Effects of oxygen radicals in low-pressure surface-wave plasma on sterilization

Nagatsu, Masaaki; Terashita, Fumie; Nonaka, Hiroyuki; Xu, Lei; Nagata, Toshi; Koide, Yukio
May 2005
Applied Physics Letters;5/23/2005, Vol. 86 Issue 21, p211502
Academic Journal
The effects of oxygen radicals on sterilization were studied using a 2.45 GHz surface-wave oxygen plasma. A population of 1.5×106 Bacillus stearothermophilus spores was irradiated for 3 min or more with oxygen plasma, generated at pressures between 6 and 14 Pa. The decimal reduction value (D value), a measure of the effectiveness of sterilization, was determined to be about 15–25 s. Using only oxygen radicals, excluding all charged particles, the 1.5×106 spores were sterilized with a D value of 30–45 s after 5 min or more of irradiation. On scanning electron microscopy, the length and width of the spores changed significantly due to chemical etching by oxygen radicals.


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