Interfacial Electron-Shuttling Processes across KolliphorEL Monolayer Grafted Electrodes

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• 作者：Khadijeh Nekoueian ; Christopher E. Hotchen ; Mandana Amiri ; Mika Sillanp盲盲 ; Geoffrey W. Nelson ; John S. Foord ; Philip Holdway ; Antoine Buchard ; Stephen C. Parker ; Frank Marken
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：July 22, 2015
• 年：2015
• 卷：7
• 期：28
• 页码：15458-15465
• 全文大小：491K
• ISSN：1944-8252

文摘

Covalently grafted KolliphorEL (a poly(ethylene glycol)-based transporter molecule for hydrophobic water-insoluble drugs; MW, ca. 2486; diameter, ca. 3 nm) at the surface of a glassy-carbon electrode strongly affects the rate of electron transfer for aqueous redox systems such as Fe(CN)₆^{3鈥?4鈥?/sup>. XPS data confirm monolayer grafting after electrochemical anodization in pure KolliphorEL. On the basis of voltammetry and impedance measurements, the charge transfer process for the Fe(CN)₆3鈥?4鈥?/sup> probe molecule is completely blocked after KolliphorEL grafting and in the absence of a 鈥済uest鈥? However, in the presence of low concentrations of suitable ferrocene derivatives as guests, mediated electron transfer across the monolayer via a shuttle mechanism is observed. The resulting amplification of the ferrocene electroanalytical signal is investigated systematically and compared for five ferrocene derivatives. The low-concentration electron shuttle efficiency decreases in the following sequence: (dimethylaminomethyl)ferrocene > n-butyl ferrocene > ferrocene dimethanol > ferroceneacetonitrile > ferroceneacetic acid.}