Physicochemical processes in the indirect interaction between surface air plasma and deionized water

Guo

Plasma Processes & Polymers

et al. 2016

Normal saline is a common biological solution which provides much better living environment for Staphylococcus aureus than deionized water, but the plasma‐activated normal saline is found to have a stronger bactericidal effect than the plasma‐activated deionized water. A model is developed for the explanation, from which various kinds of reactive chlorine/oxy‐chlorine species (RCS), such as HClO, are found to be generated in the plasma‐activated normal saline. The production pathways of RCS are elucidated, in which O3 plays as an important intermediate species. Compared to the plasma‐activated deionized water, the concentrations of reactive oxygen/nitrogen species are lower, but the bactericidal effect is higher, implying that the RCS play a crucial role for the sterilization.

Section: Experimental Setup and Its Bactericidal Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemical Kinetics and Reactive Species in Normal Saline Activated by a Surface Air Discharge

Guo

Plasma Processes & Polymers

et al. 2016

“…When plasma is in contact with water, the plasma-water interactions can entail many direct reactions at the plasma-water interface and indirect cascade reactions in the bulk water202122232425. One important species at the plasma-water interface is hydroxyl radical (OH) produced by plasma-induced water reactions with electrons and ions.…”

mentioning

confidence: 99%

Direct synthesis of hydrogen peroxide from plasma-water interactions

Chen

et al. 2016

Sci Rep

Hydrogen peroxide (H2O2) is usually considered to be an important reagent in green chemistry since water is the only by-product in H2O2 involved oxidation reactions. Early studies show that direct synthesis of H2O2 by plasma-water interactions is possible, while the factors affecting the H2O2 production in this method remain unclear. Herein, we present a study on the H2O2 synthesis by atmospheric pressure plasma-water interactions. The results indicate that the most important factors for the H2O2 production are the processes taking place at the plasma-water interface, including sputtering, electric field induced hydrated ion emission, and evaporation. The H2O2 production rate reaches ~1200 μmol/h when the liquid cathode is purified water or an aqueous solution of NaCl with an initial conductivity of 10500 μS cm−1.

“…The predominant mechanism by which CAP brings about microbial inactivation is through the generation of both reactive oxygen species (ROS) and reactive nitrogen species (RNS), including O 3 (37). The ocular pathogens investigated here included the protozoans A. polyphaga and A. castellanii, the bacterium P. aeruginosa, and the yeast C. albicans.…”

Section: Discussionmentioning

confidence: 99%

“…With the ground electrode facing the microbial sample (described below), the electrode unit was suspended above the sample as shown in Fig. 1 (37).…”

Section: Chemicalsmentioning

confidence: 99%

Inactivation of Acanthamoeba spp. and Other Ocular Pathogens by Application of Cold Atmospheric Gas Plasma

Heaselgrave

Shama

Andrew

et al. 2016

Appl Environ Microbiol

dCurrently there are estimated to be approximately 3.7 million contact lens wearers in the United Kingdom and 39.2 million in North America. Contact lens wear is a major risk factor for developing an infection of the cornea known as keratitis due to poor lens hygiene practices. While there is an international standard for testing disinfection methods against bacteria and fungi (ISO 14729), no such guidelines exist for the protozoan Acanthamoeba, which causes a potentially blinding keratitis most commonly seen in contact lens wearers, and as a result, many commercially available disinfecting solutions show incomplete disinfection after 6 and 24 h of exposure. Challenge test assays based on international standard ISO 14729 were used to determine the antimicrobial activity of cold atmospheric gas plasma (CAP) against Pseudomonas aeruginosa, Candida albicans, and trophozoites and cysts of Acanthamoeba polyphaga and Acanthamoeba castellanii. P. aeruginosa and C. albicans were completely inactivated in 0.5 min and 2 min, respectively, and trophozoites of A. polyphaga and A. castellanii were completely inactivated in 1 min and 2 min, respectively. Furthermore, for the highly resistant cyst stage of both species, complete inactivation was achieved after 4 min of exposure to CAP. This study demonstrates that the CAP technology is highly effective against bacterial, fungal, and protozoan pathogens. The further development of this technology has enormous potential, as this approach is able to deliver the complete inactivation of ocular pathogens in minutes, in contrast to commercial multipurpose disinfecting solutions that require a minimum of 6 h.