Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Decomposition of Biological Macromolecules by Plasma Generated with Helium and Oxygen: Seong-Mi Kim , Jong-Il Kim; J. Microbiol. 2006;44(4):466-471.; DOI: https://doi.org/2403 [pii]

Abstract: In this study, we attempted to characterize the biomolecular effects of an atmospheric pressure cold plasma (APCP) system which utilizes helium/oxygen (He/O2). APCP using He/O2 generates a low level of UV while generating reactive oxygen radicals which probably serve as the primary factor in sterilization; these reactive oxygen radicals have the advantage of being capable to access the interiors of the structures of microbial cells. The damaging effects of plasma exposure on polypeptides, DNA, and enzyme proteins in the cell were assessed usiing biochemical methods.

Sterilization of Bacteria, Yeast, and Bacterial Endospores by Atmospheric-Pressure Cold Plasma using Helium and Oxygen: Kyenam Lee , Kwang-hyun Paek , Won-Tae Ju , Yoenhee Lee; J. Microbiol. 2006;44(3):269-275.; DOI: https://doi.org/2386 [pii]

Abstract: Atmospheric-pressure cold plasma (APCP) using helium/oxygen was developed and tested as a suitable sterilization method in a clinical environment. The sterilizing effect of this method is not due to UV light, which is known to be the major sterilization factor of APCP, but instead results from the action of reactive oxygen radicals. Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae deposited on a nitrocellulose filter membrane or Bacillus subtilis spores deposited on polypropylene plates were exposed to helium/oxygen plasma generated with AC input power at 10 kHz, 6 kV. After plasma treatment, nitrocellulose filter membranes were overlaid on fresh solid media and CFUs were counted after incubation overnight. D-values were 18 sec for E. coli, 19 sec for S. aureus, 1 min 55 sec for S. cerevisiae, and 14 min for B. subtilis spores. D-values of bacteria and yeast were dependent on the initial inoculation concentration, while the D-value of B. subtilis spores showed no correlation. When treated cells were observed with a scanning electron microscope, E. coli was more heavily damaged than S. aureus, S. cerevisiae exhibited peeling, and B. subtilis spores exhibited shrunken morphology. Results showed that APCP using helium/oxygen has many advantages as a sterilization method, especially in a clinical environment with conditions such as stable temperature, unlimited sample size, and no harmful gas production.

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