Naslov
Dielectric response of genomic DNA solutions: preparation, spectrophotometry and dielectric spectroscopy measurements

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

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

Izvornik
From Solid State to BioPhysics II / Forro, Laszlo ; Pavuna, Davor - Lausanne : École polytechnique fédérale de Lausanne (EPFL), 2004

Skup
From Solid State to BioPhysics II

Mjesto i datum
Cavtat, Hrvatska, 26.06.2004. - 02.07.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
genomic DNA solutions; spectrophotometry; dielectric spectroscopy

Sažetak
Dielectric spectroscopy measurements on DNA samples in solution have been performed by many researchers in the nineteen eighties. However, contradictory results were reported and no definite knowledge has been reached. Experimental issues like the electrode polarization effect and data analysis, which was rather poor and also did not allow to resolve reliably two close modes in frequency, might be blamed partially. We prepared a range of solutions, covering three decades in concentration, of salmon sperm Na-DNA in pure water and of pure lyophilized (no buffer) calf thymus DNA in pure water and in NaCl electrolyte. Concentrations of DNA solutions were determined using Varian UV-visible spectrophotometer at wavelength of 260 nm. The DNA dielectric response was measured by using a home-made capacitive chamber in conjunction with the Agilent 4294A precision impedance analyzer from 40 Hz to100 MHz and at temperatures between +5 oC and +40 oC. An important experimental issue that deserves scrutiny is the electrode polarization effect, which grows in magnitude with lowering the frequency. We addressed this issue in the way that we measured the response of the background solution, which was subtracted from the total measured response in order to obtain the intrinsic DNA relaxation. This procedure removes background influences and improves sensitivity of the measurement. DNA relaxation data were fitted by the generalized Debye function using the least squares method in the complex plane.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Biologija

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