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Non-thermal plasma activated water (PAW) has recently emerged as a powerful antimicrobial agent. Despite numerous potential bio-medical applications, studies concerning toxicity in live animals, especially after long-term exposure, are scarce. Our study aimed to assess the effects of long-term watering with PAW on the health of CD1 mice. PAW was prepared from distilled water with a GlidArc reactor according to a previously published protocol. The pH was 2.78. The mice received PAW (experimental group) or tap water (control group) daily for 90 days as the sole water source. After 90 days, the following investigations were performed on the euthanatized animals: gross necropsy, teeth mineral composition, histopathology, immunohistochemistry, hematology, blood biochemistry, methemoglobin level and cytokine profile. Mice tolerated PAW very well and no adverse effects were observed during the entire period of the experiment. Histopathological examination of the organs and tissues did not reveal any structural changes. Moreover, the expression of proliferation markers PCNA and Ki67 has not been identified in the epithelium of the upper digestive tract, indicating the absence of any pre- or neoplastic transformations. The results of our study demonstrated that long-term exposure to PAW caused no toxic effects and could be used as oral antiseptic solution in dental medicine.

The antibacterial and cell-proliferative character of atmospheric pressure plasma jets (APPJs) helps in the healing process of chronic wounds. However, control of the plasma-biological target interface remains an open issue. High vacuum ultraviolet/ultraviolet (VUV/UV) radiation and RONS flux from plasma may cause damage of a treated tissue; therefore, controlled interaction is essential. VUV/UV emission from argon APPJs and radiation control with aerosol injection in plasma effluent is the focus of this research. The aerosol effect on radiation is studied by a fluorescent target capable of resolving the plasma oxidation footprint. In addition, DNA damage is evaluated by plasmid DNA radiation assay and cell proliferation assay to assess safety aspects of the plasma jet, the effect of VUV/UV radiation, and its control with aerosol injection. Inevitable emission of VUV/UV radiation from plasmas during treatment is demonstrated in this work. Plasma has no antiproliferative effect on fibroblasts in short treatments ( t < 60 s), while long exposure has a cytotoxic effect, resulting in decreased cell survival. Radiation has no effect on cell survival in the medium due to absorption. However, a strong cytotoxic effect on the attached fibroblasts without the medium is apparent. VUV/UV radiation contributes 70% of the integral plasma effect in induction of single- and double-strand DNA breaks and cytotoxicity of the attached cells without the medium. Survival of the attached cells increases by 10% when aerosol is introduced between plasma and the cells. Injection of aerosol in the plasma effluent can help to control the plasma-cell/tissue interaction. Aerosol droplets in the effluent partially absorb UV emission from the plasma, limiting photon flux in the direction of the biological target. Herein, cold and safe plasma-aerosol treatment and a safe operational mode of treatment are demonstrated in a murine model.

As emerging chemical-free and eco-friendly technologies, nonthermal (gas discharge) plasma and (liquid phase) plasma-activated water (PAW) offer exceptional microbial disinfection solutions for biological, medical, environmental, and agricultural applications. Herein, we present electrohydraulic streamer discharge plasma (ESDP), which combines streamer discharge plasma (SDP) and PAW generated at a gas-liquid interface, to sterilize Chinese kale ( Brassica oleracea var. alboglabra) seeds contaminated with Alternaria brassicicola ( A. brassicicola ). The results showed that the ESDP treatment of A. brassicicola -inoculated seeds provides a ∼75% reduction of A. brassicicola (incident percentage) compared with nontreated seeds. Likewise, the healthy seedling percentage of the plasma-treated seeds was significantly improved to ∼70%, while that of the nontreated seeds remained at ∼15%. A microscopic examination was performed, and it confirmed that ESDP can damage the A. brassicicola spores attached to Chinese kale seeds and lead to severe morphological abnormalities after treatment. Also, an electric field simulation was performed, and it indicated that the strongly localized electric field at the liquid-gas interface on the seed surface boundary had initiated local breakdown of the gas at the air-liquid interface, resulting in exceptional physical-chemical reactions for antimicrobial efficacy beyond typical plasma treatments. Moreover, the optical emission spectra and physicochemical properties (pH, conductivity, and oxidation-reduction potential) showed that inactivation is mainly associated with the reactive oxygen-nitrogen species in the liquid and gas phases. We believe that this work is of great interest when using electrical discharge plasma on liquid interfaces in food, agricultural, and medical industries.

Due to the limitations of traditional periodontal therapies, and reported cold atmospheric plasma anti-inflammatory/antimicrobial activities, plasma could be an adjuvant therapy to periodontitis. Porphyromonas gingivalis was grown in blood agar. Standardized suspensions were plated on blood agar and plasma-treated for planktonic growth. For biofilm, dual-species Streptococcus gordonii + P. gingivalis biofilm grew for 48 h and then was plasma-treated. XTT assay and CFU counting were performed. Cytotoxicity was accessed immediately or after 24 h. Plasma was applied for 1, 3, 5 or 7 min. In vivo: Thirty C57BI/6 mice were subject to experimental periodontitis for 11 days. Immediately after ligature removal, animals were plasma-treated for 5 min once-Group P1 ( n = 10); twice (Day 11 and 13)-Group P2 ( n = 10); or not treated-Group S ( n = 10). Mice were euthanized on day 15. Histological and microtomography analyses were performed. Significance level was 5%. Halo diameter increased proportionally to time of exposure contrary to CFU/mL counting. Mean/SD of fibroblasts viability did not vary among the groups. Plasma was able to inhibit P. gingivalis in planktonic culture and biofilm in a cell-safe manner. Moreover, plasma treatment in vivo, for 5 min, tends to improve periodontal tissue recovery, proportionally to the number of plasma applications.

The increase in antibiotic resistance has become a global challenge to public health. In this study, an atmospheric cold plasma (ACP) system was applied for combating methicillin-resistant Staphylococcus aureus (MRSA) and its methicillin resistance gene (mecA) during food wastewater treatment. The plate count and flow cytometry methods were employed to estimate the damage in MRSA induced by plasma treatment. A quantitative real-time PCR (qPCR) method was used to assess the plasma-induced degradation of the mecA genes. The inactivation of MRSA and degradation of extracellular (e-) and intracellular (i-)mecA genes were investigated in phosphate buffered solution as a function of plasma exposure. A relatively low plasma influence of 0.12 kJ/cm 2 accounted for 5-log MRSA and 1.4-log e-mecA genes reduction, while only around 0.19-log degradation for i-mecA genes. As the plasma intensity was accumulated to 0.35 kJ/cm 2 , the reduction of e- and i-mecA genes was increased to 2.6 and 0.8 logs, respectively. The degradation of i-mecA genes was much slower than that of e-mecA genes due to the protective effects of the outer envelopes or intracellular components against plasma. The matrix effect of wastewater effluents shielded both antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) from plasma disinfection, which led to a lower degradation efficacy. Our results could support the development and optimization of plasma-based wastewater treatment., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Interactions of living cells with cold plasma of electrical discharges affect cell physiology, often resulting in the loss of viability. However, the mechanisms involved in cell killing are poorly understood, and dissection of cellular pathways or structures affected by plasma using simple eukaryotic models is needed. Using selected genetic mutants of yeast (Saccharomyces cerevisiae), we investigated the role of oxidative stress and yeast apoptosis in plasma-induced cell killing. Increased sensitivity of yeast strains deficient in superoxide dismutases indicated that reactive oxygen species generated in the plasma are among the most prominent factors involved in killing of yeast cells. In mutant strains with a deletion of the key components of yeast apoptotic pathway, the sensitivity of cells towards the plasma treatment remained unaffected. Yeast apoptosis, thus, does not appear to play a significant role in plasma-induced cell killing of yeast.

Promising cold physical plasma sources have been developed in the field of plasma medicine. An important prerequisite to their clinical use is lack of genotoxic effects in cells. During optimization of one or even different plasma sources for a specific application, large numbers of samples need to be analyzed. There are soft and easy-to-assess markers for genotoxic stress such as phosphorylation of histone H2AX (γH2AX) but only few tests are accredited by the OECD with regard to mutagenicity detection. The micronucleus (MN) assay is among them but often requires manual counting of many thousands of cells per sample under the microscope. A high-throughput MN assay is presented using image flow cytometry and image analysis software. A human lymphocyte cell line was treated with plasma generated with ten different feed gas conditions corresponding to distinct reactive species patterns that were investigated for their genotoxic potential. Several millions of cells were automatically analyzed by a MN quantification strategy outlined in detail in this work. Our data demonstrates the absence of newly formed MN in any feed gas condition using the atmospheric pressure plasma jet kINPen. As positive control, ionizing radiation gave a significant 5-fold increase in micronucleus frequency. Thus, this assay is suitable to assess the genotoxic potential in large sample sets of cells exposed chemical or physical agents including plasmas in an efficient, reliable, and semiautomated manner. Environ. Mol. Mutagen. 59:268-277, 2018. © 2018 Wiley Periodicals, Inc., (© 2018 Wiley Periodicals, Inc.)

Oxidative stress enhances cellular DNA oxidation and may cause mutations in DNA bases, including 8‑oxoguanine (8‑oxoG). Our recent study reported that exposure of cells to non‑thermal dielectric barrier discharge (DBD) plasma generates reactive oxygen species and damages DNA. The present study investigated the effect of non‑thermal DBD plasma exposure on the formation of 8‑oxoG in HaCaT human keratinocytes. Cells exposed to DBD plasma exhibited increased level of 8‑oxoG. In addition, mRNA and protein expression levels of 8‑oxoguanine glycosylase 1 (OGG1), an 8‑oxoG repair enzyme, were reduced in plasma‑exposed cells. Furthermore, the expression level of nuclear factor erythroid 2‑related factor 2 (Nrf2), a transcription factor that regulates OGG1 gene expression, was reduced following exposure to DBD plasma. Pretreatment of cells with an antioxidant, N‑acetyl cysteine (NAC), prior to plasma exposure suppressed the formation of 8‑oxoG and restored the expression levels of OGG1 and Nrf2. In addition, phosphorylation of protein kinase B (Akt), which regulates the activation of Nrf2, was reduced following plasma exposure. However, phosphorylation was restored by pretreatment with NAC. These findings suggested that non‑thermal DBD plasma exposure generates 8‑oxoG via inhibition of the Akt‑Nrf2‑OGG1 signaling pathway in HaCaT cells.

Non-thermal atmospheric pressure plasma (NTP) has been shown to induce cell death in various mammalian cancer cells. Accumulated evidence also shows that NTP could be clinically used in cancer therapy. However, the current NTP-based applications lack target specificity. Here, a novel method in NTP-mediated cancer therapeutics was described with enhanced target specificity by treating EGF (epidermal growth factor)-conjugated GNP (gold nanoparticle). The treatment with EGF-conjugated GNP complex, followed by NTP irradiation showed selective apoptosis of cells having receptor-mediated endocytosis. NTP triggered γ-H2AX elevation which is a typical response elicited by DNA damage. These results suggest that EGF-conjugated GNP functions as an important adjuvant which gives target specificity in applications of conventional plasma therapy.

In this paper, three mutants from wild Saccharomyces cerevisiae HBU2.558, called U2.558, UN2.558, and UNA2.558, were screened by UV, sodium nitrite, Atmospheric and room temperature plasma, respectively. Glutathione production of the three mutants increased by 41.86, 72.09 and 56.76%, respectively. We detected the activity of glutathione synthetases and found that its activity was improved. Amino acid sequences of three mutant colonies were compared with HBU2.558. Four mutants: Leu51→Pro51 (L51P), Glu62→Val62 (E62V), Ala332→Glu332 (A332E) and Ser653→Gly653 (S653G) were found in the analysis of γ-glutamylcysteine ligase. L51 is located adjacently to the two active sites of GCL/E/Mg 2+ /ADP complex in the overall GCL structure. L51P mutant spread distortion on the β-sheet due to the fact that the φ was changed from -50.4° to -40.2°. A mutant Leu54→Pro54 (L54P) was found in the analysis of glutathione synthetase, and L54 was an amino acid located between an α-helix and a β-sheet. The results confirm that introduction of proline located at the middle of the β-sheet or at the N- or C-terminal between α-helix and β-sheet or, i.e., L51P and L54P, changed the φ, rigidity, hydrophobicity and conformational entropy, thus increased protein stability and improved the enzyme activity.

The exact mechanisms by which nanoparticles, especially those composed of soft materials, are modified by gas plasma remain unclear. Here, we used respiratory syncytial virus (RSV), which has a diameter of 80-350nm, as a model system to identify important factors for gas plasma modification of nanoparticles composed of soft materials. Nitrogen gas plasma, generated by applying a short high-voltage pulse using a static induction (SI) thyristor power supply produced reactive chemical species (RCS) and caused virus inactivation. The plasma treatment altered the viral genomic RNA, while treatment with a relatively low concentration of hydrogen peroxide, which is a neutral chemical species among RCS, effectively inactivated the virus. Furthermore, a zero dimensional kinetic global model of the reaction scheme during gas plasma generation identified the production of various RCS, including neutral chemical species. Our findings suggest the nitrogen gas plasma generates RCS, including neutral species that damage the viral genomic RNA, leading to virus inactivation. Thus, RCS generated by gas plasma appears to be crucial for virus inactivation, suggesting this may constitute an important factor in terms of the efficient modification of nanoparticles composed of soft materials., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Cold atmospheric argon plasma is recognized as a new contact free approach for the decrease of bacterial load on chronic wounds in patients. So far very limited data are available on its toxicity and mutagenicity on eukaryotic cells. Thus, the toxic/mutagenic potential of cold atmospheric argon plasma using the MicroPlaSter β ® , which has been used efficiently in humans treating chronic and acute wounds, was investigated using the XTT assay in keratinocytes and fibroblasts and the HGPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 Chinese hamster cells. The tested clinical parameter of a 2 min cold atmospheric argon plasma treatment revealed no relevant toxicity on keratinocytes (viability: 76% ± 0.17%) and on fibroblasts (viability: 81.8 ± 0.10) after 72 hr as compared to the untreated controls. No mutagenicity was detected in the HGPRT assay with V79 cells even after repetitive CAP treatments of 2-10 min every 24 hr for up to 5 days. In contrast, UV-C irradiation of V79 cells, used as a positive control in the HGPRT test, led to DNA damage and mutagenic effects. Our findings indicate that cold atmospheric plasma using the MicroPlaSter β ® shows negligible effects on keratinocytes and fibroblasts but no mutagenic potential in the HGPRT assay, indicating a new contact free safe technology. Environ. Mol. Mutagen. 58:172-177, 2017. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

The generation of reactive oxygen and nitrogen species (RONS) has been found to occur during inflammatory procedures, during cell ischemia, and in various crucial developmental processes such as cell differentiation and along cell signaling pathways. The most common sources of intracellular RONS are the mitochondrial electron transport system, NADH oxidase, and cytochrome P450. In this review, we analyzed the extracellular and intracellular sources of reactive species, their cell signaling pathways, the mechanisms of action, and their positive and negative effects in the dental field. In dentistry, ROS can be found-in lasers, photosensitizers, bleaching agents, cold plasma, and even resin cements, all of which contribute to the generation and prevalence of ROS. Nonthermal plasma has been used as a source of ROS for biomedical applications and has the potential for use with dental stem cells as well. There are different types of dental stem cells, but their therapeutic use remains largely untapped, with the focus currently on only periodontal ligament stem cells. More research is necessary in this area, including studies about ROS mechanisms with dental cells, along with the utilization of reactive species in redox medicine. Such studies will help to provide successful treatment modalities for various diseases.

No prior research has investigated whether the cold plasma treatment (CPT) resulted in the formation of toxic compounds. Therefore, this study carried out the experiment to check the safety of edible films treated with cold plasma by examining their acute and subacute oral toxicity in a rat model. Single-dose acute (5000 mg/kg body weight) and 14-d subacute (1000 mg/kg body weight/day) oral toxicity of cold plasma-treated edible films was assessed for male and female Sprague-Dawley (SD) rats. Rats administered 5000 mg/kg of edible film did not show the signs of acute toxicity or death after 14 d of observation. Similarly, no signs of acute toxicity or death were recorded during 14 d in rats administered 1000 mg/kg/day of edible film treated with cold plasma. Although changes in the levels of several blood components (hematocrit, hemoglobin, bilirubin, creatinine, and aspartate aminotransferase) of samples were observed, the changes compared to the control were considered to be toxicologically irrelevant as their levels were within normal physiological ranges. Macroscopic analysis showed there were no changes in color or texture of representative liver sections of SD rats following the oral administration of edible films with CPT (F-CP) or without CPT (F-NT). The results demonstrate that the cold plasma-treated edible film possessed very low toxicity, suggesting that CPT does not generate harmful by-products in the edible film., (© 2016 Institute of Food Technologists®.)

The therapeutic potential of nonthermal plasma for cancer treatment has been reported recently. The heterogeneity of cancer cells need to be addressed to design effective anticancer treatments. Here, we show that treatment with nonthermal atmospheric-pressure plasma dissolved in a liquid (liquid plasma) induces oxidative stress in heterogeneous populations of cancer cells and ultimately kills these cells via apoptosis, regardless of genetic status, e.g., mutations in p53 and other DNA-damage-response genes. We found that liquid plasma markedly increased the concentration of intracellular and mitochondrial reactive oxygen species (ROS), reflecting an influx from the extracellular milieu. Liquid plasma contributed to mitochondrial accumulation of ROS and depolarization of mitochondrial membrane potential with consequent cell death. Healthy normal cells, however, were hardly affected by the liquid-plasma treatment. The antioxidant N-acetylcysteine blocked liquid-plasma-induced cell death. A knockdown of CuZn-superoxide dismutase or Mn-SOD enhanced the plasma-induced cell death, whereas expression of exogenous CuZn-SOD, Mn-SOD, or catalase blocked the cell death. These results suggest that the mitochondrial dysfunction mediated by ROS production is a key contributor to liquid-plasma-induced apoptotic cell death, regardless of genetic variation. Thus, liquid plasma may have clinical applications, e.g., the development of therapeutic strategies and prevention of disease progression despite tumor heterogeneity.

Cold atmospheric pressure plasmas represent a favorable option for the treatment of heat sensitive materials and human or animal tissue. Beneficial effects have been documented in a variety of medical conditions, e.g., in the treatment of chronic wounds. It is assumed that the main mechanism of the plasma's efficacy is mediated by a stimulating dissipation of energy via radiation and/or chemical energy. Although no evidence on undesired side effects of a plasma treatment has yet been presented, skepticism toward the safety of the exposure to plasma is present. However, only little data regarding the mutagenic potential of this new treatment option is available. Accordingly, we investigated the mutagenic potential of an argon plasma jet (kinpen) using different testing systems in accordance with ISO norms and multiple cell lines: a HPRT1 mutation assay, a micronucleus formation assay, and a colony formation assay. Moderate plasma treatment up to 180 s did not increase genotoxicity in any assay or cell type investigated. We conclude that treatment with the argon plasma jet kinpen did not display a mutagenic potential under the test conditions applied and may from this perspective be regarded as safe for the use in biomedical applications., (Copyright © 2016. Published by Elsevier B.V.)

Non-thermal plasma (NTP) was tested as an in vitro deactivation method on four human pathogenic dermatophytes belonging to all ecological groups including anthropophilic Trichophyton rubrum and Trichophyton interdigitale, zoophilic Arthroderma benhamiae, and geophilic Microsporum gypseum. The identification of all strains was confirmed by sequencing of ITS rDNA region (internal transcribed spacer region of ribosomal DNA). Dermatophyte spores were suspended in water or inoculated on agar plates and exposed to NTP generated by a positive or negative corona discharge, or cometary discharge. After 15 min of exposure to NTP a significant decrease in the number of surviving spores in water suspensions was observed in all species. Complete spore inactivation and thus decontamination was observed in anthropophilic species after 25 min of exposure. Similarly, a significant decrease in the number of surviving spores was observed after 10-15 min of exposure to NTP on the surface of agar plates with full inhibition after 25 min in all tested species except of M. gypseum. Although the sensitivity of dermatophytes to the action of NTP appears to be lower than that of bacteria and yeast, our results suggest that NTP has the potential to be used as an alternative treatment strategy for dermatophytosis and could be useful for surface decontamination in clinical practice., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Atmospheric 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., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Atmospheric-pressure N2, He, air, and O2 microplasma arrays have been used to inactivate Escherichia coli cells suspended in aqueous solution. Measurements show that the efficiency of inactivation of E. coli cells is strongly dependent on the feed gases used, the plasma treatment time, and the discharge power. Compared to atmospheric-pressure N2 and He microplasma arrays, air and O2 microplasma arrays may be utilized to more efficiently kill E. coli cells in aqueous solution. The efficiencies of inactivation of E. coli cells in water can be well described by using the chemical reaction rate model, where reactive oxygen species play a crucial role in the inactivation process. Analysis indicates that plasma-generated reactive species can react with E. coli cells in water by direct or indirect interactions., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Atmospheric Pressure Plasma (APP) is being used widely in a variety of biomedical applications. Extensive research in the field of plasma medicine has shown the induction of DNA damage by APP in a dose-dependent manner in both prokaryotic and eukaryotic systems. Recent evidence suggests that APP-induced DNA damage shows potential benefits in many applications, such as sterilization and cancer therapy. However, in several other applications, such as wound healing and dentistry, DNA damage can be detrimental. This review reports on the extensive investigations devoted to APP interactions with DNA, with an emphasis on the critical role of reactive species in plasma-induced damage to DNA. The review consists of three main sections dedicated to fundamental knowledge of the interactions of reactive oxygen species (ROS)/reactive nitrogen species (RNS) with DNA and its components, as well as the effects of APP on isolated and cellular DNA in prokaryotes and eukaryotes.

In the past few years, cold atmospheric plasma (CAP) has evolved into a new tool in the fight against nosocomial infections and antibiotic-resistant microorganisms. The products generated by the plasma-electrons, ions, reactive species and UV light-represent a 'lethal cocktail' for different kinds of pathogen, which opens up possible applications in hygiene and medicine. Nevertheless, to ensure the safe usage of CAP on skin (e.g., to treat wounds or skin diseases) several pre-clinical in vitro studies have to be performed before implementing clinical trials on humans. In the study presented here, inactivation experiments with Escherichia coli were carried out to identify the necessary plasma dosage for a 5 log reduction: with a small hand-held battery-operated CAP device, these disinfection properties were achieved after application during 30s. This and higher plasma dosages were then used to analyze the mutagenicity induced in V79 Chinese hamster cells-to furthermore define a 'safe application window'-with the HPRT (hypoxanthine-guanine phosphoribosyl transferase) mutation assay. The results show that a CAP treatment of up to 240 s and repeated treatments of 30s every 12h did not induce mutagenicity at the Hprt locus beyond naturally occurring spontaneous mutations., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Plasma medicine is a novel, highly interdisciplinary field of research. Although the knowledge is rare concerning plasma based biomedical mechanisms, correct dosages and treatment times, animal experiments have been carried out. To follow the 3Rs (reduction, refinement, replacement), it is necessary to define methods for the screening of plasma parameters. In order to determine a reliable test and validate the use of tissue tolerable plasma (TTP) for the treatment of chronic wounds, we have selected the modified hen's egg test on the chorioallantoic membrane (mod. HET-CAM) as a model to benchmark the inflammation potential of plasma. Inflammations of different intensities provoked by using an HF-plasma jet corresponded to the time of plasma-tissue interaction. Additionally, the plasma mode and the gas composition were changed to assess their influence on the efficacy of treatment. Pulsed plasma led to the mildest inflammation, while the addition of 0.1% oxygen to the argon carrier gas led to the most distinct reaction. It was found that the influence of the exposure time was greater than that of the mode and the gas composition. All inflammations were alleviated, when hydrocortisone (HC) was added immediately after plasma treatment. The results of the study demonstrate that the modified HET-CAM test is suitable for screening plasma sources and for the determination of the optimum parameters for treatment of chronic wounds. To transfer the chronic wound into an acute healing wound without harmful inflammation, the maximum time for plasma-tissue interaction should not exceed 5s with the tested plasma source. Furthermore, it is possible to induce defined plasma-inflammations on the chorioallantoic membrane and to determine the anti-inflammatory potential of test substances., (Copyright © 2010 Elsevier Ltd. All rights reserved.)