Plasma Treatment of Liquids

Ng, Sing Wei; Tsoukou, Evanthia; Chaple, Sonal; Boehm, Daniela; Bourke, Paula

doi:10.1016/b978-0-12-815781-7.00003-2

Cited by 4 publications

(2 citation statements)

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“…The efficacy of each PAL depends on the reactive species produced in the PAL, the type of microorganism and phenotype [14]. PAL generated at atmospheric pressure will generally contain aqueous reactive species such as hydrogen peroxide, nitrite and nitrate ions, acidic pH values and a high oxidation reduction potential which may play a crucial role in the microbial inactivation potential of plasma activated water (PAW) [3,15].…”

Section: Introductionmentioning

confidence: 99%

Distinct Chemistries Define the Diverse Biological Effects of Plasma Activated Water Generated with Spark and Glow Plasma Discharges

et al. 2021

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The spread of multidrug-resistant bacteria poses a significant threat to human health. Plasma activated liquids (PAL) could be a promising alternative for microbial decontamination, where different PAL can possess diverse antimicrobial efficacies and cytotoxic profiles, depending on the range and concentration of their reactive chemical species. In this research, the biological activity of plasma activated water (PAW) on different biological targets including both microbiological and mammalian cells was investigated in vitro. The aim was to further an understanding of the specific role of distinct plasma reactive species, which is required to tailor plasma activated liquids for use in applications where high antimicrobial activity is required without adversely affecting the biology of eukaryotic cells. PAW was generated by glow and spark discharges, which provide selective generation of hydrogen peroxide, nitrite and nitrate in the liquid. The PAW made by either spark or glow discharges showed similar antimicrobial efficacy and stability of activity, despite the very different reactive oxygen species (ROS) and reactive nitrogen species profiles (RNS). However, different trends were observed for cytotoxic activities and effects on enzyme function, which were translated through the selective chemical species generation. These findings indicate very distinct mechanisms of action which may be exploited when tailoring plasma activated liquids to various applications. A remarkable stability to heat and pressure was noted for PAW generated with this set up, which broadens the application potential. These features also suggest that post plasma modifications and post generation stability can be harnessed as a further means of modulating the chemistry, activity and mode of delivery of plasma functionalised liquids. Overall, these results further understanding on how PAL generation may be tuned to provide candidate disinfectant agents for biomedical application or for bio-decontamination in diverse areas.

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Section: Introductionmentioning

confidence: 99%

Distinct Chemistries Define the Diverse Biological Effects of Plasma Activated Water Generated with Spark and Glow Plasma Discharges

et al. 2021

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“…PAL are usually generated by atmospheric cold plasma discharges directly within the liquids, discharges in the gas phase over the liquid surface and multiphase discharges 16 . Changes in the physicochemical properties of PAL depend on plasma treatment time, working gas, nature of solution and plasma device 17 . Exposure of liquids to cold plasma result in aqueous solutions which consist of relatively long-lived reactive oxygen and nitrogen species such as hydrogen peroxide, nitrites, nitrates 12 and other short lived chemical species such as nitric oxide, hydroxyl radicals, superoxide, peroxynitrate, and peroxynitrite 18 .…”

Section: Introductionmentioning

confidence: 99%

Efficacy of plasma activated saline in a co-culture infection control model

Tsoukou

Bourke

Boehm

2022

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Plasma activated liquids have demonstrated antimicrobial effects and receive increasing attention due to the potential to strengthen the armoury of novel approaches against antibiotic resistant bacteria. However, the antibacterial activity and cytotoxic effects of these solutions need to be understood and balanced before exposure to humans. In this study, the antibacterial effects of plasma activated saline (PAS) were tested against Gram negative and positive bacteria, and HaCaT keratinocytes were used for cytotoxicity studies. For the first time, a co-culture model between these bacteria and eukaryotic cells under the influence of PAS has been described. Exposure of saline to plasma resulted in high concentrations of nitrate, hydrogen peroxide and a reduction of pH. PAS caused high antibacterial effects in the co-culture model, accompanied by high cytotoxic effects to the monolayer of mammalian cells. We present evidence and provide a deeper understanding for the hypothesis that upon treatment with PAS, chemical species generated in the liquid mediate high antimicrobial effects in the co-culture setup as well as mitochondrial depolarization and glutathione depletion in HaCaT cells and cell lysis due to acidic pH. In conclusion, PAS retains strong antibacterial effects in a co-culture model, which may have unintended negative biological effects on mammalian cells.

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