Electrochemical impedance spectroscopy of single-stranded and double-helical polynucleotides
| Authors | |
|---|---|
| Year of publication | 2000 |
| Type | Article in Proceedings |
| Conference | Book of Abstracts, J.Heyrovský Memorial Symposium, Praha |
| MU Faculty or unit | |
| Citation | |
| Field | Biophysics |
| Keywords | DNA adsorption; electrode double layer; impedance spectroscopy |
| Description | The dependence of the impedance of the electrode double layer on time and frequency around the potentials of the tensammetric peaks and around the potential of maximum adsorption of single-stranded and double-helical polyadenylic acid (poly A) and DNA was studied. At room temperature the single stranded poly A (pH 8) yields a high tensammetric peak at about -1.4 V vs.SCE. The peak is higher and narrower at low ionic strengths. The height of the peak decreases with increasing frequency at low ionic strengths while it is almost independent on the frequency at higher ionic strengths. With double-helical (native ) DNA only one desorption maximum is observed on the C-E curves, single-stranded (denatured) DNA yields two maxima. It was shown by Miller and later by Palecek that the more positive desorption peak at -1.15 V yielded both by the native and denatured DNA corresponds to the desorption of the sugar - phospate backbone. The more negative peak at -1.4 V which yields only denatured DNA corresponds to the more firmly adsorbed bases. |
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