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Cold Physical Plasmas in the Field of Hygiene-Relevance, Significance, and Future Applications
Abstract
Cold physical plasmas ignited a technological spark in industry, biotechnology, and medicine. Especially the field of hygiene benefited of the plasma's exceptional activity against pathogenic microorganisms. Together with plasma-based surface functionalization, these qualities are highly relevant in a variety of processes in health care, such as the decontamination or sterilization of medical devices, food, packaging materials, waste water, or indoor air. In medicine, plasma has proven to show promising antiseptic results on skin and mucosal membranes in infection-related diseases in dermatology and dentistry. This comprehensive review will discuss the current applications of cold plasma in the fields of hygiene, and will provide a promising outlook on many applications yet to come.
Supplementary resource (1)
... One of these recent technologies is cold plasma that was primarily utilized for improving the printing and adhesion properties of polymers, increasing surface energy of materials and several applications in field of electronics [7]. Moreover, cold plasma can be applied in various industries such as textile, medicine, biotechnology, electronic, as well as water and air purification [8]. In the case of food industry, cold plasma technology can be utilized in microbial decontamination of food products, degradation of toxins and pesticides residue in foods, enzyme inactivation, food packaging and modification of food components as well as sterilization [8][9][10][11][12]. ...
... Moreover, cold plasma can be applied in various industries such as textile, medicine, biotechnology, electronic, as well as water and air purification [8]. In the case of food industry, cold plasma technology can be utilized in microbial decontamination of food products, degradation of toxins and pesticides residue in foods, enzyme inactivation, food packaging and modification of food components as well as sterilization [8][9][10][11][12]. Cold plasma can also be categorized to atmospheric and low-pressure plasma depending on the pressure conditions. ...
Atmospheric cold plasma (ACP) is an emerging technology which has increased attraction due to the consumers’ tendency toward fresh and minimally processed food products. This non-thermal technology has been considered as a promising tool for decontamination of foods, modification of food components as well as food packaging. The potential interactions of cold plasma species with food components and consequently its effect on food quality is of high importance. Proteins are the main food constituent in food formulations regarding both nutritional and technological points of view. The susceptibility of native proteins to reactive species created through ACP treatment should be considered regarding the power supply, type of feeding gas and its pressure, exposure time, input voltage and current flow. However, the protein characteristics and the manner in which they are exposed are also important to be considered. This review article is aimed to investigate the technological and nutritional characteristics of proteins during atmospheric cold plasma treatment.
... [16][17][18][19] In addition to traditional uses for the surface reforming on materials, such as culture dishes and contact lenses, other applications of LTP has enlarged including the induction of apoptosis 20) and blood coagulation. 21) Concerning the radicals from LTP, earlier studies had demonstrated that LTP treatment reduced infective inflammation by the bactericidal effect, regardless of antibiotic resistance [22][23][24][25] while other papers have shown that it stimulates cell proliferation via chemical modifications to cell surface molecules by ROS and reactive nitrogen species (e.g. NO, NO 2 and N 2 O). ...
... Though either current and electric charge on direct use of plasma treatment may produce the differential inhibitory effect for parasite growth, the exact mechanisms remain unclear. Referring to the earlier studies showing a possibility that the LTP-treated culture media could deliver the effective oxidative stress than direct treatment by LTP, [22][23][24][25]39) further studies needs to determine the kinds of active species forming the oxidative stresses in the LTP-treated culture media and phagosomes. ...
Trypanosoma brucei ( Tb ) is a pathogenic protozoan causing sleeping sickness in humans. Despite little knowledge of how the produced reactive oxygen species (ROS) kills this protozoan, the research on the killing mechanism using chemical compounds and the phagosome in the macrophages has suggested that the protozoan is highly susceptible to the increased oxidative stress. Because the prescribed drug can react with various kinds of molecules and the second produced intermediate compounds, in this study, we clarified the immediate killing effect on Tb in the condition of increased oxidative stress using a low-temperature plasma at atmospheric pressure (LTP) equipment. Results Show the significant growth inhibition of Tb in the LTP-treated medium, the loss of morphological homeostasis with twisted to puffed appearance, and demonstrated the swelled changes on mitochondria and endoplasmic reticulum. In conclusion, this study revealed how the increased oxidative stress kills Tb using LTP technology.
... In summary, medical gas plasma systems are operated at atmospheric pressure and body temperature, expelling ROS/RNS cocktails locally to the exposed site, and treatment effects in tissues and wounds have been demonstrated, as outlined in the subsequent preclinical and clinical studies. For a comprehensive overview of gas plasma devices and operation principles, antimicrobial effects, and in vitro findings in eukaryotic cells, the reader is referred to reviews on these topics [62][63][64][65][66][67][68][69]. ...
Defective wound healing poses a significant burden on patients and healthcare systems. In recent years, a novel reactive oxygen and nitrogen species (ROS/RNS) based therapy has received considerable attention among dermatologists for targeting chronic wounds. The multifaceted ROS/RNS are generated using gas plasma technology, a partially ionized gas operated at body temperature. This review integrates preclinical and clinical evidence into a set of working hypotheses mainly based on redox processes aiding in elucidating the mechanisms of action and optimizing gas plasmas for therapeutic purposes. These hypotheses include increased wound tissue oxygenation and vascularization, amplified apoptosis of senescent cells, redox signaling, and augmented microbial inactivation. Instead of a dominant role of a single effector, it is proposed that all mechanisms act in concert in gas plasma-stimulated healing, rationalizing the use of this technology in therapy-resistant wounds. Finally, addressable current challenges and future concepts are outlined, which may further promote the clinical utilization, efficacy, and safety of gas plasma technology in wound care in the future.
... Against this background, CAP treatment can be considered a new alternative in anti-oncological therapy. It has been shown that CAP treatment can inhibit both the proliferation and the cell mobility of in vitro propagated tumor cells [35,[47][48][49]. ...
Background:
Cold atmospheric plasma (CAP) is increasingly used in the field of oncology. Many of the mechanisms of action of CAP, such as inhibiting proliferation, DNA breakage, or the destruction of cell membrane integrity, have been investigated in many different types of tumors. In this regard, data are available from both in vivo and in vitro studies. Not only the direct treatment of a tumor but also the influence on its blood supply play a decisive role in the success of the therapy and the patient's further prognosis. Whether the CAP influences this process is unknown, and the first indications in this regard are addressed in this study.
Methods:
Two different devices, kINPen and MiniJet, were used as CAP sources. Human endothelial cell line HDMEC were treated directly and indirectly with CAP, and growth kinetics were performed. To indicate apoptotic processes, caspase-3/7 assay and TUNEL assay were used. The influence of CAP on cellular metabolism was examined using the MTT and glucose assay. After CAP exposure, tube formation assay was performed to examine the capillary tube formation abilities of HDMEC and their migration was messured in separate assays. To investigate in a possible mutagenic effect of CAP treatment, a hypoxanthine-guanine-phosphoribosyl-transferase assay with non malignant cell (CCL-93) line was performed.
Results:
The direct CAP treatment of the HDMEC showed a robust growth-inhibiting effect, but the indirect one did not. The MMT assay showed an apparent reduction in cell metabolism in the first 24 h after CAP treatment, which appeared to normalize 48 h and 72 h after CAP application. These results were also confirmed by the glucose assay. The caspase 3/7 assay and TUNEL assay showed a significant increase in apoptotic processes in the HDMEC after CAP treatment. These results were independent of the CAP device. Both the migration and tube formation of HDMEC were significant inhibited after CAP-treatment. No malignant effects could be demonstrated by the CAP treatment on a non-malignant cell line.
... It has been shown that after treatment of tumor cells with CAP, produced antiproliferative effects in varying tumor entities including carcinomas of the lung, ovaries, pancreas, and prostate, as well as osteosarcoma (5)(6)(7)(8)(9). In addition, CAP possesses antimicrobial, antiseptic, immunomodulating, antiinflammatory and wound healing promoting properties (10,11), which is why CAP has also been used in the treatment of body surfaces (skin diseases including skin tumours, tumours of the oral cavity) (12). Due to the short half-life of the reactive particles, CAP effects are temporally and locally limited. ...
Background/aim:
Mammary carcinoma (MC) remains one of the leading causes of morbidity and mortality in the female population worldwide. Cold physical plasma at atmospheric pressure (CAP) has an antioncogenic effect on tumor cells, and its anticancer properties may complement or even extend existing treatment options. In the present study, the efficacy of CAP was characterized on an MC in vitro cell culture system.
Materials and methods:
MC cells (MCF-7, MDA-MB-231) were directly treated with CAP or incubated with CAP-treated cell culture medium. Cell growth, cell mobility and apoptosis were subsequently analyzed.
Results:
A single treatment of MC cells with CAP and CAP treated medium led to a treatment-time dependent reduction of cell growth. Furthermore, CAP exposure led to a loss of cellular motility and induced apoptosis.
Conclusion:
Due to its anticancer properties, CAP treatment is an innovative and promising physical approach to expand and complement the treatment options for MC. In particular, a combination of CAP application with surgical and/or chemotherapeutic interventions might significantly improve the therapeutic outcomes.
... Since the early 1990s, research has increasingly been undertaken at the interface between physics and the life sciences in order to characterize the biological effects of cold plasma and to identify new areas of application for medical use (14,15). Until now, cold plasma has been used in hygiene to sterilize surgical instruments, implants and other mainly thermally sensitive materials (16)(17)(18). Furthermore, cold plasma is also approved for the treatment of dermatological diseases and is used with great success, particularly in the treatment of chronic wounds (19,20). ...
The principles of physics and precision engineering have allowed many technologies to enter standard treatment regimens for a range of diseases. Recently, a new type of technology has been accredited as safe and efficient routine procedure in dermatology in Europe: cold physical plasma. Several accredited devices successfully restrain the powerful energy of plasmas to make them available for therapeutic purposes. Herein, we introduce an introduction to the concept of cold physical plasmas and highlight some fields of their medical applications.
... Thus, both direct (superficial treatment) and indirect (treated rinsing solutions) treatments with CAP could represent a further therapeutic option as well as optimization of the BK virus treatment. 22,23 In summary, due to poor data availability, there is still no coherent standard therapy. Therefore, further retro-and prospective studies to optimize the therapy, to improve patient outcome, and to reduce morbidity seem to be essential. ...
Currently, there is no standard therapy for a BK virus infection of the urogenital tract
in immunocompromised, stem cell transplanted patients, so that early diagnosis and
introduction of supportive measures have the highest response rates to date.
The 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. Plasma could be a promising tool to locally reduce mucosal viral loads in the upper respiratory tract as an additional measure to reduce patient infectivity. Conceptual ideas based on direct plasma jet application to the mucosal tissue on the one hand or plasma‐treated aerosols or gases for inhalation purposes on the other are presented and discussed with respect to current knowledge on the antiviral effectivity of plasma treatment.
This paper presents the results of an experiment on the effect of the cold plasma (He+O2 or He+Air) pre-sowing stimulation of seeds of the Wolska cultivar of onion on the process of their germination. Four groups of seeds characterized by different exposure times (60, 120, 240 and 480 s) were used. Untreated seeds were used as a control. The distance between the electrode and the tested material was 50 mm. Pre-sowing plasma stimulation improved germination parameters such as germination capacity and germination energy for all the tested groups relative to the control. The highest fractions of germinated seeds were observed for an exposure time of 120 s. Analysis of the data showed a statistically significant impact of RF plasma on the seed germination parameters of the onion. SEM analysis showed that the interaction with plasma produced tension in the cells, leading to a change in their shape. No visible damage to the onion seed cells was observed, apart from the effect of depletion of the upper wax layer. The best influence on pathogenic fungi was when the group of seeds underwent 240 and 480 s of exposure to plasma fumigation, especially using the He+Air RF plasma jet.
The effluent remedy is ordinarily to allow human and commercial effluents to be disposed of whilst now no threat to human health or unacceptable damage to the natural ecosystem. Industrial effluents (in general from factories) comprise numerous substances, counting on the change. Industries have long discharged their effluents into close move courses, public sewers, and fields or the ocean, leading to environmental and fitness problems. Plasma is an innovative method to modify the properties of surface of material with atmospheric pressure. When electrical discharge takes place between the two electrodes the high intensity of plasma arc formed which produces highly active reactive radicals. Here, this paper represents the review of non-thermal plasma and its application, techniques and up to date undergoing development on the utilization of non-thermal plasma in numerous industrial wastewater treatment.
Objective
To evaluate whether atmospheric-pressure dielectric-barrier-discharge plasma treatment of zirconia enhances its biocompatibility with human gingival fibroblasts.
Materials and Methods
The zirconia disks were divided into four groups and treated using helium atmospheric-pressure dielectric-barrier-discharge plasmas for 30, 60 or 90 s or left untreated. The surface morphology, wettability and chemical elements were analyzed. Fibroblasts density, morphology, morphometry and attachment-related genes expression were measured at different time points from 3 to 72 h.
Results
After plasma treatment, the surface morphology and roughness remained the same, while the contact angle decreased from 78.31° to 43.71°, and the surface C/O ratio decreased from 3.17 to 0.89. The surficial areas and perimeters of HGFs were increased two-fold in the treated groups at 3 h. Fibroblasts density increased on treated disks at all time points, especially the ones treated for 60 s. Attachment-related genes in the groups treated for 30 and 60 s were significantly higher at 3 and 24 h.
Conclusion
The helium atmospheric-pressure dielectric-barrier-discharge plasma treatment enhances the biological behavior of fibroblasts on zirconia by increasing the expression of attachment-related genes within 24 h and promoting the cell density during longer culture times. Wettability of zirconia, an important physicochemical property, has a vital influence on the cell behaviors.
Atmospheric-pressure cold plasma was applied to process the surface of heat-polymerized acrylic resin. Changes to the physical properties and early adherence of Candida albicans were investigated. Alternating current cold plasma with Ar/O2 as working gas was used. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to study the possible mechanism. Experimental results showed that after plasma treatment, the contact angle of acrylic resin significantly decreased. There were no significant differences in roughness, flexural strength and elasticity modulus, but microhardness was significant improved in the treated group. More importantly, the early adherence of Candida albicans on the surface was reduced after plasma treatment. Cold plasma seemed to be a promising and convenient strategy of preventing the early adherence of Candida albicans on acrylic resins, which would greatly benefit potential dental applications.
Infection after shoulder surgery is rare but potentially devastating. Normal skin flora, including Staphylococcus aureus, Staphylococcus epidermidis, and Propionibacterium acnes, are the most commonly isolated pathogens. Perioperative measures to prevent infection are of paramount importance, and clinical acumen is necessary for diagnosis. Superficial infections may be managed with local wound measures and antibiotics; deep infections require surgical débridement in combination with antibiotic treatment. Treating physicians must make difficult decisions regarding antibiotic duration and the elimination of the offending organisms by resection arthroplasty, direct implant exchange, or staged revision arthroplasty. Eradication of a deep infection is usually successful, but the course of treatment is often protracted, and tissue destruction and scar may adversely affect functional outcome.
Radiofrequency low temperature plasma was used to mutate the strain B8 which can adsorb nickel ions, and the adsorptive ability of the mutant was tested. The experiments show that the optimum mutagenic conditions of B8 by plasma are as follows: the mutation time of 3 min, the mutation power of 50~65 W, the carrier gas of N2 and the carrier gas pressure of 20 Pa. The mutant Ni12 with high adsorptive ability was screened from the mutant strains of B8 mutated under above conditions, and the nickel ion adsorption capacity of the mutant Ni12 reaches 136.7 mg · g-1 (dry bacteria), which is 11.7% higher than that of raw strain B8. The genetic stability of mutant Ni12 can maintain in 5 generations. The mechanism study shows that the extra cellular polymer is an important factor affecting the adsorption of nickel ions. After the formation of mutant Ni12 biofilm on the porous ceramics, from solution with nickel ion concentration of 50 mg · L-1, the nickel ion adsorption ratio of Ni12 reaches 86%. The result of 16S rDNA sequence analysis indicates that the mutant Ni12 is Pseudomonas cedrina. The advantage of mutagenesis of raw strain B8 by radiofrequency low temperature plasma is its high efficiency, and the inheritance of mutant strain Ni12 is stable. Therefore, it has promising prospect of using it to treat the wastewater containing nickel ions.
This study evaluated the antifungal potential of low-temperature plasma (LTP) on a 72-hour Candida albicans biofilm. A growth inhibition zone test was conducted with agar plates inoculated with C. albicans and submitted to LTP and argon application at 3 and 10 mm for 10, 30, 60, 90, and 120 seconds. The groups for biofilm assays were 60 seconds of LTP application with a tip-to-sample distance of 3 mm (LTP-3) and 10 mm (LTP-10); –application of only argon gas for 60 seconds with a tip-to-sample distance of 3 mm (Ar-3) and 10 mm (Ar-10); and no treatment. The C. albicans biofilm was grown on saliva-coated discs. The medium was replaced every 24 hours. Confocal laser scanning microscopy revealed the proportion of live and dead cells, and variable pressure scanning electron microscopy (VPSEM) showed biofilm/cell structure. No inhibition zone was observed for control and either Ar groups. For the LTP groups, a progressively increasing of inhibition zone diameter was observed for different treatment durations. The LTP-3 and LTP-10 groups presented higher proportions of dead cells compared with the Ar-3 and Ar-10 groups. VPSEM revealed cell perforations in the LTP-3 and LTP-10 groups. A short period of LTP exposure demonstrated an antifungal effect on C. albicans biofilm.
Background:
Cold atmospheric plasma(CAP) have shown promises for wound healing though little is understood of underpinning mechanisms. Little has been reported so far of their potential treatment of immune-mediated diseases such as psoriasis.
Objectives:
To study CAP-induced cell death and in cytokine release of human keratinocytes as a first assessment of possible CAP use for psoriasis.
Methods:
Using a CAP generator free of energetic ions, we observed its effects on keratinocytes in morphology, cell viability and apoptosis, intracellular and mitochondrial ROS, lysosomal integrity and mitochondrial membrane potential, and on secretion and expression of eight cytokines at protein and gene level.
Results:
CAP induced reduced cell viability, apoptotic death, and production of intracellular and mitochondrial ROS in a dose-dependent matter. Mitochondrial dysfunction and lysosomal leakage were found in CAP treated cells. It also induced release of interleukin(IL)-6, IL-8, tumor necrosis factor(TNF)-α and vascular endothelial growth factor(VEGF), and enhanced the mRNA expression of IL-1β, IL-6, IL-8, IL-10, TNF-α, IFN-γ and VEGF. By contrast, IL-12 declined monotonically.
Conclusions:
The results suggest that with appropriate control of its dose physical plasma could induce cell death via apoptotic pathway and enable simultaneous reduction in IL-12. These may be used to suppress keratinocyte hyperproliferation and to target T cell activation for controlling amplification of inflammation, respectively. This provides an initial basis for further studies of CAP as potential therapeutics for inflammatory and immune-related diseases in dermatology including psoriasis. This article is protected by copyright. All rights reserved.
Motivated by the frequent microbial contamination of granular food products like cereal grains or sprout seeds, an atmospheric pressure dielectric barrier discharge (DBD) was developed to study plasma inactivation of microorganisms on granular materials. Wheat grains as well as polypropylene model substrates were artificially contaminated with endospores of Geobacillus stearothermophilus as a model organism and treated in a pulsed argon plasma discharge applying different combinations of treatment time, pulse voltage and frequency. While the treatment of polypropylene substrates resulted in an efficient reduction of microbes, wheat grains, having a rough surface and a deep ventral furrow, turned out to be more challenging to decontaminate. However, an improvement in treatment efficiency could be achieved by applying longer treatment, faster pulse frequency or higher pulse voltage. Furthermore, experiments demonstrated that endospore reduction was not caused by thermal, mechanical or electrical stress factors, but a direct effect of plasma-generated species, and chemical sputtering is supposed to be the predominant inactivation mechanism. Finally, it could be shown that functional wheat grain properties (Falling number, gluten content) are not negatively affected by our plasma treatment.
To investigate the dose-dependent effects of neutral oxygen radicals on the proliferation as well as the inactivation of microorganisms, we treated
suspensions of budding yeast cells with oxygen radicals using an atmospheric-pressure oxygen radical source, varying the fluxes of O(3Pj) from 1.3 × 1016 to 2.3 × 1017 cm−2 s−1. Proliferation was promoted at doses of O(3Pj) ranging from 6 × 1016 to 2 × 1017 cm−3, and suppressed at doses ranging from 3 × 1017 to 1 × 1018 cm−3; cells were inactivated by O(3Pj) doses exceeding 1 × 1018 cm−3, even when the flux was varied over the above flux range. These results showed that the growth of cells was regulated primarily in response to the total dose of O(3Pj).
Pharmaceutical compounds became an important class of water pollutants due to their increasing consumption over the last years, as well as due to their persistence in the environment. Since conventional waste water treatment plants are unable to remove certain non-biodegradable pharmaceuticals, advanced oxidation processes was extensively studied for this purpose. Among them, non-thermal plasma was also recently investigated and promising results were obtained. This work reviews the recent research on the oxidative degradation of pharmaceuticals using non-thermal plasma in contact with liquid. As target compounds, several drugs belonging to different therapeutic groups were selected: antibiotics, anticonvulsants, anxiolytics, lipid regulators, vasodilatators, contrast media, antihypertensives and analgesics. It was found that these compounds were removed from water relatively fast, partly degraded, and partly even mineralized. In order to ensure the effluent is environmentally safe it is important to identify the degradation intermediates and to follow their evolution during treatment, which requires complex chemical analysis of the solutions. Based on this analysis, degradation pathways of the investigated pharmaceuticals under plasma conditions were suggested. After sufficient plasma treatment the final organic by-products present in the solutions were mainly small molecules in an advanced oxidation state.
Anthropogenic pollutants and in particular pharmaceutical residues are a potential risk for potable water where they are found in increasing concentrations. Different environmental effects could already be linked to the presence of pharmaceuticals in surface waters even for low concentrations. Many pharmaceuticals withstand conventional water treatment technologies. Consequently, there is a need for new water purification techniques. Advanced oxidation processes (AOP), and especially plasmas with their ability to create reactive species directly in water, may offer a promising solution. We developed a plasma reactor with a coaxial geometry to generate large volume corona discharges directly in water and investigated the degradation of seven recalcitrant pharmaceuticals (carbamazepine, diatrizoate, diazepam, diclofenac, ibuprofen, 17α-ethinylestradiol, trimethoprim). For most substances we observed decomposition rates from 45% to 99% for treatment times of 15-66 min. Especially ethinylestradiol and diclofenac were readily decomposed. As an inherent advantage of the method, we found no acidification and only an insignificant increase in nitrate/nitrite concentrations below legal limits for the treatment. Studies on the basic plasma chemical processes for the model system of phenol showed that the degradation is primarily caused by hydroxyl radicals.
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