Naslov
Dielectric spectroscopy of genomic DNA solutions

Autori
Vuletić, Tomislav ; Tomić, Silvia ; Dolanski Babić, Sanja ; Krča, Sanja ; Ivanković, Dušica ; Griparić, Lorena

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
The 5th International Conference on Biological Physics / - Gothenburg : Goeteborgs Universitet, 2004

Skup
The 5th International Conference on Biological Physics

Mjesto i datum
Göteborg, Švedska, 23.08.2004. - 27.08.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
DNA dielectric relaxation; dielectric spectroscopy of biomaterials

Sažetak
Background/aim: The transport of electrical signals in bio-materials, and in particular in the key biological molecule Deoxyribonucleic acid (DNA), on a molecular scale is of fundamental interest in the life sciences. The highly anisotropic structure of DNA implies that the conduction process should be extremely sensitive to the internal structure and to the local environment of the DNA double helix. The aim of this research is to contribute in revealing the dynamical properties of native DNA as a function of its aqueous environment, like electrolyte concentration, counter-ion and pH. Methods: We employed low frequency dielectric spectroscopy in the frequency range of 100 Hz to 100 MHz (LFDS) in conjunction with home-made chamber for samples in solution. LFDS is a non-destructive tool, which can be used for detecting and quantifying the polarization response of DNA in liquid environment. Because DNA is a highly charged molecule, in an applied low-frequency ac electric field, its polarization response, in combination with the motion of the surrounding ions, can be substantial. Results: The home-made chamber is designed for measurement of liquid samples of small volume, 50-200  L, having conductivity in the range of 2- 2000  S/cm. Temperature stabilization is &plusmn ; ; ; 10 mK in the range of -20 - +60 oC. Reproducibility is 1.5% and the measured sample stability is achieved on the time scale of 2 hours. We will show results obtained on (1) a wide concentration range of salmon sperm Na-DNA solutions in pure water, and on (2) a wide concentration range of pure lyophilized (no buffer) calf thymus DNA solutions in pure water and in NaCl electrolyte. Conclusions: We discuss the possible assignments of observed relaxation modes taking into account the value and the concentration dependence of the dielectric relaxation parameters obtained from fits to the generalized Debye function (the dielectric strength, the central relaxation time and the distribution of relaxation times).

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Biologija

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