Adsorption of a Carboxylated Silane on Gold: Characterization for Its Rational Use in Hybrid Glass/Gold Substrates

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• 作者：Cheng Wei Tony Yang ; Isaac Martens ; El?d L. Gyenge ; Robin F. B. Turner ; Dan Bizzotto
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 11, 2016
• 年：2016
• 卷：120
• 期：5
• 页码：2675-2683
• 全文大小：491K
• ISSN：1932-7455

文摘

Integrated sensing and biosensing microfluidic systems often require sealing between polysiloxane, glass, and gold interfaces, while maintaining functional support on the gold surface within the cell chamber (e.g., biomolecular interaction analysis). A carboxylated trimethoxysilane (TMS-EDTA) coating has been shown to facilitate the bonding of polydimethylsiloxane (PDMS) to gold and glass slides. In this work, the adsorption of TMS-EDTA onto Au is characterized in order to enable its rational use in hybrid glass/gold substrates. Surface plasmon resonance results suggest that carboxylates are available for streptavidin immobilization. Atomic force microscopy studies indicate that a uniform surface coverage with monolayer thickness is formed. Infrared spectroscopy studies confirm that the carboxyl groups are present. Moreover, there is little evidence of siloxane cross-linking. Electrochemical differential capacitance measurements reveal that the potential-dependent free energies of adsorption are ～?20 to–30 kJ/mol (for potentials between ?0.5 and 0.2 V) in the complex electrolyte solution used. Furthermore, at highly negative potentials (～?1.1 V), TMS-EDTA desorbs from the Au surface. The fundamental knowledge obtained about TMS-EDTA adsorption on Au can be applied to construct robust PDMS-based systems with hybrid glass/gold substrates.