title: Controlled surface chemistry of diamond/β-SiC composite films for preferential protein adsorption.
abstract: 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.
authors.affiliation: Institute of Materials Engineering, University of Siegen , Paul-Bonatz-Straße 9-11, 57076 Siegen, Germany.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Stephan
authors.initials: S
authors.lastname: Handschuh-Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Hao
authors.initials: H
authors.lastname: Zhuang
authors.forename: Christoph
authors.initials: C
authors.lastname: Schlemper
authors.forename: Daniel
authors.initials: D
authors.lastname: Wesner
authors.forename: Holger
authors.initials: H
authors.lastname: Schönherr
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
mesh_terms: D000327:Adsorption; D000818:Animals; D001672:Biocompatible Materials; D017554:Carbon Compounds, Inorganic / Q000737:chemistry*; D002417:Cattle; D018130:Diamond / Q000737:chemistry*; D005340:Fibrinogen / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D008855:Microscopy, Electron, Scanning; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D017554:Carbon Compounds, Inorganic; D017655:Silicon Compounds; D012710:Serum Albumin, Bovine; D018130:Diamond; D006859:Hydrogen; D005340:Fibrinogen; C022088:silicon carbide