Removable Partial Prosthodontics, Department of Masticatory Function Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Removable Partial Prosthodontics, Department of Masticatory Function Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
J Mech Behav Biomed Mater. 2019 Dec;100:103393. doi: 10.1016/j.jmbbm.2019.103393. Epub 2019 Aug 8.
Surface charge is one of the essential physicochemical properties of titanium surfaces for extracellular protein adsorption. Titanium surfaces are generally electronegatively charged at physiological pH. Typical cellular adhesive proteins and cell membranes are also negatively charged. Therefore, there are no direct electric interactions between proteins and titanium surfaces at physiological pH. The objective of this study was to determine how different electrical charges on titanium surfaces affect protein adsorption. Commercially pure grade-2 titanium disks, 19 mm in diameter and 1.5 mm in thickness, having acid-etched micro-roughed surfaces, were prepared. Electropositive charge was supplied by soaking in LiOH solution at concentrations of 0.05, 0.1, 0.25, 0.5, and 1.0 M. After LiOH treatment, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were performed. The zeta potential, isoelectric point, and wettability of titanium surfaces were measured. The adsorption levels of proteins, including albumin, laminin, and fibronectin, were evaluated. Osteoblastic cell attachment level was also determined. Incorporation of Li was detected in the oxide layer of titanium without surface morphological modification. The zeta potential was shifted up and the isoelectric point was increased from 3.94 to 5.63 by LiOH treatment. Long-term super-hydrophilicity was also obtained on Li-treated surfaces. The adsorption of albumin and laminin increased with increasing concentration of LiOH treatment solution, whereas fibronectin adsorption was highest upon treatment with 0.25 M. The osteoblastic cell attachment level was shown to be dependent on the amount of fibronectin adsorbed. In conclusion, LiOH treatment enhances biological adhesion on titanium with an increase in surface charge and hydrophilicity. This study suggests that modifying the surface charge provides a direct protein-to-materials interaction and the optimal application of Li should be investigated further.
表面电荷是钛表面用于细胞外蛋白吸附的重要物理化学性质之一。钛表面在生理 pH 值下通常带负电荷。典型的细胞黏附蛋白和细胞膜也带负电荷。因此，在生理 pH 值下，蛋白质与钛表面之间没有直接的静电相互作用。本研究旨在确定钛表面的不同电荷如何影响蛋白质吸附。制备直径为 19 毫米、厚度为 1.5 毫米的商用纯 2 级钛盘，其酸蚀微粗糙表面。通过浸泡在浓度为 0.05、0.1、0.25、0.5 和 1.0 M 的 LiOH 溶液中来提供正电荷。LiOH 处理后，进行 X 射线光电子能谱（XPS）和扫描电子显微镜（SEM）分析。测量钛表面的 ζ 电位、等电点和润湿性。评估蛋白质（包括白蛋白、层粘连蛋白和纤连蛋白）的吸附水平。还测定成骨细胞的附着水平。在没有表面形貌修饰的情况下，钛的氧化层中检测到 Li 的掺入。ζ 电位向上移动，等电点从 3.94 增加到 5.63。经 LiOH 处理后，钛表面还获得了长期的超亲水性。随着 LiOH 处理溶液浓度的增加，白蛋白和层粘连蛋白的吸附增加，而纤连蛋白的吸附在 0.25 M 处理时最高。成骨细胞附着水平取决于吸附的纤连蛋白量。总之，LiOH 处理通过增加表面电荷和润湿性来增强钛的生物黏附性。本研究表明，修饰表面电荷提供了蛋白质与材料之间的直接相互作用，应该进一步研究 Li 的最佳应用。
