Application Of Non-thermal Plasma Research Articles

Effect of Transient Spark Discharge and Plasma Activated Water Treatments against Fusarium graminearum Infected Wheat Grains under Laboratory Conditions

AbstractOver the last decade, more and more attention has been paid to applications of non-thermal plasma in agriculture, where it is used to decontaminate various microorganisms and to improve the seed germination. In this study, we present the results of a newly developed point-to-ring NTP transient spark discharge apparatus (NTP), plasma activated water (PAW) and their combined treatment on Durum wheat and Common wheat grains under laboratory conditions. Transient spark discharge treatment was used as direct treatment while indirect treatment of wheat grains was performed by PAW produced in point-to-plane NTP transient spark apparatus. We found that the degree of grain surface decontamination was in order NTP > PAW > combined treatment. In the case of Durum wheat grain germination, all treatments increased germination with increasing exposure times, while in the case of Common wheat, PAW treatment and combined treatment did not significantly increase the grain germination. In conclusion, plasma treatment has enormous potential for use in agriculture and its possibilities need to be fully explored.

Non-Thermal Plasma Reduces HSV-1 Infection of and Replication in HaCaT Keratinocytes In Vitro.

Herpes simplex virus type 1 (HSV-1) is a lifelong pathogen characterized by asymptomatic latent infection in the trigeminal ganglia (TG), with periodic outbreaks of cold sores caused by virus reactivation in the TG and subsequent replication in the oral mucosa. While antiviral therapies can provide relief from cold sores, they are unable to eliminate HSV-1. We provide experimental results that highlight non-thermal plasma (NTP) as a new alternative therapy for HSV-1 infection that would resolve cold sores faster and reduce the establishment of latent infection in the TG. Additionally, this study is the first to explore the use of NTP as a therapy that can both treat and prevent human viral infections. The antiviral effect of NTP was investigated using an in vitro model of HSV-1 epithelial infection that involved the application of NTP from two separate devices to cell-free HSV-1, HSV-1-infected cells, and uninfected cells. It was found that NTP reduced the infectivity of cell-free HSV-1, reduced viral replication in HSV-1-infected cells, and diminished the susceptibility of uninfected cells to HSV-1 infection. This triad of antiviral mechanisms of action suggests the potential of NTP as a therapeutic agent effective against HSV-1 infection.

Nonthermal Atmospheric Pressure Plasma Treatment of Endosteal Implants for Osseointegration and Antimicrobial Efficacy: A Comprehensive Review.

The energy state of endosteal implants is dependent on the material, manufacturing technique, cleaning procedure, sterilization method, and surgical manipulation. An implant surface carrying a positive charge renders hydrophilic properties, thereby facilitating the absorption of vital plasma proteins crucial for osteogenic interactions. Techniques to control the surface charge involve processes like oxidation, chemical and topographical adjustments as well as the application of nonthermal plasma (NTP) treatment. NTP at atmospheric pressure and at room temperature can induce chemical and/or physical reactions that enhance wettability through surface energy changes. NTP has thus been used to modify the oxide layer of endosteal implants that interface with adjacent tissue cells and proteins. Results have indicated that if applied prior to implantation, NTP strengthens the interaction with surrounding hard tissue structures during the critical phases of early healing, thereby promoting rapid bone formation. Also, during this time period, NTP has been found to result in enhanced biomechanical fixation. As such, the application of NTP may serve as a practical and reliable method to improve healing outcomes. This review aims to provide an in-depth exploration of the parameters to be considered in the application of NTP on endosteal implants. In addition, the short- and long-term effects of NTP on osseointegration are addressed, as well as recent advances in the utilization of NTP in the treatment of periodontal disease.

Liquid plasma promotes angiogenesis through upregulation of endothelial nitric oxide synthase-induced extracellular matrix metabolism: potential applications of liquid plasma for vascular injuries

BackgroundApplications of nonthermal plasma have expanded beyond the biomedical field to include antibacterial, anti-inflammatory, wound healing, and tissue regeneration. Plasma enhances epithelial cell repair; however, the potential damage to deep tissues and vascular structures remains under investigation.ResultThis study assessed whether liquid plasma (LP) increased nitric oxide (NO) production in human umbilical vein endothelial cells by modulating endothelial NO synthase (eNOS) phosphorylation and potential signaling pathways. First, we developed a liquid plasma product and confirmed the angiogenic effect of LP using the Matrigel plug assay. We found that the NO content increased in plasma-treated water. NO in plasma-treated water promoted cell migration and angiogenesis in scratch and tube formation assays via vascular endothelial growth factor mRNA expression. In addition to endothelial cell proliferation and migration, LP influenced extracellular matrix metabolism and matrix metalloproteinase activity. These effects were abolished by treatment with NG-L-monomethyl arginine, a specific inhibitor of NO synthase. Furthermore, we investigated the signaling pathways mediating the phosphorylation and activation of eNOS in LP-treated cells and the role of LKB1-adenosine monophosphate-activated protein kinase in signaling. Downregulation of adenosine monophosphate-activated protein kinase by siRNA partially inhibited LP-induced eNOS phosphorylation, angiogenesis, and migration.ConclusionThe present study suggests that LP treatment may be a novel strategy for promoting angiogenesis in vascular damage.A1BBJsagnHJAo-Bf8DXnP6Video Graphical

Application of Direct and Indirect Non-thermal Plasma in the Development of Ready-to-Eat Foods

Application of Direct and Indirect Non-thermal Plasma in the Development of Ready-to-Eat Foods

Harnessing Non-Thermal Plasma to Supercharge Recovery in Abdominal Surgeries: A Pilot Study.

(1) Background: This study aims to evaluate the efficacy and safety of non-thermal plasma (NTP) therapy in accelerating wound healing in patients who have undergone laparoscopic and open surgeries. (2) Methods: NTP was applied using a needle-type reactor with an irradiance of 0.5 W/cm2 on the surgical wounds of fifty patients after obtaining informed consent. Three NTP treatments, each lasting three minutes, were administered hourly. (3) Results: The pilot study showed that NTP-treated surgical wounds healed completely without any signs of infection, dehiscence, pain, or itching. Notably, patients reported minimal pain after the NTP treatment. Visual assessments conducted twenty-four hours after surgery revealed no redness or fluid discharge. Comparisons with traditionally sutured wounds indicated that NTP-treated wounds healed at a rate equivalent to seven days. (4) Conclusions: The application of NTP in laparoscopic and open wounds proved safe and effective, expediting the wound healing process and eliminating clinical risks post-surgery. Significantly, NTP facilitated a healing rate within twenty-four hours, equivalent to seven days for suture-treated wounds, significantly reducing the hospitalization time to a single day. These findings highlight the potential of NTP to be a transformative approach for promoting postoperative recovery.

Non-thermal plasma promotes boar sperm quality through increasing AMPK methylation

Boar sperm quality, as an important indicator of reproductive efficiency, directly affects the efficiency of livestock production. Here, this study was conducted to improve the boar sperm quality by using a non-thermal dielectric barrier discharge (DBD) plasma. Our results showed that DBD plasma exposure at 2.1 W for 15 s could improve boar sperm quality by increasing exon methylation level of adenosine monophosphate-activated protein kinase (AMPK) and thus improving the glycolytic flux, mitochondrial function, and antioxidant capacity without damaging the integrity of sperm DNA and acrosome. In addition, DBD plasma could rescue DNA methyltransferase inhibitor decitabine-caused low sperm quality through reducing the oxidative stress and mitochondrial damage. Therefore, the application of non-thermal plasma provides a new strategy for reducing sperm oxidative damage and improving sperm quality, which shows a great potential in assisted reproduction to solve the problem of male infertility.

Effects and Mechanisms of Non-Thermal Plasma-Mediated ROS and Its Applications in Animal Husbandry and Biomedicine.

Non-thermal plasma (NTP) is an ionized gas composed of neutral and charged reactive species, electric fields, and ultraviolet radiation. NTP presents a relatively low discharge temperature because it is characterized by the fact that the temperature values of ions and neutral particles are much lower than that of electrons. Reactive species (atoms, radicals, ions, electrons) are produced in NTP and delivered to biological objects induce a set of biochemical processes in cells or tissues. NTP can mediate reactive oxygen species (ROS) levels in an intensity- and time-dependent manner. ROS homeostasis plays an important role in animal health. Relatively low or physiological levels of ROS mediated by NTP promote cell proliferation and differentiation, while high or excessive levels of ROS mediated by NTP cause oxidative stress damage and even cell death. NTP treatment under appropriate conditions not only produces moderate levels of exogenous ROS directly and stimulates intracellular ROS generation, but also can regulate intracellular ROS levels indirectly, which affect the redox state in different cells and tissues of animals. However, the treatment condition of NTP need to be optimized and the potential mechanism of NTP-mediated ROS in different biological targets is still unclear. Over the past ten decades, interest in the application of NTP technology in biology and medical sciences has been rapidly growing. There is significant optimism that NTP can be developed for a wide range of applications such as wound healing, oral treatment, cancer therapy, and biomedical materials because of its safety, non-toxicity, and high efficiency. Moreover, the combined application of NTP with other methods is currently a hot research topic because of more effective effects on sterilization and anti-cancer abilities. Interestingly, NTP technology has presented great application potential in the animal husbandry field in recent years. However, the wide applications of NTP are related to different and complicated mechanisms, and whether NTP-mediated ROS play a critical role in its application need to be clarified. Therefore, this review mainly summarizes the effects of ROS on animal health, the mechanisms of NTP-mediated ROS levels through antioxidant clearance and ROS generation, and the potential applications of NTP-mediated ROS in animal growth and breeding, animal health, animal-derived food safety, and biomedical fields including would healing, oral treatment, cancer therapy, and biomaterials. This will provide a theoretical basis for promoting the healthy development of animal husbandry and the prevention and treatment of diseases in both animals and human beings.

A surface dielectric barrier discharge reactor for biological treatments

Antimicrobial plasma effects are promising for therapeutic applications like wound healing, cancer/tumor treatment, or pathogen-associated skin or dental diseases, but also in hygiene, food, and agriculture processing. Dielectric Barrier Discharge (DBD) reactors are the most widely used systems for antimicrobial purposes because they can use atmospheric air as a gas, do not require a vacuum, and are simple, inexpensive, and easy to use. However, when DBD plasma is applied directly to the biological sample, discharge current may pass through the biological sample, causing the plasma to transit to spark discharge and thus causing damage to the biological sample. Since Surface Dielectric Barrier Discharge (SDBD) plasmas can be generated far from the sample, they offer great advantages in the application of non-thermal plasma in extremely large volumes. While SDBD plasmas are generally generated on the lid of the container in which the sample is placed and the plasma species are expected to reach the sample, in this study, SDBD plasmas were produced on the container itself. A new SDBD reactor that can be applied to samples of various sizes and properties for antimicrobial purposes was manufactured. Gram-negative E. coli, gram-positive S. aureus and E. faecalis planktonic bacteria were placed in the reactor and inactivated for 10 min by exposure to non-thermal plasma. A plasma sterilization unit with 31.4 W power, practical, user-friendly, developed for bio-applications, with a 6.2-liter capacity.

Effect of Plasma-Activated Time for Ozone Generation in SDBD System Under Pulse and Sinusoidal Excitation

In the surface dielectric barrier discharge (SDBD) excitation schema, different power source topologies, such as the pulse and sinusoidal voltage inverters, are used to obtain the plasma. The inverter design is a critical element for consumer applications. However, some works in the literature have explained plasma properties and high-voltage excitation, but no clear definition has been identified to select a plasma property for a particular application. In general, SDBD is used for nonthermal plasma applications such as air purification and sterilization. Plasma generates reactive species that can react with target substances. Therefore, the reactive species generation rate greatly affects the plasma reaction performance. In addition, some researchers compare the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{O}_3$</tex-math> </inline-formula> generation rate with sinusoidal and pulse power supply, but they do not focus enough on the plasma which determines the electrical properties. In this study, the plasma-activated time (PAT) is introduced to link the plasma properties and electrical parameters. Sinusoidal and pulse voltage excitation characteristics and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{O}_3$</tex-math> </inline-formula> generation rates are used to experiment with this concept. The generation of reactive species is tested by measuring the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{O}_3$</tex-math> </inline-formula> generation rate under fixed electrical and environmental conditions such as voltage, temperature, humidity, frequency, and PAT.

Role of Experimental, Modeling, and Simulation Studies of Plasma in Sustainable Green Energy

This comprehensive review paper offers a multifaceted examination of non-thermal plasma applications in addressing the complex challenge of tar removal within biomass-oriented technologies. It begins with a concise introduction to the research background, setting the context for our exploration. The research framework is then unveiled, providing a structured foundation for understanding the intricate dynamics of plasma–tar interactions. As we delve deeper into the subject, we elucidate the reactivity of tar compounds and the transformation of alkali metals through plasma-based methodologies, essential factors in enhancing product gas quality. Through an array of empirical studies, we investigated the nuanced interactions between plasma and diverse materials, yielding crucial insights into plasma kinetics, modeling techniques, and the optimization of plasma reactors and processes. Our critical review also underscores the indispensable role of kinetic modeling and simulation in advancing sustainable green energy technologies. By harnessing these analytical tools, researchers can elevate system efficiency, reduce emissions, and diversify the spectrum of available renewable energy sources. Furthermore, we delve into the intricate realm of modeling plasma behavior and its intricate interplay with various constituents, illuminating a path toward innovative plasma-driven solutions. This comprehensive review highlights the significance of holistic research efforts that encompass empirical investigations and intricate theoretical modeling, collectively advancing the frontiers of plasma-based technologies within the dynamic landscape of sustainable energy. The insights gained from this review contribute to the overall understanding of plasma technologies and their role in achieving a greener energy landscape.

Non-thermal plasma radiation-induced changes in antibiotic susceptibility and protein profile of Staphylococcus aureus.

Plasma radiation is a widely used technique for sterilization or decontamination in various industries, as well as in some healthcare settings such as dentistry. The primary aim of this study was to assess the potential of plasma radiation to create a new population of Staphylococcus aureus cells with distinct characteristics that could lead to novel healthcare challenges. A homemade non-thermal plasma apparatus was applied and the effects of plasma treatment on S. aureus ATCC25923 was assessed. Plasma radiation was applied under controlled conditions to ensure that some bacterial cells remained viable. The treatment was repeated 10 times, with each round followed by a recovery phase to collect any surviving bacterial cells. To assess the potential changes in the bacterial population, we examined the antibiotic susceptibility pattern, micro-structural characteristics using scanning electron microscopy (SEM), and total protein profile using the matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) technique. The experimental results revealed slight variations in the antibiotic susceptibility patterns of certain cell wall agents (imipenem, cephalothin, and cefepime), as well as in the MALDI-TOF spectra. However, no changes were observed in the SEM images. The insufficient application of non-thermal plasma in bacterial decontamination may lead to physiological changes that could enrich or select certain subpopulations of S. aureus.

Non-Thermal Plasma Application in Medicine-Focus on Reactive Species Involvement.

Non-thermal plasma (NTP) application in medicine is a dynamically developing interdisciplinary field. Despite the fact that basics of the plasma phenomenon have been known since the 19th century, growing scientific attention has been paid in recent years to the use of plasma in medicine. Three most important plasma-based effects are pivotal for medical applications: (i) inactivation of a broad spectrum of microorganisms, (ii) stimulation of cell proliferation and angiogenesis with lower plasma treatment intensity, and (iii) inactivation of cells by initialization of cell death with higher plasma intensity. In this review, we explain the underlying chemical processes and reactive species involvement during NTP in human (or animal) tissues, as well as in bacteria inactivation, which leads to sterilization and indirectly supports wound healing. In addition, plasma-mediated modifications of medical surfaces, such as surgical instruments or implants, are described. This review focuses on the existing knowledge on NTP-based in vitro and in vivo studies and highlights potential opportunities for the development of novel therapeutic methods. A full understanding of the NTP mechanisms of action is urgently needed for the further development of modern plasma-based medicine.

Tetrachloroaurate (III)–induced oxidation increases nonthermal plasma-induced aldehydes

Research on nonthermal plasma (NTP) devices first began almost five decades ago. NTP devices discharge electrons, positive ions, ultraviolet light, reactive oxygen species (ROS) and reactive nitrogen species (RNS) at near-physiological temperatures. Advances in plasma science have enabled the manipulation of ROS/RNS irradiation for medical applications. During preclinical stages and in human clinical trials, NTP promotes blood coagulation, eradication of bacterial, viral, and biofilm-related infections, wound healing, and cancer therapy. Previously, tetrachloroaurate (III) increased NTP-induced oxidative stress that was attenuated by reduced and oxidized glutathione, indicating that the presence of interactions between metal ions and biomolecules may modulate biological effects. In this study, using 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO) as a spin probe in electron paramagnetic resonance (EPR), we observed that the tetrachloroaurate-induced M4PO-X spin adduct was significantly suppressed by ascorbate and α-tocopherol, while dehydroascorbate (DHA) and Trolox were ineffective. Tetrachloroaurate-induced lipid peroxidation, which was measured by 2-thiobarbituric acid-reactive substances (TBARS) in combination with NTP exposure, was suppressed by ascorbate, α-tocopherol and Trolox, while DHA was ineffective. Furthermore, N-acetyl-l-cysteine and dithiothreitol efficiently suppressed tetrachloroaurate-induced M4PO-X spin adduct and lipid peroxidation. LC‒MS/MS analyzes identified hexanal that was significantly elevated by NTP exposure and/or tetrachloroaurate. However, 25 and 250 μM ascorbate did not significantly suppress the formation of aldehydes, such as acetaldehyde, hexanal, nonanal, nonenal, and 4‑hydroxy-2-nonenal. Further studies are warranted to elucidate the redox reactions between metal ions, including gold (III), and biomolecules to expand the possibility of NTP application in medicine and agriculture.

Efficient modeling of electron kinetics under influence of externally applied electric field in magnetized weakly ionized plasma

We present a theory based on the conventional two-term (i.e. Lorentzian) approximation to the exact solution of the Boltzmann equation in non-magnetized weakly ionized plasma to efficiently obtain the electron rate and transport coefficients in a magnetized plasma for an arbitrary magnitude and direction of applied electric field and magnetic field . The proposed transcendental method does not require the two-term solution of the Boltzmann equation in magnetized plasma, based on which the transport parameters vary as a function of the reduced electric field , reduced electron cyclotron frequency , and angle between and vectors, where N is the density of neutrals. Comparisons between the coefficients derived from BOLSIG+’s solution (obtained via the two-term expansion when ) and coefficients of the presented method are illustrated for air, a mixture of molecular hydrogen (H2) and helium (He) representing the giant gas planets of the Solar System, and pure carbon dioxide (CO2). The new approach may be used in the modeling of magnetized plasma encountered in the context of transient luminous events, e.g. sprite streamers in the atmosphere of Earth and Jupiter, in modeling the propagation of lightning’s electromagnetic pulses in Earth’s ionosphere, and in various laboratory and industrial applications of nonthermal plasmas.

Nonthermal plasma coupled with liquid-phase UV/Fe–C for chlorobenzene removal

Catalyst poisoning problems limit the application of gas-solid non-thermal plasma (NTP) catalyzed decomposition of chlorinated volatile organic compounds (Cl–VOCs). To mitigate the catalyst deactivation, catalyst iron-loaded activated carbon (Fe–C) was added to the UV-activated liquid phase downstream of the NTP reactor (NTP + UV/Fe–C(L)) for the degradation of chlorobenzene (CB) in this study. The CB removal efficiency and mineralization efficiency (MR) of NTP + UV/Fe–C(L) were up to 94% and 68%, respectively, which were increased by 39% and 30% compared with the single NTP system. Compared with the conventional gas-solid NTP + UV/Fe–C(S) system, the stability of the NTP + UV/Fe–C(L) system was significantly improved due to the dissolved organic intermediates and low residuals on the catalyst surface. Reactive oxygen species ·OH and ·O2− dominated the decomposition of CB in the liquid phase, and with the help of UV, much more ·OH and ·O2− were produced by Fe–C catalytic O3. In addition, Fe–C improved the removal of CB by increasing its absorption mass transfer coefficient from 0.0016 to 0.0157 s−1. The degradation pathway of CB in the NTP + UV/Fe–C(L) system was proposed based on the detected organic intermediates. Overall, this study provides a new tactic to solve the catalyst poisoning problem in the NTP catalytic oxidation of Cl–VOCs.

Influence of Non-Thermal Plasma Treatment on Structural Network Attributes of Wheat Flour and Respective Dough.

Due to its "generally recognized as safe status" (GRAS) and moderate treatment temperatures, non-thermal plasma (NTP) has lately been considered a suitable replacement for chemicals in the modification of food properties and for preserving food quality. One of the promising areas for the application of NTP is the treatment of wheat flour, leading to improved flour properties and product quality and consequently to higher customer satisfaction. In the present research, the German wheat flour type 550, equivalent to all-purpose flour, was treated using NTP in a rotational reactor to determine the influence of short treatment times (≤5 min) on the properties of flour (moisture and fat content, protein, starch, color, microbial activity, and enzymes), dough (visco-elastic properties, starch, wet and dry gluten, and water absorption), and baking products (color, freshness, baked volume, crumb structure, softness, and elasticity). Based on the properties of NTP, it was expected that even very short treatment times would have a significant effect on the flour particles, which could positively affect the quality of the final baking product. Overall, the experimental analysis showed a positive effect of NTP treatment of wheat flour, e.g., decreased water activity value (<0.7), which is known to positively affect flour stability and product shelf life; dough stability increased (>8% after 5 min. treatment); dough extensibility increased (ca. 30% after 3 min treatment); etc. Regarding the baking product, further positive effects were detected, e.g., enhanced product volume (>9%), improved crumb whiteness/decreased crumb yellowness, softening of breadcrumb without a change in elasticity, and limited microorganism and enzymatic activity. Furthermore, no negative effects on the product quality were observed, even though further food quality tests are required. The presented experimental research confirms the overall positive influence of NTP treatment, even for very low treatment times, on wheat flour and its products. The presented findings are significant for the potential implementation of this technique on an industrial level.

Review on the Biomedical and Environmental Applications of Nonthermal Plasma

Recent advances in atmospheric plasmas have led to the formation of nonthermal plasma (NTP). In recent decades, a number of novel plasma diagnostic approaches have been implemented and reported in order to better understand the physics of NTP. The use of NTP is a novel approach to producing reactive oxygen and nitrogen species. Plasma technology has many applications, including electrical device microfabrication, biomedicine, dentistry, agriculture, ozone generation, chemical synthesis, surface treatment, coating, and disease therapy. Furthermore, NTP is thought to be a successful strategy for the degradation of hazardous pollutants in the environment, making it a future hope. Recent studies showed that various operating parameters affect the yield of NTP-based technology. Especially, the presence of a catalyst, properly placed in an NTP reactor, leads to a significant increase in process performance as compared to NTP alone. Scientists have looked at using NTP in conjunction with catalysts to remove various sorts of pollutants from the environment. In this context, review articles are crucial due to the prevalence of NTP-based applications and ongoing developments. This review will describe recent advancements in NTP-based biomedical applications, bacterial inactivation, food preservation and storage, and environmental catalytic formulations. This review could be useful in providing a platform for advancements in biological applications and environmental protection through the use of NTP technology.

Determination of the apparent effective ionization coefficient in mixtures of He and O2 using steady-state Townsend discharge: effect of penning ionization and attachment

He:O2 gas mixtures are popular in many non-thermal plasma applications because of the good thermal conductivity of He and high production of reactive oxygen species. The applications utilizing reactive oxygen species, in particular, applications in biomedicine require accurate knowledge of the fundamental ionization parameters of gases such as the ionization coefficient. This study was focused on experimental determination of the reduced apparent effective ionization coefficient α ea /N in He:O2 mixtures. Experiments were conducted in the absolute pressure range of 10–800 Torr and reduced electric field E/N range of 40–1000 Td utilizing a steady-state non-self-sustaining Townsend discharge. Experimental results were compared with a theoretical model which was based on BOLSIG + calculation of ionization and attachment coefficients and additionally considered the ion conversion of O− to O2 −, detachment from O2 − and formation of O3 − and Penning ionization by He metastable species. The measurements agreed reasonably well with model calculations. Comparison with model suggest that He metastable species affect net ionization in He:O2 mixtures with O2 concentrations up to 10% often encountered in the applications and thus should be included in models of atmospheric pressure plasmas. The attachment of electrons became important at O2 concentrations above 10% and is therefore less important in most applications.

Manipulation of Oxidative Stress Responses by Non-Thermal Plasma to Treat Herpes Simplex Virus Type 1 Infection and Disease

Herpes simplex virus type 1 (HSV-1) is a contagious pathogen with a large global footprint, due to its ability to cause lifelong infection in patients. Current antiviral therapies are effective in limiting viral replication in the epithelial cells to alleviate clinical symptoms, but ineffective in eliminating latent viral reservoirs in neurons. Much of HSV-1 pathogenesis is dependent on its ability to manipulate oxidative stress responses to craft a cellular environment that favors HSV-1 replication. However, to maintain redox homeostasis and to promote antiviral immune responses, the infected cell can upregulate reactive oxygen and nitrogen species (RONS) while having a tight control on antioxidant concentrations to prevent cellular damage. Non-thermal plasma (NTP), which we propose as a potential therapy alternative directed against HSV-1 infection, is a means to deliver RONS that affect redox homeostasis in the infected cell. This review emphasizes how NTP can be an effective therapy for HSV-1 infections through the direct antiviral activity of RONS and via immunomodulatory changes in the infected cells that will stimulate anti-HSV-1 adaptive immune responses. Overall, NTP application can control HSV-1 replication and address the challenges of latency by decreasing the size of the viral reservoir in the nervous system.