Depth-Resolved Structural and Compositional Characterization of Ion-Implanted Polystyrene that Enables Direct Covalent Immobilization of Biomolecules

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• 作者：Marcela Milena Marie Bilek ; Alexey Kondyurin ; Stephen Dekker ; Bradley Clifton Steel ; Richard Arthur Wilhelm ; Ren茅 Heller ; David Robert McKenzie ; Anthony Steven Weiss ; Michael James ; Wolfhard M枚ller
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 23, 2015
• 年：2015
• 卷：119
• 期：29
• 页码：16793-16803
• 全文大小：542K
• ISSN：1932-7455

文摘

A polystyrene film spun onto polished silicon substrates was implanted with argon ions using plasma immersion ion implantation (PIII) to activate its surface for single-step immobilization of biological molecules. The film was subsequently investigated by X-ray and neutron reflectometry, ultraviolet (UV)鈥搗isible (vis) and Fourier transform infrared (FTIR) ellipsometry, FTIR and Raman spectroscopy, as well as nuclear reaction analysis to determine the structural and compositional transformations associated with the surface activation. The ion irradiation resulted in a significant densification of the carbon structure, which was accompanied by hydrogen loss. The density and hydrogen profiles in the modified surface layers were found to agree with the expected depths of ion implantation as calculated by the Stopping and Range of Ions in Matter (SRIM) software. The data demonstrate that the reduction in film thickness is due to ion-induced densification rather than the removal of material by etching. Characterization by FTIR, atomic force microscopy (AFM), ellipsometry, and X-ray reflectometry shows that polystyrene films modified in this way immobilize dense layers of protein (tropoelastin) directly from solution. A substantial fraction of the immobilized protein layer remains after rigorous washing with sodium dodecyl sulfate solution, indicating that its immobilization is by covalent bonding.