Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, 188 Longwood Avenue, Boston, MA, USA.
Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, 188 Longwood Avenue, Boston, MA, USA.
J Nanobiotechnology. 2019 Mar 1;17(1):34. doi: 10.1186/s12951-019-0467-1.
Natural teeth are supported by connective tissue collagen fibers that insert perpendicularly in the tooth cementum. Perpendicular insertion plays an important role in the maintenance of the junction between the oral epithelium and the periodontal connective tissue. Most titanium dental implant surfaces have no micro or macro structure to support perpendicularly oriented collagen attachment. Without this tight biologic seal to resist bacterial invasion and epithelial downgrowth, progressive bone loss in peri-implantitis is seen around dental implants. The purpose of this study was to establish the perpendicularly oriented collagen attachment to titanium oxide nanotube (TNT), and to assess its binding stability. TNT was prepared on the titanium-surface by anodization. Scanning electron microscopy (SEM) showed a regularly aligned TNT with an average 67 nm-diameter when anodized at 30 V for 3 h. Subsequently, collagen type I (CoI) was electrophoretically fused to anodic TNT in native polyacrylamide gel system where negatively charged CoI-C term was perpendicularly navigated to TNT. SEM and atomic force microscopy (AFM) were used to analyze CoI on the TiO and TNT surface. Several tens of nanometers of CoI protrusion were recorded by AFM. These protrusions may be long enough to be priming sites for cell-secreted CoI. CoI laid parallel to the titanium surface when fused by a chemical linker. Binding resistance of CoI against drastic ultrasonication was measured by Fourier-transform infrared spectroscopy attenuated total reflection (FTIR-ATR). The electrophoretically fused CoI in the titanium nanotube (TNT-CoI) showed the significantly greatest binding resistance than the other groups (P < 0.01, a 1-way ANOVA and Tukey HSD post hoc test). Furthermore, TNT-CoI surface rejected epithelial cell stretching and epithelial sheet formation. Chemically linked horizontal CoI on titanium oxide (TiO) facilitated epithelial cell stretching and sheet formation.
天然牙齿由垂直插入牙骨质的结缔组织胶原纤维支撑。垂直插入在维持口腔上皮和牙周结缔组织之间的连接中起着重要作用。大多数钛牙科种植体表面没有微观或宏观结构来支撑垂直定向的胶原附着。没有这种紧密的生物密封来抵抗细菌入侵和上皮向下生长，在种植体周围炎中会看到种植体周围的骨逐渐丢失。本研究的目的是建立垂直定向的胶原附着在氧化钛纳米管（TNT）上，并评估其结合稳定性。TNT 通过阳极氧化在钛表面上制备。扫描电子显微镜（SEM）显示，在 30 V 下阳极氧化 3 小时后，TNT 具有规则排列的 TNT，平均直径为 67nm。随后，将 I 型胶原（CoI）通过电泳融合到天然聚丙烯酰胺凝胶系统中的阳极 TNT 中，其中带负电荷的 CoI-C 末端垂直导航到 TNT。SEM 和原子力显微镜（AFM）用于分析 TiO 和 TNT 表面上的 CoI。AFM 记录了数十纳米的 CoI 突出物。这些突起可能足够长，成为细胞分泌的 CoI 的起始位点。当用化学连接子融合时，CoI 平行于钛表面排列。通过傅里叶变换红外光谱衰减全反射（FTIR-ATR）测量 CoI 对剧烈超声处理的结合阻力。在钛纳米管（TNT-CoI）中电泳融合的 CoI 显示出比其他组明显更高的结合阻力（P<0.01，单向方差分析和 Tukey HSD 事后检验）。此外，TNT-CoI 表面排斥上皮细胞拉伸和上皮片形成。在氧化钛（TiO）上化学连接的水平 CoI 促进了上皮细胞拉伸和片层形成。
