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- ItemOral SARS-CoV-2 reduction by local treatment: A plasma technology application?(Weinheim : Wiley-VCH, 2022) von Woedtke, Thomas; Gabriel, Gülsah; Schaible, Ulrich E.; Bekeschus, SanderThe SARS-CoV-2 pandemic reemphasized the importance of and need for efficient hygiene and disinfection measures. The coronavirus' efficient spread capitalizes on its airborne transmission routes via virus aerosol release from human oral and nasopharyngeal cavities. Besides the upper respiratory tract, efficient viral replication has been described in the epithelium of these two body cavities. To this end, the idea emerged to employ plasma technology to locally reduce mucosal viral loads as an additional measure to reduce patient infectivity. We here outline conceptual ideas of such treatment concepts within what is known in the antiviral actions of plasma treatment so far.
- ItemInactivation of airborne bacteria by plasma treatment and ionic wind for indoor air cleaning(Hoboken, NJ : Wiley Interscience, 2020) Prehn, Franziska; Timmermann, Eric; Kettlitz, Manfred; Schaufler, Katharina; Günther, Sebastian; Hahn, VeronikaAirborne bacteria are a general problem in medical or health care facilities with a high risk for nosocomial infections. Rooms with a continuous airflow, such as operation theaters, are of particular importance due to a possible dissemination and circulation of pathogens including multidrug-resistant microorganisms. In this regard, a cold atmospheric-pressure plasma (CAP) may be a possibility to support usual disinfection procedures due to its decontaminating properties. The aim of this study was to determine the antimicrobial efficacy of a plasma decontamination module that included a dielectric barrier discharge for plasma generation. Experimental parameters such as an airflow velocity of 4.5 m/s and microbial contaminations of approximately 6,000 colony-forming units (cfu)/m3 were used to simulate practical conditions of a ventilation system in an operating theater. The apathogenic microorganism Escherichia coli K12 DSM 11250/NCTC 10538 and the multidrug-resistant strains E. coli 21181 and 21182 (isolated from patients) were tested to determine the antimicrobial efficacy. In summary, the number of cfu was reduced by 31–89% for the tested E. coli strains, whereby E. coli K12 was the most susceptible strain toward inactivation by the designed plasma module. A possible correlation between the number or kind of resistances and susceptibility against plasma was discussed. The inactivation of microorganisms was affected by plasma intensity and size of the plasma treatment area. In addition, the differences of the antimicrobial efficacies caused through the nebulization of microorganisms in front (upstream) or behind (downstream) the plasma source were compared. The presence of ionic wind had no influence on the reduction of the number of cfu for E. coli K12, as the airflow velocity was too high for a successful precipitation, which would be a prerequisite for an increased antimicrobial efficacy. The inactivation of the tested microorganisms confirms the potential of CAP for the improvement of air quality. The scale-up of this model system may provide a novel tool for an effective air cleaning process.
- ItemCold Atmospheric Pressure Plasma Is Effective against P. gingivalis (HW24D-1) Mature Biofilms and Non-Genotoxic to Oral Cells(Basel : MDPI, 2022) de Morais Gouvêa Lima, Gabriela; Carta, Celina Faig Lima; Borges, Aline Chiodi; Nishime, Thalita Mayumi Castaldelli; da Silva, Cézar Augusto Villela; Caliari, Marcelo Vidigal; Mayer, Marcia Pinto Alves; Kostov, Konstantin Georgiev; Koga-Ito, Cristiane YumiThe effects of helium cold atmospheric pressure plasma (He-CAPP) jet on Porphyromonas gingivalis (HW24D-1) biofilm, on human gingival fibroblasts (HGF) and human gingival keratinocytes (OBA-9) were assessed. Standardized suspension of P. gingivalis was obtained, and biofilms were grown anaerobically for 48 h. After exposition to He-CAPP, the biofilm viability was evaluated by XTT assay. HGF were grown at 37 °C, in an CO2 chamber in DMEM, while OBA-9 cells were cultured in keratinocyte serum-free medium. After 24 h, plates were exposed to He-CAPP for 1 to 7 min. Plasma was generated using a commercial AC power supply with amplitude modulated signal (voltage amplitude of 20 kVp-p, frequency of 31.0 kHz and duty cycle of 22%). The corresponding discharge power was 0.6W at He flow rate of 1 L/min. DNA damage was accessed by static cytometry. Data were analyzed by GraphPad Prism (p < 0.05). Significant reductions in P. gingivalis viability in relation to non-treated groups were detected (p < 0.0001), directly proportional to exposure time. Treated groups were slightly aneuploid after 5- and 7-min treatment in HGF, and for 3 min in OBA-9 cells, with 1.2 DNA index mean. Helium cold atmospheric pressure plasma jet showed inhibitory effect on P. gingivalis mature biofilm and was not genotoxic for epithelial gingival cells and human oral fibroblasts.
- ItemPlasma-Treated Water Affects Listeria monocytogenes Vitality and Biofilm Structure(Lausanne : Frontiers Media, 2021) Handorf, Oliver; Pauker, Viktoria Isabella; Weihe, Thomas; Schäfer, Jan; Freund, Eric; Schnabel, Uta; Bekeschus, Sander; Riedel, Katharina; Ehlbeck, JörgBackground: Plasma-generated compounds (PGCs) such as plasma-processed air (PPA) or plasma-treated water (PTW) offer an increasingly important alternative for the control of microorganisms in hard-to-reach areas found in several industrial applications including the food industry. To this end, we studied the antimicrobial capacity of PTW on the vitality and biofilm formation of Listeria monocytogenes, a common foodborne pathogen. Results: Using a microwave plasma (MidiPLexc), 10 ml of deionized water was treated for 100, 300, and 900 s (pre-treatment time), after which the bacterial biofilm was exposed to the PTW for 1, 3, and 5 min (post-treatment time) for each pre-treatment time, separately. Colony-forming units (CFU) were significantly reduced by 4.7 log10 ± 0.29 log10, as well as the metabolic activity decreased by 47.9 ± 9.47% and the cell vitality by 69.5 ± 2.1%, compared to the control biofilms. LIVE/DEAD staining and fluorescence microscopy showed a positive correlation between treatment and incubation times, as well as reduction in vitality. Atomic force microscopy (AFM) indicated changes in the structure quality of the bacterial biofilm. Conclusion: These results indicate a promising antimicrobial impact of plasma-treated water on Listeria monocytogenes, which may lead to more targeted applications of plasma decontamination in the food industry in the future.
- ItemCold Atmospheric Plasma Jet as a Possible Adjuvant Therapy for Periodontal Disease(Basel : MDPI, 2021) Lima, Gabriela de Morais Gouvêa; Borges, Aline Chiodi; Nishime, Thalita Mayumi Castaldelli; Santana-Melo, Gabriela de Fatima; Kostov, Konstantin Georgiev; Mayer, Marcia Pinto Alves; Koga-Ito, Cristiane YumiDue 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.