Analysis of the inactivation mechanism of bacteriophage by Atmospheric barrier discharge

The inactivation mechanism of virus and bacteria by atmospheric discharge plasma has been studied actively. However, predominant factors in the inactivation are not clear at all. Because the atmospheric discharge plasma includes a lot of possible inactivation factors such as active oxygen species, ozone and ultraviolet rays, it is difficult to analyze each effect separately. In this study, bacteriophage lambda was used as the simplest model biological samples to analyze the inactivation mechanism by atmospheric discharge plasma. When bacteriophage having only DNA and coat proteins is inactivated by DBD, damage should exist on DNA or coat proteins. In the experiment using bacteriophage, it is able to extract DNA from the bacteriophage so that the damaged coat proteins can be removed to avoid the effect of the proteins. And, DNA which is extracted from plasma-inactivated phage can be assayed its plaque forming activity. Using this assay, the damages on DNA and coat proteins have been determined separately. The results show that inactivation of lambda phage by atmospheric DBD was attributed to the damage mainly of coat protein. The damage of lambda DNA was negligible in the early stage of the inactivation. Key word—Non-thermal plasma, Plasma sterilization, Virus, Bacteriophage