Effects of humidity on sterilization of<i>Geobacillus stearothermophilus</i>spores with plasma-excited neutral gas

Matsui, Kei; Ikenaga, Noriaki; Sakudo, N.

doi:10.7567/jjap.54.06gd02

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…The increase in humidity can accelerate the generation of OH, H 2 O 2 , HO 2 , and HNO 2 in gas-phase plasma [7]. Similar phenomena have been observed in other DBD reactors, where the concentrations of NO and NO 2 were found to increase with increasing humidity in the air plasma [50]. On the other hand, an increase in humidity can decrease the rate constants associated with electrons and have an effect on electron transport properties [51].…”

Section: Discussionsupporting

confidence: 74%

E. Coli inactivation by humidified air barrier discharge plasmas and the chemical stability of amino acids

Wang,

Liang,

Dou

et al. 2024

J. Phys. D: Appl. Phys.

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In this study, we use atmospheric air dielectric barrier discharge (DBD) plasma to inactivate Escherichia coli (E. coli) by changing the air humidity levels. In order to analyze the inactivation process of E. coli during the humidified air DBD plasma treatment, we analyze the byproducts of 12 representational amino acids and compare their chemical stability. The experimental results show that the E. coli surface density (CFU/cm2) on a steel disc decreased significantly when the air humidity was increased from 20% to 60%, and humidified air DBD plasma at 60% humidity is very effective in inactivating E. coli. A consistently potent deactivation effect on E. coli can be seen in plasma afterglow treatment experiments over a storage time of two minutes, indicating that plasma-activated long-lived reactive oxygen and nitrogen species play a crucial role in controlling the E. coli inactivation. Compared to the low humidity (20%) condition, the concentration of reactive species produced by the plasma at high humidity (60%) increased 2-fold for 2-hydroxyterephthalic acid and 5-fold for hydrogen peroxide while ozone production was halved. Amino acid experiments showed that amino acids may be oxidized, hydroxylated and nitroxylated by reactive species. The reduction of amino acids by air DBD plasma was even more pronounced at high air humidity compared to low air humidity. Our analysis indicates that the significant inactivation of E. coli by humified air DBD plasma is related to the chemical instability of amino acids.

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Section: Discussionsupporting

confidence: 74%

E. Coli inactivation by humidified air barrier discharge plasmas and the chemical stability of amino acids

Wang,

Liang,

Dou

et al. 2024

J. Phys. D: Appl. Phys.

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“…The atmospheric pressure plasma can produce chemically reactive atoms and molecules, called reactive oxygen species (ROS) and reactive nitrogen species (RNS). The RONS (ROS and RNS) are important in living organisms [2,[7][8] and reported to play major roles on the plasma sterilization [9][10][11][12][13][14][15][16][17][18][19][20][21] . The correlation between the plasma produced RONS and the antibacterial effect has been discussed, such as oxygen atom [9] , hydroxyl radical [10] , ozone (O 3gas /O 3aq ) [9][10][11] , peroxynitrites (HOONO aq /ONOOaq ) [12][13][14][15] , hydroperoxy radical [16] , and hydrogen peroxide (H 2 O 2aq ) [17] , measured in the gas phase [9][10][11] and/or in the liquid phase [12][13][14][15][16][17][18][19][20][21] .…”

Section: Introductionmentioning

confidence: 99%

Humidification effect of air plasma effluent gas on suppressing conidium germination of a plant pathogenic fungus in the liquid phase

Shimada

Takashima

Kimura

et al. 2019

Plasma Processes & Polymers

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Increase of the water flow rate into atmospheric pressure air discharge plasma for humidification can significantly improve in suppressing conidium germination of a plant pathogenic fungus in the liquid phase by its effluent gas exposure. The roles of the introduced water are enhancement of hydrogen supply to the plasma and cooling of the plasma effluent gas. The hydrogen-containing precursors for antibacterial species generation are experimentally increased. The gas cooling by the latent heat a (Keisuke Shimada and Keisuke Takashima contributed equally to this work.) This is the author manuscript accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

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“…1) Plasma sterilization can be carried out at low temperatures without residual remaining toxic gases and is ideal for medical instruments. Studies on sterilization using lowpressure discharge plasma [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and atmospheric pressure discharge plasma [18][19][20][21][22][23][24][25][26][27][28][29][30] have been actively conducted.…”

Section: Introductionmentioning

confidence: 99%

Sterilization characteristics of dental instruments using oxygen plasma produced by narrow gap RF discharge

Sakai

Liu

Goto

et al. 2016

Jpn. J. Appl. Phys.

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Sterilization characteristics and material compatibility of low-pressure RF oxygen plasma sterilization method for dental instruments are investigated. Regarding the characteristics of the plasma sterilizer for dental instruments, it is small and can rapidly sterilize owing to a narrow gap discharge. Sterilization of vial-type biological indicators is achieved for the shortest treatment period of 40 min at an RF power of 80 W at a temperature of 70 °C. At a temperature lower than 60 °C, a sterilization period of 90 min is required using a water-cooled electrode. No surface modifications of dental instruments such as chemical composition and deterioration of fine crystals of a diamond bar were observed under a scanning electron microscope.

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Effects of humidity on sterilization ofGeobacillus stearothermophilusspores with plasma-excited neutral gas

Cited by 5 publications

References 34 publications

E. Coli inactivation by humidified air barrier discharge plasmas and the chemical stability of amino acids

E. Coli inactivation by humidified air barrier discharge plasmas and the chemical stability of amino acids

Humidification effect of air plasma effluent gas on suppressing conidium germination of a plant pathogenic fungus in the liquid phase

Sterilization characteristics of dental instruments using oxygen plasma produced by narrow gap RF discharge

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