
Bioelectrochemistry. 2020 Dec;136:107622. doi: 10.1016/j.bioelechem.2020.107622. Epub 2020 Jul 31.
Ti-6Al-4V alloy has been widely investigated for biomedical applications due to its low density, high specific strength, and favorable corrosion resistance. However, some reported failures have imposed a challenge to improve bone regeneration and fixation, as well as antibacterial properties. A further opportunity for solving this problem is the introduction of porosity. However, this can induce metallic release and corrosion product formation. In this work, a Ti-6Al-4V alloy was exposed to Hank's solution, sterilized and inoculated with Staphylococcus aureus at 37 °C. Surface analysis was carried out by SEM-EDS and XPS. Electrochemical measurements were also performed using chronopotentiometry at open circuit potential, polarization curves, and electrochemical impedance spectroscopy. After exposure, FE-SEM showed some colonies of S. aureus on the sample with 22% porosity. However, XPS analysis revealed that the presence of bacterium influenced the composition of the oxide layer, even more drastically with the increase in added porosity. Moreover, the impedance analysis showed De Levie's behavior, revealing a reduction of pore resistance and modulus of the impedance in the low frequency range in inoculated medium, and polarization curves showed that the passivity potential range was decreased, whereas the passivity current increased in the presence of the S. aureus.
钛-6 铝-4 钒合金由于其低密度、高强度比和良好的耐腐蚀性而被广泛应用于生物医学领域。然而，一些报道的失效案例对提高骨再生和固定以及抗菌性能提出了挑战。解决这个问题的另一个机会是引入多孔性。然而，这可能会导致金属释放和腐蚀产物的形成。在这项工作中，将 Ti-6Al-4V 合金暴露于 Hank's 溶液中，在 37°C 下用金黄色葡萄球菌进行消毒和接种。通过扫描电子显微镜-能谱（SEM-EDS）和 X 射线光电子能谱（XPS）进行表面分析。还通过恒电流计时电位法、极化曲线和电化学阻抗谱在开路电位下进行电化学测量。暴露后，FE-SEM 显示在具有 22%孔隙率的样品上有一些金黄色葡萄球菌的菌落。然而，XPS 分析表明，细菌的存在会影响氧化层的组成，而随着添加孔隙率的增加，这种影响更为明显。此外，阻抗分析显示出德雷维（De Levie）行为，即在接种介质中，低频范围内的孔电阻和阻抗模量降低，而极化曲线表明，在金黄色葡萄球菌存在的情况下，钝化电位范围减小，而钝化电流增加。
