Study on the antifungal effect of atmospheric-pressure microplasma excited by high-repetition-rate inductive energy storage

Abstract

Atmospheric microplasma in a plane-parallel configuration was excited by high-repetition-rate inductive energy storage. We studied (1) the homogeneity of the microplasma device and (2) the inactivation efficacy for Aspergillus brasiliensis ATCC 9642 and Aspergillus niger NBRC 6341 when exposed to microplasma. Filamentary images during breakdown and afterglow were captured using a high-performance intensified CCD camera. Microorganisms of different species, Aspergillus brasiliensis ATCC 9642 and Aspergillus niger NBRC 6341, were used as biological indicators. Our work recorded inactivation time as a function of gas mixture. These experimental results suggest microplasma can strongly enhance antibiotic effects through UV radiation, a high electric field, and plasma radicals. Our experimental results have shown that plasma with a higher nitrogen ratio and a small percentage of oxygen has better inactivation properties for microorganisms with high UV tolerance. The small percentage of oxygen is needed for the excitation process and oxidation.