Wang Tao, Handschuh-Wang Stephan, Yang Yang, Zhuang Hao, Schlemper Christoph, Wesner Daniel, Schönherr Holger, Zhang Wenjun, Jiang Xin
Institute of Materials Engineering, University of Siegen , Paul-Bonatz-Straße 9-11, 57076 Siegen, Germany.
Langmuir. 2014 Feb 4;30(4):1089-99. doi: 10.1021/la404277p. Epub 2014 Jan 22.
Diamond and SiC both process extraordinary biocompatible, electronic, and chemical properties. A combination of diamond and SiC may lead to highly stable materials, e.g., for implants or biosensors with excellent sensing properties. Here we report on the controllable surface chemistry of diamond/β-SiC composite films and its effect on protein adsorption. For systematic and high-throughput investigations, novel diamond/β-SiC composite films with gradient composition have been synthesized using the hot filament chemical vapor deposition (HFCVD) technique. As revealed by scanning electron microscopy (SEM), the diamond/β-SiC ratio of the composite films shows a continuous change from pure diamond to β-SiC over a length of ∼ 10 mm on the surface. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to unveil the surface termination of chemically oxidized and hydrogen treated surfaces. The surface chemistry of the composite films was found to depend on diamond/β-SiC ratio and the surface treatment. As observed by confocal fluorescence microscopy, albumin and fibrinogen were preferentially adsorbed from buffer: after surface oxidation, the proteins preferred to adsorb on diamond rather than on β-SiC, resulting in an increasing amount of proteins adsorbed to the gradient surfaces with increasing diamond/β-SiC ratio. By contrast, for hydrogen-treated surfaces, the proteins preferentially adsorbed on β-SiC, leading to a decreasing amount of albumin adsorbed on the gradient surfaces with increasing diamond/β-SiC ratio. The mechanism of preferential protein adsorption is discussed by considering the hydrogen bonding of the water self-association network to OH-terminated surfaces and the change of the polar surface energy component, which was determined according to the van Oss method. These results suggest that the diamond/β-SiC gradient film can be a promising material for biomedical applications which require good biocompatibility and selective adsorption of proteins and cells to direct cell migration.
金刚石和碳化硅都具有非凡的生物相容性、电子性能和化学性能。金刚石和碳化硅的组合可能会产生高度稳定的材料，例如用于具有优异传感性能的植入物或生物传感器。在此，我们报告了金刚石/β-碳化硅复合薄膜的可控表面化学及其对蛋白质吸附的影响。为了进行系统的高通量研究，采用热丝化学气相沉积（HFCVD）技术合成了具有梯度组成的新型金刚石/β-碳化硅复合薄膜。扫描电子显微镜（SEM）显示，复合薄膜的金刚石/β-碳化硅比例在表面约10毫米的长度上呈现从纯金刚石到β-碳化硅的连续变化。利用X射线光电子能谱（XPS）和飞行时间二次离子质谱（ToF-SIMS）揭示了化学氧化和氢处理表面的表面终止情况。发现复合薄膜的表面化学取决于金刚石/β-碳化硅比例和表面处理。通过共聚焦荧光显微镜观察，白蛋白和纤维蛋白原优先从缓冲液中吸附：表面氧化后，蛋白质更倾向于吸附在金刚石上而不是β-碳化硅上，导致随着金刚石/β-碳化硅比例增加，吸附到梯度表面的蛋白质数量增加。相比之下，对于氢处理表面，蛋白质优先吸附在β-碳化硅上，导致随着金刚石/β-碳化硅比例增加，吸附在梯度表面的白蛋白数量减少。通过考虑水自缔合网络与羟基终止表面的氢键以及根据范奥斯方法确定的极性表面能分量的变化，讨论了蛋白质优先吸附的机制。这些结果表明，金刚石/β-碳化硅梯度薄膜对于需要良好生物相容性以及蛋白质和细胞选择性吸附以引导细胞迁移的生物医学应用可能是一种有前途的材料。
