Cold Atmospheric Pressure Plasma Jet Reduces Trichophyton rubrum Adherence and Infection Capacity

Cold Atmospheric Plasma Jet as a Possible Adjuvant Therapy for Periodontal Disease

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.

Cold atmospheric pressure plasma (CAPP) as a new alternative treatment method for onychomycosis caused by Trichophyton verrucosum: in vitro studies

PURPOSE

Anthropophilic dermatophytes as etiological factors of onychomycoses are more common than zoophilic fungi. In the case of the latter, reverse zoonoses are possible, which poses a threat to the persistence of dermatophytes in the environment. Nevertheless, without treatment, both types of tinea unguium may lead to complete nail plate destruction and secondary mixed infections with fungi and bacteria. One of the zoophilic dermatophytes that cause onychomycosis is Trichophyton verrucosum, whose prevalence has been increasing in recent years. Such infections are usually treated with allylamines and/or azoles, but such a conventional treatment of infections caused by T. verrucosum often fails or is discontinued by patients.

METHODS

Herein, we reveal the results of our in vitro studies related to direct application of cold atmospheric pressure plasma (CAPP) on Trichophyton verrucosum growth, germination and adherence to nail as a new alternative treatment method of such types of dermatomycoses.

RESULTS

Our in vitro studies showed that, while exposure to CAPP for 10 min delays germination of conidia and clearly impairs the fitness of the fungal structures, 15 min is enough to kill all fungal elements exposed to plasma. Moreover, the SEM images revealed that T. verrucosum cultures exposed to CAPP for 10 and 15 min were not able to invade the nail fragments.

CONCLUSION

The results revealed that single exposure to CAPP was able to inhibit T. verrucosum growth and infection capacity. Hence, cold atmospheric pressure plasma should be considered as a promising alternative treatment of onychomycoses.

Inactivation of Dermatophytes Causing Onychomycosis Using Non-Thermal Plasma as a Prerequisite for Therapy

Following our previous study of the therapy of onychomycosis by non-thermal plasma (NTP) and nail hygiene and to obtain some prerequisite data of dermatophytes sensitivity, the dynamics of those inactivation by NTP plasma was monitored for various strains of Trichophyton iterdigitale, Trichophyton benhamiae, Trichophyton rubrum, and Microsporum canis. Three strains of each species on agar plates were exposed with plasma produced by a DC corona discharge in the point-to-ring arrangement in various time intervals. Although all strains were sufficiently sensitive to plasma action, significant differences were observed in their sensitivity and inactivation dynamics. These differences did not correlate with the species classification of individual strains, but could be assigned to four arbitrarily created types of strain response to NTP according to their sensitivity. These results indicate that the sensitivity to plasma is not an inherent property of the fungal species, but varies from strain to strain.

Inhibitory Effect of Cold Atmospheric Plasma on Chronic Wound-Related Multispecies Biofilms

The presence of microbial biofilms in the wounds affects negatively the healing process and can contribute to therapeutic failures. This study aimed to establish the effective parameters of cold atmospheric plasma (CAP) against wound-related multispecies and monospecies biofilms, and to evaluate the cytotoxicity and genotoxicity of the protocol. Monospecies and multispecies biofilms were formed by methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Enterococcus faecalis. The monospecies biofilms were grown in 96 wells plates and multispecies biofilm were formed on collagen membranes. The biofilms were exposed to helium CAP for 1, 3, 5 and 7 min. In monospecies biofilms, the inhibitory effect was detected after 1 min of exposure for E. faecalis and after 3 min for MRSA. A reduction in P. aeruginosa biofilm’s viability was detected after 7 min of exposure. For the multispecies biofilms, the reduction in the overall viability was detected after 5 min of exposure to CAP. Additionally, cytotoxicity and genotoxicity were evaluated by MTT assay and static cytometry, respectively. CAP showed low cytotoxicity and no genotoxicity to mouse fibroblastic cell line (3T3). It could be concluded that He-CAP showed inhibitory effect on wound-related multispecies biofilms, with low cytotoxicity and genotoxicity to mammalian cells. These findings point out the potential application of CAP in wound care.

Applications of Cold Atmospheric Pressure Plasma in Dentistry

Plasma is an electrically conducting medium that responds to electric and magnetic fields. It consists of large quantities of highly reactive species, such as ions, energetic electrons, exited atoms and molecules, ultraviolet photons, and metastable and active radicals. Non-thermal or cold plasmas are partially ionized gases whose electron temperatures usually exceed several tens of thousand degrees K, while the ions and neutrals have much lower temperatures. Due to the presence of reactive species at low temperature, the biological effects of non-thermal plasmas have been studied for application in the medical area with promising results. This review outlines the application of cold atmospheric pressure plasma (CAPP) in dentistry for the control of several pathogenic microorganisms, induction of anti-inflammatory, tissue repair effects and apoptosis of cancer cells, with low toxicity to healthy cells. Therefore, CAPP has potential to be applied in many areas of dentistry such as cariology, periodontology, endodontics and oral oncology.

Cold atmospheric pressure (physical) plasma in dermatology: where are we today?

Cold atmospheric pressure plasma is physical plasma (essentially ionized gas) created at room temperature and atmospheric pressure, and it has complex effects on cells, tissues, and living organisms. These effects are studied extensively for medical and dermatological use. This article reviews current achievements and new trends in clinical dermatological cold plasma research, discusses the basics of plasma physics and plasma engineering, and describes the most important areas of laboratory plasma research to provide a well-rounded understanding of the nature, present applications, and future promise of this exciting, emerging technology.

Cold sub-atmospheric and atmospheric pressure plasma for the treatment of Trichophyton rubrum onychomycosis: An in-vitro study

Previous studies have suggested the applicability of cold atmospheric pressure plasma for the treatment of onychomycosis. Whether delivering cold plasma in sub-atmospheric pressure would be beneficial for this purpose is yet to be established. The current study aimed to evaluate efficacy of cold sub-atmospheric and atmospheric pressure plasma in Trichophyton rubrum growth inhibition. Bovine nails infected with T. rubrum were treated by a cold air plasma device, which enables utilizing plasma in sub-atmospheric pressures (Low = 100 millibar; High = 300 millibar) or atmospheric pressure. The infected foci were exposed to the plasma source directly or indirectly. Treatment with high sub-atmospheric pressure setting achieved T. rubrum growth reduction of 94.0% and 73.0%, for direct and indirect exposure to the plasma source, respectively (P < .001). Low sub-atmospheric pressure setting achieved similar T. rubrum growth reduction of 86.2% for direct exposure to the plasma source (P < .001), but only marginally significant 58.8% reduction rate for indirect exposure to the plasma source (P = .056). None statistically significant fungal growth reduction was attained with the use of atmospheric pressure setting. Cold plasma was shown to effectively inhibit T. rubrum nail growth, with sub-atmospheric pressure setting achieving better outcome than atmospheric pressure.

Kostov K. Study of Modified Area of Polymer Samples Exposed to a He Atmospheric Pressure Plasma Jet Using Different Treatment Conditions

In the last decade atmospheric pressure plasma jets (APPJs) have been routinely employed for surface processing of polymers due to their capability of generating very reactive chemistry at near-ambient temperature conditions. Usually, the plasma jet modification effect spans over a limited area (typically a few cm²), therefore, for industrial applications, where treatment of large and irregular surfaces is needed, jet and/or sample manipulations are required. More specifically, for treating hollow objects, like pipes and containers, the plasma jet must be introduced inside of them. In this case, a normal jet incidence to treated surface is difficult if not impossible to maintain. In this paper, a plasma jet produced at the end of a long flexible plastic tube was used to treat polyethylene terephthalate (PET) samples with different incidence angles and using different process parameters. Decreasing the angle formed between the plasma plume and the substrate leads to increase in the modified area as detected by surface wettability analysis. The same trend was confirmed by the distribution of reactive oxygen species (ROS), expanding on starch-iodine-agar plates, where a greater area was covered when the APPJ was tilted. Additionally, UV-VUV irradiation profiles obtained from the plasma jet spreading on the surface confirms such behavior.