Controlled Surface Chemistry of Diamond/β-SiC Composite Films for Preferential Protein Adsorption

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• 作者：Tao Wang ; Stephan Handschuh-Wang ; Yang Yang ; Hao Zhuang ; Christoph Schlemper ; Daniel Wesner ; Holger Sch?nherr ; Wenjun Zhang ; Xin Jiang
• 刊名：Langmuir
• 出版年：2014
• 出版时间：February 4, 2014
• 年：2014
• 卷：30
• 期：4
• 页码：1089-1099
• 全文大小：606K
• ISSN：1520-5827

文摘

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/尾-SiC composite films and its effect on protein adsorption. For systematic and high-throughput investigations, novel diamond/尾-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/尾-SiC ratio of the composite films shows a continuous change from pure diamond to 尾-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/尾-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 尾-SiC, resulting in an increasing amount of proteins adsorbed to the gradient surfaces with increasing diamond/尾-SiC ratio. By contrast, for hydrogen-treated surfaces, the proteins preferentially adsorbed on 尾-SiC, leading to a decreasing amount of albumin adsorbed on the gradient surfaces with increasing diamond/尾-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/尾-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.