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Frequency response analysis of potential-modulated orientation changes of a DNA self assembled layer using spatially resolved fluorescence measurements.

TitleFrequency response analysis of potential-modulated orientation changes of a DNA self assembled layer using spatially resolved fluorescence measurements.
Publication TypeJournal Article
Year of Publication2015
AuthorsCasanova-Moreno, JR, Bizzotto, D
JournalElectrochim. Acta
Volume162
Pagination62–71
Abstract

Characterization of a Au electrode modified with a mixed self-assembled monolayer composed of ssDNA and mercaptohexanol is described using in-situ fluorescence microscopy with particular focus on the study on the homogeneity of the surface in terms of its response to potential perturbation. A change in DNA orientation is driven by the charge on the Au surface, and the extent and the rate of orientation change can be detd. using fluorophore modified DNA and fluorescence. Characterization of the surface is typically performed using techniques that det. the av. characteristics of the surface. Significant differences in the response of various regions of the electrode surface can be obsd. These differences can characterized by potential step-imaging measurements or by frequency response anal. of the fluorescence - potential transfer function. Important for high frequency measurements in these low ionic strength electrolytes is the use of a 4th electrode and shunt capacitor which influences the electrochem. impedance results as well as the optical results. The magnitude of the transfer function was found to vary significantly for different regions on the electrode. The authors demonstrate this for two 95 $μ$m regions that are on either side of a grain boundary. The phase of the transfer function is more sensitive to variations in the rate of reorientation between these two regions compared to considering only the magnitude. The variation in the response over the electrode surface is an important consideration for the DNA-based biosensing devices based on modified electrode interfaces. [on SciFinder(R)]

URLhttp://linkinghub.elsevier.com/retrieve/pii/S0013468614018556
DOI10.1016/j.electacta.2014.09.037