DIELECTRIC STUDY OF DNA WATER-SYSTEMS BY THE THERMALLY STIMULATED CURRENTS METHOD

The dielectric behaviour of diluted DNA-water systems has been studied by the thermally stimulated depolarization current (TSDC) method in the temperature range 80-300 K. Two different buffer solutions were used, namely 10(-3) M tris buffer and 1 x ssc, while the DNA concentration in the solutions varied between 0.1% and 2%. Addition of DNA in the buffer solution up to a certain level results in DNA-buffer binding with consequent release of bound water molecules, and the first hydration layer seems to remain unfrozen at temperatures as low as -100-degrees-C, in accordance with results obtained with quite different techniques by other authors.