Disinfection of Ocular Cells and Tissues by Atmospheric-Pressure Cold Plasma

Brun, Paola; Vono, Maria; Venier, Paola; Tarricone, Elena; Deligianni, Velika; Martines, E.; Zuin, M.; Spagnolo, S.; Cavazzana, R.; Cardin, Romilda; Castagliuolo, Ignazio; Valerio, Alvise La Gloria; Leonardi, Andrea

doi:10.1371/journal.pone.0033245

Cited by 109 publications

(128 citation statements)

References 45 publications

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“…The amount of reactive species generated, including ozone, has been correlated with inactivation efficacy (12,36,(39)(40)(41). Among the reactive species generated during HVACP treatment, ROS contributed as major antimicrobial factors.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus

Han¹,

Patil²,

Boehm³

et al. 2016

Appl Environ Microbiol

327

200

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bAtmospheric cold plasma (ACP) is a promising nonthermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen-containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation, and DNA cleavage. Identification of ROS and an understanding of their role are important for advancing ACP applications for a range of complex microbiological issues. In this study, the inactivation efficacy of in-package high-voltage (80 kV [root mean square]) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed in which reactive species were found to either react primarily with the cell envelope or damage intracellular components. Escherichia coli was inactivated mainly by cell leakage and low-level DNA damage. Conversely, Staphylococcus aureus was mainly inactivated by intracellular damage, with significantly higher levels of intracellular ROS observed and little envelope damage. However, for both bacteria studied, increasing treatment time had a positive effect on the intracellular ROS levels generated.A tmospheric cold plasma (ACP) refers to nonequilibrated plasma generated at near-ambient temperatures and pressure. ACP is composed of particles, including free electrons, radicals, and positive and negative ions, but it is low in collision frequency of gas discharge compared to that with equilibrated plasma (1, 2). ACP technologies have widely been applied for many surface treatments and environmental processes. Recently, they have been studied for food sterilization and plasma medicine (2-5).ACP provides inactivation effects against a wide range of microbes, mainly by the generation of cell-lethal reactive species (6-8). By discharging in air, groups of reactive species are generated, such as reactive oxygen species (ROS), reactive nitrogen species (RNS), UV radiation, energetic ions, and charged particles (5). However, the inactivation efficacy can be varied by changing the working gases, which results in different types or amounts of reactive species generated (9-11). ROS are often identified as the principal effecting species, with a relatively long half-life and strong antimicrobial effects, which are generated in oxygen-containing gases (12).ROS generated during plasma discharge in air or oxygen-containing mixtures are assemblies of ozone, hydrogen peroxide, and singlet and atomic oxygen, while ozone is considered the most microbicidal species (13). With strong oxidative stress, cells are damaged by lipid peroxidation, enzyme inactivation, and DNA cleavage. The generation of plasma in air or a nitrogen-containing gas mixture can also generate NO x species. However, higher inactivation efficacy has been reported with the combined application of NO and H 2 O 2 on Escherichia coli than that with a treatment with NO or H 2 O 2 alone (14). Reactive nitrogen species are highly toxic and can lead to cell death by increas...

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Section: Discussionmentioning

confidence: 99%

Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus

Han¹,

Patil²,

Boehm³

et al. 2016

Appl Environ Microbiol

327

200

View full text Add to dashboard Cite

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“…Cold or nonthermal plasma has been actively deployed for practical purposes [7], and nonequilibrium atmospheric pressure plasma (NEAPP) therapy is currently hoped to fulfill new roles in the field of medical science [8][9][10]. In recent years, several therapeutic trials have been completed in the fields of tissue sterilization, blood coagulation, wound-healing promotion, and dental bleaching [11][12][13]. Additionally, it has been reported that plasma can exert antiproliferative effects on various cancer cell lines, possibly through induction of apoptosis [6,14,15].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of plasma treatment on gastric cancer cells

et al. 2014

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Background Treatment of peritoneal carcinomatosis arising from gastric cancer remains a considerable challenge. In recent years, the anticancer effect of nonequilibrium atmospheric pressure plasma (NEAPP) has been reported in several cancer cell lines. Use of NEAPP may develop into a new class of anticancer therapy that augments surgery, chemotherapy, and radiotherapy. Method Gastric cancer cells were assessed for changes in cell morphology and rate of proliferation after treatment with NEAPP-exposed medium (PAM). To explore the functional mechanism, caspase 3/7, annexin V, and uptake of reactive oxygen species (ROS) were evaluated, along with the effect of the ROS scavenger N-acetylcysteine (NAC). Results PAM treatment for 24 h affected cell morphology, suggestive of induction of apoptosis. PAM cytotoxicity was influenced by the time of exposure to PAM, the type of cell line, and the number of cells seeded. Cells treated with PAM for 2 h demonstrated activated caspase 3/7 and an increased proportion of annexin V-positive cells compared with untreated cells. Additionally, ROS uptake was observed in PAM-treated cells, whereas NAC reduced the cytotoxicity induced by PAM presumably through reduction of ROS uptake. Furthermore, CD44 variant 9, which reportedly leads to glutathione synthesis and suppresses stress signaling of ROS, was overexpressed in PAM-resistant cells. Conclusions PAM treatment induced apoptosis of gastric cancer cells through generation and uptake of ROS. Local administration of PAM could develop into an option to treat peritoneal carcinomatosis.

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“…In particular, it has been shown that certain plasma species survive in water sufficiently long enough to constitute an alternative way of achieving disinfection through contact with the plasma-treated water (47). In a completely different departure from the potential that CAPs possess for the disinfection of contact lenses, it was recently demonstrated that the application of CAP to the surface of the eye is able to bring about the rapid disinfection of bacteria and fungi from the ocular surface without causing damage to the corneal epithelium and stroma (48).…”

Section: Discussionmentioning

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

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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.

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Disinfection of Ocular Cells and Tissues by Atmospheric-Pressure Cold Plasma

Cited by 109 publications

References 45 publications

Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus

Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus

Effectiveness of plasma treatment on gastric cancer cells

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

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