Dielectric barrier atmospheric discharge combined with petri-dish

Summary form only given. A plasma generating apparatus of a low-frequency dielectric barrier discharge (DBD) is designed and applied to treating microorganisms. Biomedical plasma applications have been extensively developed with plasma jets, such as pencil-type in which the gas is injected at the flow rate of a several liters per minutes. However, the gas flow from the nozzle of plasma jet may affect a microbial sample by blowing it in the incubator. Avoiding the blowing out the sample materials on the plate, a plasma jet device generating plasma without injecting the gas is designed. By direct air-discharge in the atmosphere environment of incubator without gas flow, it is effective to investigate the reaction of plasma with the microorganisms. Because the propagation distance of plasma is short due to the short life time of plasma, the Petri-dish and DBD system are combined to generate the DBD plasma in the incubator. Using the plasma device designed in this study, we tried to examine the bacterial responses to the plasma and the effect of electric field caused by the plasma on bacteria. In the experiments, bacteria (Escherichia coli) and a fungus (Fusarium graminearum) were treated with the plasma in the different distance, the treating time, and the area of electrode. For the uniform plasma, the various structures of a capillary or the multi-pin electrode are investigated with respect to the firing voltage and the operation frequency.