Ionic mobility in DNA films studied by dielectric spectroscopy

Abdelkader Kahouli (1) , Jessica Valle Orero (2, 3) , Jean-Luc Garden (4) , Michel Peyrard (2)

1 G2ELab - Laboratoire de Génie Electrique de Grenoble
2 Phys-ENS - Laboratoire de Physique de l'ENS Lyon
3 ILL - Institut Laue-Langevin
4 NEEL - Institut Néel

Double-helix DNA molecules can be found under different conformational structures driven by ionic and hydration surroundings. Usually, only the B-form of DNA, which is the only form stable in aqueous solution, can be studied by dielectric measurements. Here, the dielectric responses of DNA molecules in the A- and B-form, oriented co-linearly within fibres assembled in a film have been analyzed. The dielectric dispersion, permittivity and dissipation factor, have been measured as a function of frequency, strength voltage, time, temperature and nature of the counter-ions. Besides a high electrode polarization component, two relaxation peaks have been observed and fitted by two Cole-Cole relaxation terms. In the frequency range that we investigated (0.1Hz to 5 10^6Hz) the dielectric properties are dominated by the mobility and diffusivity of the counter-ions and their interactions with the DNA molecules, which can therefore be characterized for the A- and B-forms of DNA.

Mots clés: dielectric spectroscopy; DNA

Domaines: Mécanique statistique [cond-mat.stat-mech]

Abdelkader Kahouli, Jessica Valle Orero, Jean-Luc Garden, Michel Peyrard. Ionic mobility in DNA films studied by dielectric spectroscopy. European Physical Journal E: Soft matter and biological physics, 2014, 37 (9), pp.82. ⟨10.1140/epje/i2014-14082-5⟩. ⟨ensl-01069225⟩