DocumentCode :
1303240
Title :
Cold DC-Operated Air Plasma Jet for the Inactivation of Infectious Microorganisms
Author :
Kolb, Juergen F. ; Mattson, Amber M. ; Edelblute, Chelsea M. ; Hao, Xiaolong ; Malik, Muhammad Arif ; Heller, Loree C.
Author_Institution :
Frank Reidy Res. Center for Bioelectrics, Old Dominion Univ., Norfolk, VA, USA
Volume :
40
Issue :
11
fYear :
2012
Firstpage :
3007
Lastpage :
3026
Abstract :
We evaluated a nonthermal plasma jet for a respective use to prevent infections from bacteria and yeasts. The plasma jet is generated from the flow of ambient air with 8 slm through a microhollow cathode discharge assembly that is operated with a direct current of 30 mA. With these parameters, the temperature in the jet reaches 43 °C at 10 mm from the discharge. Agar plates that were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Candida kefyr were treated at this distance, moving the plates through the jet in a meander that covered a 2 cm by 2 cm area. Different exposure times were realized by changing the speed of the movement and adjusting the distance between consecutive passes. S. aureus was most responsive to the exposure with a reduction in the number of colony forming units of 5.5 log steps in 40 s. All other microorganisms show a more gradual inactivation with exposure times. For all bacteria, a clearing of the treated area is achieved in about 2.5-3.5 min, corresponding to log-reduction factors of 5.5-6.5. Complete inactivation of the yeast requires about 7 min. Both S. aureus and C. kefyr show considerable inactivation also outside the immediate treatment area, while P. aeruginosa and A. baumannii do not. We conclude that differences in the morphologies of the membrane structures are responsible for the diverging results, together with a targeted response to different agents provided with the plasma jet. For the gram negative bacteria, we hold short-lived agents, acting across a short range, responsible, while for the other microorganisms, longer lived species seem more important. Our measurements show that neither heat, ultraviolet radiation, nor the generation of ozone can be responsible for the observed results. The most prominent long lived reaction product found is nitric oxide, which, by itself or through induced chemical reactions, might affect cell viability.
Keywords :
antibacterial activity; biomembranes; cellular biophysics; discharges (electric); microorganisms; plasma applications; plasma jets; Acinetobacter baumannii; Candida kefyr; Pseudomonas aeruginosa; Staphylococcus aureus; agar plates; cell viability; chemical reactions; cold DC-operated air plasma jet; current 30 mA; distance 10 mm; gram negative bacteria; heat; infections; infectious microorganisms inactivation; long lived reaction product; membrane structures; microhollow cathode discharge assembly; nitric oxide; nonthermal plasma jet; ozone generation; size 2 cm; temperature 43 C; time 40 s; ultraviolet radiation; yeasts; Discharges (electric); Electrodes; Electron tubes; Microorganisms; Plasma temperature; Wounds; Nonthermal plasma; plasma medicine; skin disinfection; wound healing;
fLanguage :
English
Journal_Title :
Plasma Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0093-3813
Type :
jour
DOI :
10.1109/TPS.2012.2216292
Filename :
6316183
Link To Document :
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