Analysis of DNA strand breaks induced by exposure to an atmospheric pressure plasma jet

Recent progress of biomedical application of non-thermal plasmas shows that the biological effects are mainly due to oxidative reactions induced by reactive oxygen and nitrogen species produced by exposure to the plasma. Therefore, a rapid and quantitative evaluation method for damage of biomacromolecules induced by exposure to the plasma is required. DNA is one of the most important biomolecular targets for investigating the effects of exposure to the plasma. It has been reported that DNA strand breaks are induced when DNA is exposed to an atmospheric non-thermal plasma. We previously reported a single-molecule-based method for evaluating strand breaks in large linear DNA molecules that allows the length of individual DNA molecules to be measured1. However, a rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is currently challenging. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma2.