Abstract
Here we present the results of an experimental study of the effect of ions produced in a dc corona discharge on inactivation of bacteria on the surface of agarose gel. Both positive and negative corona discharges in various gases at different humidities were studied. The measurements in air, O2, N2, Ar and He mixtures show that there is no inactivation in pure N2, pure O2 and an N2–H2O mixture. The best results were achieved in the case of direct treatment, when discharge was ignited in oxygen and water-containing mixtures. We show that neither UV radiation, ozone or H2O2 nor other neutral active species alone produced by corona have an effect on bacteria viability. It is shown that the main role of charged particles may be related to the faster transport of active peroxide species—cluster ions OH−(H2O)n and H3O+(H2O)n. The efficiency of these radicals is much higher than that of the oxygen radicals and ions (including O−2, O+4 and O3) and that of nitrogen and argon ions.
Highlights
Plasma inactivation of bacteria is one of the first demonstrations of biomedical applications of plasmas
Initial experiments were performed with bacteria of various initial concentrations dried on agar (‘moist’ condition) utilizing corona discharge in room air (~60% humidity) with a constant current of 100 μA
The resulting numbers of colonies on the treated area after incubation were recalculated to a number of colony-forming units (CFU) per cm2 assuming that the area of treatment was about 19.5 cm2
Summary
Plasma inactivation of bacteria is one of the first demonstrations of biomedical applications of plasmas. The nature of plasma interactions with bacteria is rather complex, and is clearly different for different conditions, e.g. arc discharge at atmospheric pressure and lowpressure glow discharge [7, 16, 17, 19]. In the frame of a new and actively growing field of plasma chemistry, plasma medicine, understanding the mechanisms of interaction of nonthermal atmospheric pressure discharges with living objects becomes extremely important. We have focused on the investigation of role of the different components of corona discharge plasma in the process of bacteria inactivation on the surface
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
