In situ Monitoring of Lysozyme Adsorption onto Bare and Cysteine- or 1-Octadecanethiol-Modified Au Electrodes Using an Electrochemical Quartz-Crystal Impedance System

The adsorption of lysozyme from phosphate-buffered saline (pH 7.4) onto bare and cysteine- or 1-octadecanethiol-modified Au electrodes was investigated in situ using an electrochemical quartz-crystal impedance system (EQCIS). The equivalent circuit parameters and resonant frequencies of the piezoele...

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Bibliographic Details
Published in:Analytical Sciences 2000, Vol.16(8), pp.799-805
Main Authors: ZHANG, You-yu, XIE, Qing-ji, ZHOU, An-hong, YAO, Shou-zhuo
Format: Article
Language:English
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Summary:The adsorption of lysozyme from phosphate-buffered saline (pH 7.4) onto bare and cysteine- or 1-octadecanethiol-modified Au electrodes was investigated in situ using an electrochemical quartz-crystal impedance system (EQCIS). The equivalent circuit parameters and resonant frequencies of the piezoelectric quartz-crystal (PQC) resonance, the value of half peak width of the electroacoustic conductance spectrum (DfG1/2) as well as the electrical double-layer capacitance were obtained and analyzed. The adsorption kinetics was analyzed with a scheme of two consecutive reactions occurring at the interface. The amount of adsorbed lysozyme on a hydrophobic surface was greater than that on a hydrophilic one, and a more negative potential brought a larger amount of adsorbed lysozyme. The standard heterogeneous rate constants of ferricyanide/ferrocyanide before and after the lysozyme adsorption were evaluated.
ISSN:0910-6340
1348-2246
DOI:10.2116/analsci.16.799