Potential Enhancement of Microbial Disinfection Using Oxygen Enriched Cold Atmospheric-pressure Argon (Ar/O) Plasma Jet

Oxygen activated cold-atmospheric-pressure-argon plasma jet (APPJ) has gained prominence over the regular argon plasma especially in disinfection and decontamination. As an objective of the current research, an oxygen-enriched argon system was built, where plasma produced through a vessel metallic tube that is introduced into alumina one. A sinusoidal high voltage signal of 25 kHz was used to generate plasma jet. Potential impact of oxygen enriched APP jet (Ar/O) in decontamination of different microbial cells was observed. For examination, suspension of each tested microbe was placed in contact with plasma jet nearly 10 mm away from the jet nozzle and the lethal effect of activated plasma was evaluated. Results showed that the Ar/O -APP plasma enhanced reactive hydroxyl and other reactive oxygen species generation and hence, antimicrobial activities. For Escherichia coli cells approximately 96.27% and 90.50% reduction in living cell count were recorded after 30 s of exposure to oxygen-activated plasma, on water and LB medium, with a D-value of 36.21 s and 588.24 s, respectively. Also, reduction in Staphylococcus aureus cells was 92.8% and 96.6% after 30 s, with the D-values of 33.9 s and 181.8 s in water and LB media, respectively. Moreover, Candida albicans fungal cells revealed 95% reduction in viable cell count after 10 s. However, the D-value showed only 6.3 s increase due to the impact of organic materials as a component of LB nutritive medium. Generally, the activated argon plasma works effectively even in the presence of organic debris in an exposed medium. Therefore, APPJ can be considered as a prominent straightforward technology for medication of diseases caused by antimicrobial drug-resistant pathogens.