Development of a DNA Biodosimeter for UV Radiation

Abstract

Ultraviolet (UV) radiation has a strong influence in the damage of deoxyribonucleic acid (DNA). In this work, the possibility of a DNA UV radiation dosimeter is evaluated. For that, calf thymus DNA samples, thin films and aqueous solutions, were irradiated with 254 nm wavelength light during different periods of time, being the damage caused by the irradiation analysed by both UV-visible and infrared spectroscopies. As the DNA is a polyelectrolyte, the pH of the DNA samples was also considered as a variable. Results demonstrated that damage in DNA takes place in both thin films and solutions when irradiated at 254 nm, as revealed by a consistent decay in measured absorbance values. However, DNA solutions were seen to give more reliable as the induced damage is easily measured. For this case, the absorbance at 260 nm was seen to exponentially decrease with the irradiation time as a result of radiation damage with the kinetics damage strongly dependent of pH. Consequently, the lifetime of such dosimeter device can be chosen by changing the pH of aqueous solutions.