The bactericidal efficacy of cold atmospheric plasma technology on some bacterial strains

Abstract

Plasma, a mix of ionized gas molecules and free electrons, is often referred to as the fourth state of matter. There are different applications of plasma in our life starts from easy lighting to disease fighting and it's nothing new. Fluorescent lights, air conditions and plasma televisions use it. One of its different types is atmospheric cold plasma, the possible applications for sterilization using cold plasmas range from the food industry to planetary space missions. The same technique could also be used on space craft leaving Earth to avoid transporting microorganisms from Earth to other planets or moons. The use of toxic chemicals to sterilize medical instruments may soon be a thing of the past because the use of cold plasma to sterilize heat-sensitive reusable medical tools in a rapid, safe, and effective way is bound to replace the present method which uses a toxic gas as ethylene oxide, in addition to its use for air purification. Lately it is tested to prepare surfaces for bonding and kill bacteria on delicate living tissues. We report the results of an interdisciplinary collaboration formed to assess the sterilizing capabilities of the cold atmospheric plasma. This newly-invented source of plasma is capable of operating at atmospheric pressure in air and other gases, and of providing antimicrobial activity at room temperature as judged by viable plate counts. Plasma exposures have reduced log numbers of three tested bacterial strains namely, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa seeded on solid surfaces of Muller-Hinton agar at room temperature. Initial experimental data showed ≥5 log 10 CFU reduction of bacteria when 5×10 6 cfu.ml-1 of samples seeded on MHA plates. Results showed >5 log 10 CFU reduction with E. coli when exposed for up to 360 sec to plasma while the same exposure time was required for 5 log 10 CFU reduction killing with S. aureus samples, the least affected by this treatment was Pseudomonas aeruginosa cell suspensions where there was a very few reduction in number of survivals (≤ 10% of the whole population) after the same exposure time application. For all microorganisms tested, a biphasic curve was generated when the number of survivors versus time was plotted in dose-response curves. In conclusion we can report that the atmospheric cold plasma generated by this method has proven sterilization (kill) capability against both gram-positive and gramnegative bacteria in different extents depending on special strain characteristics.

Non-thermal gas plasma-induced endoplasmic reticulum stress mediates apoptosis in human colon cancer cells

“…Therefore, novel non-chemical strategies for treating colorectal cancer are urgently needed. NTGP has been characterized in various clinical applications as a promising tool for wound healing (27), plasma sterilization (28), blood coagulation (29), cell detachment (30), induction of apoptosis (31), and cancer therapy (32). Therefore, we investigated whether NTGP induces apoptosis in SNUC5 human colon carcinoma cells by generating ER stress.…”

Effects and Mechanism of Atmospheric-Pressure Dielectric Barrier Discharge Cold Plasmaon Lactate Dehydrogenase (LDH) Enzyme

“…Owing to advantages such as production of highly reactive species at low temperature and flexible operation 1 2 , atmospheric-pressure non-thermal plasmas have attracted much attention in biology and biomedicine 3 and applications include plasma sterilization 4 5 6 7 8 9 10 11 , living tissue treatment 12 , blood coagulation 13 , cell detachment 14 15 , induction of apoptosis 16 17 18 , cell proliferation 19 , cancer therapy 20 21 22 23 24 , and so on. However, even though the biological effects of atmospheric-pressure plasmas have been investigated and several possible mechanisms have been suggested, systematic verification of these hypotheses is still lacking and the precise mechanism is still not well understood.…”

Enhancement of seed germination and microbial disinfection on ginseng by cold plasma treatment

“…The results of these studies are in accordance with our results, where the fungicidal effect of plasma was observed to be greater than its bactericidal effect, even though, the fungal cell wall is constituted of chitin and pigments such as melanins [ 47 ], which may provide protection against damaging agents, including gamma irradiation, extreme temperatures, and free oxygen radicals [ 48 ]. A previous study by Moman et al [ 49 ] reported a similar effect of plasma treatment on Pseudomonas spp., which are widespread bacteria in agricultural soils and have both beneficial and harmful effects on plants [ 50 ]. The findings in our study underlie the hypothesis that the exposure of cold plasma may associate with the decontamination of surface pathogens on ginseng seeds, which depends on characteristics of target microorganism.…”