Electrochemical impedance spectroscopy of native and denatured DNA.
| Authors | |
|---|---|
| Year of publication | 2000 |
| Type | Article in Proceedings |
| Conference | DNA Structure and Interaction - Gregor Mendel Symposium, Book of Abstracts |
| MU Faculty or unit | |
| Citation | |
| Field | Biophysics |
| Keywords | DNA adsorption; electrode double layer; impedance spectroscopy |
| Description | From the frequency dependence of the impedance of the electrode double layer represented in a complex impedance plot (the imaginary component Z'' is plotted against the real component Z', Cole-Cole or Nyquist plot) the electric equivalent circuit of the electrode covered with adsorbed DNA layer was determined. The complex plane impedance plots for DNA exhibited arc shapes, from which the apparent resistance R2 of the layer and the solution resistance R1 was determined. The resistance R2 represents the dielectric losses of the capacitance of the electrode double layer, i.e. the energy lost as a heat which arises due to a friction of charged DNA segments forced to move in a viscous solvent by a.c. electric field. It was found that with DNA solutions the dielectric losses are higher (i.e. the resistance R2 is lower) at the potentials where the desorption takes place than at the potentials of maximum adsorption. The desorption of denatured ssDNA is accompanied by higher dielectric losses than the desorption of native dsDNA. This can be explained by the higher flexibility of denatured DNA compared to the dsDNA resulting in the higher dielectric losses. |
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