Evaluation of DNA Damage Using Microwave Dielectric Absorption Spectroscopy

Abstract

Background: Evaluation of deoxyribonucleic acid (DNA)-strand break is important to elucidate the biological effect of ionizing radiations. The conventional methods for DNA-strand break evaluation have been achieved by Agarose gel electrophoresis and others using an electrical property of DNAs. Such kinds of DNA-strand break evaluation systems can estimate DNAstrand break, according to a molecular weight of DNAs. However, the conventional method needs pre-treatment of the sample and a relatively long period for analysis. They do not have enough sensitivity to detect the strand break products in the low-dose region. Materials and Methods: The sample is water, methanol and plasmid DNA solution. The plasmid DNA pUC118 was multiplied by using Escherichia coli JM109 competent cells. The resonance frequency and Q-value were measured by means of microwave dielectric absorption spectroscopy. When a sample is located at a center of the electric field, resonance curve of the frequency that existed as a standing wave is disturbed. As a result, the perturbation effect to perform a resonance with different frequency is adopted. Results and Discussion: The resonance frequency shifted to higher frequency with an increase in a concentration of methanol as the model of the biological material, and the Q-value decreased. The absorption peak in microwave power spectrum of the double-strand break plasmid DNA shifted from the non-damaged plasmid DNA. Moreover, the sharpness of absorption peak changed resulting in change in Q-value. We confirmed that a resonance frequency shifted to higher frequency with an increase in concentration of the plasmid DNA. Conclusion: We developed a new technique for an evaluation of DNA damage. In this paper, we report the evaluation method of DNA damage using microwave dielectric absorption spectroscopy.

Microwave Dielectric Absorption Spectroscopy Aiming at Novel Dosimetry Using DNAs

“…Therefore the reliability of this system was increased. The results of experiments with DNAs were reported in elsewhere [5]. We have made great effort to reduce the influences by conditions such as temperature and humidity.…”

Broadband Dielectric Spectroscopy as a Potential Label-Free Method to Rapidly Verify Ultraviolet-C Radiation Disinfection

“…For most cells, the total dielectric constant of solutions declines linearly in proportion with the volume fraction (P) of intact cells up to the limits of 10% to 20% [ 8 , 15 ]. MW signal loss in heterogeneous thin films, however, is more complicated and exhibits nonideal behavior because of the additional collective loss modes and small amounts of water content [ 15 , 16 ]. Thus, the observed dielectric loss and the derived electrical resistance in thin films of biological samples represent the “effective” resistance of the entire film and may not be specific to a single species.…”