Plasma-activated water: An alternative disinfectant for S protein inactivation to prevent SARS-CoV-2 infection

Viral inactivation of murine coronavirus via multiple gas plasma-derived reactive species

The recent pandemic has highlighted the urgent need to elucidate the pathophysiological mechanisms underlying viral effects in humans and is driving the search for innovative antiviral therapies. Several studies have investigated the ability of gas plasma, a partially ionized gas that simultaneously generates several reactive species, to be a new antiviral tool. However, several aspects of the mechanisms of antiviral action of gas plasma remained elusive. In this study, we, for the first time, used a gas plasma device approved for medical purposes and routinely applied in the clinics, especially for wound healing, to test its antiviral activity against a murine corona-virus in vitro (MHV-GFP), a research model analogous to human coronaviruses such as SARS-CoV-2. For this, we established a novel high-content imaging assay that gave quantitative and kinetic information about infection and reduced viral activity in murine fibroblasts (17Cl-1) host cells. Gas plasma treatment delayed viral infectivity and reduced overall infection and toxicity in 17Cl1 cells. Various antioxidants at different concentrations were screened to identify ROS relevant to antiviral effects. Catalase provided no virus protection, and DMSO, mannitol, histidine, Trolox, and ascorbic acid only modestly reduced gas plasma virucidal efficacy. By contrast, glutathione, tyrosine, and cysteine showed profound but not complete protection of MHV from gas plasma-derived reactive species, suggesting pivotal roles of superoxide radicals and peroxynitrite gas in plasma-driven viral inactivation. At extended gas plasma exposure times, fewer intact MHV RNA were detected, indicative of reactive species-driven RNA modifications or degradation as an additional mechanism of action. Virus particle size changes measured by electron microscopy were moderate. Collectively, we identified the potent antiviral activity of a clinically approved argon plasma jet along with potential mechanisms of action.

Secondary activation on plasma-activated water by plasma-treated cotton for restoring and enhancing disinfection effect

Plasma-activated water (PAW) is a novel antimicrobial agent with negligible toxicity and environmental burden, holding promise as an alternative to chemical disinfectants and antibiotics. In practice, liquid disinfectants are often soaked with cotton materials before further use. Rich in reducing functional groups on the surface, cotton will inevitably react with PAW, leading to the deterioration of PAW's functions. To resolve this issue, this work proposes a new concept of "secondary activation" for retaining and enhancing PAW's bioactivity, i.e., pre-treating cotton with air plasma before soaking PAW. For the first time, we find that the PAW absorbed by raw cotton completely loses its bactericidal effect, while plasma-treated cotton (PTC) restores the disinfection capacity and prolongs its effective duration. This restoration is attributed to the absorption of plasma-generated reactive species by cotton with oxidizing and nitrifying modifications on the fiber surface. Consequently, the concentrations of aqueous species in PAW increase rather than decrease after absorption by PTC. In addition, the PTC after 28-day storage can still enable PAW to achieve a bacterial reduction of ∼3 logs. This work identifies and addresses a crucial limitation in the disinfection application of PAW and elucidates the mechanism underlying PTC production and secondary activation of PAW.

Inactivation of Pseudovirus Expressing the D614G Spike Protein Mutation using Nitric Oxide-Plasma Activated Water

Variants of concern (VOCs) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) exhibit high infectivity due to mutations, particularly in the spike protein, that facilitate enhanced binding of virus to human angiotensin-converting enzyme 2 (hACE2). The D614G mutation, situated in S1-domain, promotes the open conformation of spike protein, augmenting its interaction with hACE2. Activated water neutralizes pathogens by damaging biological molecules; however, its effect on mutated SARS-CoV-2 or VOCs requires further exploration. Here, the efficacy of nitric oxide (NOx)-plasma activated water (PAW) in inhibiting infections by SARS-CoV-2 pseudovirus expressing D614G-mutated spike protein is investigated, which serves as a model for mutated SARS-CoV-2. Results demonstrated high prevalence of D614G mutation in SARS-CoV-2 and its VOCs. NOx-PAW is non-toxic to cells at high concentration, inhibiting infection by 71%. Moreover, NOx-PAW induced structural changes in S1-domain of spike protein, reducing its binding affinity and lowering clathrin-mediated endocytosis-related gene expression. Additionally, in silico analysis revealed NOx species in NOx-PAW played key role in impairing S1-domain function of the mutated SARS-CoV-2 pseudovirus by interacting directly with it. Collectively, these findings reveal the potent inactivation ability of PAW against mutated SARS-CoV-2 and suggest its potential application in combating emerging variants of SARS-CoV-2 and other viral threats.

Plasma activated water pre-treatment substantially enhances phage activity against Proteus mirabilis biofilms

The ongoing antimicrobial resistance crisis has incentivised research into alternative antibacterial and antibiofilm agents. One of them is plasma-activated water (PAW), which is produced by exposing water to a cold plasma discharge. This process generates a diverse array of reactive oxygen and nitrogen species (ROS/RNS) with antimicrobial properties. Another intensively studied class of alternative antimicrobials are bacteriophages, attracting attention due to their specificity and strong antibacterial activity. As combinations of different types of antimicrobials are known to often exhibit synergistic interactions, in this study we investigated the combined use of cold atmospheric-pressure plasma-activated water and the bacteriophage vB_PmiS_PM-CJR against Proteus mirabilis biofilms as a potential option for treatment of catheter-associated urinary tract infections (CAUTIs). We compared the effect of two cold plasma discharge setups for PAW production on its antimicrobial efficacy against P. mirabilis planktonic and biofilm cultures. Next, we assessed the stability of the phage vB_PmiS_PM-CJR in PAW. Finally, we tested the antimicrobial activity of the phages and PAW against biofilms, both individually and in combinations. Our findings demonstrate that the combination of PAW with phage is more effective against biofilms compared to individual treatments, being able to reduce the number of biofilm-embedded cells by approximately 4 log. We were also able to show that the order of treatment plays an important role in the anti-biofilm activity of the phage-PAW combination, as the exposure of the biofilm to PAW prior to phage administration results in a stronger effect than the reverse order. This research underlines PAW's ability to potentiate phage activity, showcasing a considerable reduction in biofilm viability and biomass. Additionally, it contributes to the growing body of evidence supporting the use of phage-based combinatorial treatments. Overall, this sequential treatment strategy demonstrates the potential of leveraging multiple approaches to address the mounting challenge of antibiotic resistance and offers a promising avenue for enhancing the efficacy of CAUTI management.

Cold atmospheric plasma-activated saline alleviates secondary injury post-SCI by inhibiting extracellular matrix remodeling and infiltration of proinflammatory macrophages

BACKGROUND

Cold atmospheric plasma (CAP) has been shown to improve the recovery of transected peripheral nerves. We determined the protective role of CAP-activated saline (CAP-AS) treatment in the acute and subacute stages of spinal cord injury (SCI) in mice.

METHODS

C57BL/6 SCI mice were treated with CAP-AS for 14 days. Injury recovery was assessed weekly for four weeks by conducting motor function tests, including the Basso Mouse Scale (BMS) and footprint test. Transcriptome analysis was conducted on day 14 to elucidate potential mechanisms, which were further validated through immunofluorescence examinations of the injured spinal cord tissues on day 28 and the levels of proinflammatory cytokines produced by macrophages in vitro.

RESULTS

Compared to the SCI group, the CAP-AS-treated groups presented significantly better hindlimb motor function after four weeks. The downregulated (SCI vs. SCI + CAP-AS, with CAP-AS activated for 20 min) differentially expressed genes (DEGs) were enriched in the extracellular region, extracellular matrix (ECM), and ECM-receptor interaction. In contrast, the upregulated DEGs were enriched in immune response-associated pathways. Histological changes in the CAP-AS-treated groups were observed to further validate the predicted mechanisms 28 days post-injury. The alleviation of secondary injury was confirmed by an increase in GFAP-positive and NFH-positive areas, and enhanced outgrowth of 5-HT-positive fibers. Inhibited ECM remodeling was confirmed by a decrease in the areas positive for PDGFRβ, fibronectin, and laminin. A decrease in the infiltration of macrophages and activation of microglia was determined by a decrease in CD68-positive and F4/80-positive areas. The inhibitory effect of CAP-AS on inflammation was further supported by a decrease in the levels of the proinflammatory cytokines IL-1β, IL-6, and TNF-α in CAP-AS-treated M1 macrophages.

CONCLUSION

CAP-AS can alleviate secondary injury in SCI model mice by inhibiting ECM remodeling in injured tissues and reducing the infiltration or activation of proinflammatory macrophages/microglia.

Reactive species of plasma-activated water for murine norovirus 1 inactivation

Human norovirus (HuNoV), the leading cause of foodborne acute gastroenteritis, poses a serious threat to public health. Traditional disinfection methods lead to destructions of food properties and functions, and/or environmental contaminations. Green and efficient approaches are urgently needed to disinfect HuNoV. Plasma-activated water (PAW) containing amounts of reactive species is an emerging nonthermal and eco-friendly disinfectant towards the pathogenic microorganisms. However, the disinfection efficacy and mechanism of PAW on HuNoV has not yet been studied. Murine norovirus 1 (MNV-1) is one of the most commonly used HuNoV surrogates to evaluate the efficacy of disinfectants. In the current study, the inactivation efficacy of MNV-1 by PAW was investigated. The results demonstrated that PAW significantly inactivated MNV-1, reducing the viral titer from approximately 6 log10 TCID50/mL to non-detectable level. The decreased pH, increased oxidation-reduction potential (ORP) and conductivity of PAW were observed compared with that of deionized water. Compositional analysis revealed that hydrogen peroxide (H2O2), nitrate (NO3-) and hydroxyl radical (OH) were the functional reactive species in MNV-1 inactivation. L-histidine could scavenge most of the inactivation effect in a concentration-dependent manner. Moreover, PAW could induce damage to viral proteins. Part of MNV-1 particles was destroyed, while others were structurally intact without infectiousness. After 45 days of storage at 4 °C, PAW generated with 80 % O2 and 100 % O2 could still reduce over 4 log10 TCID50/mL of the viral titer. In addition, PAW prepared using hard water induced approximately 6 log10 TCID50/mL reduction of MNV-1. PAW treatment of MNV-1-inoculated blueberries reduced the viral titer from 3.79 log10 TCID50/mL to non-detectable level. Together, findings of the current study uncovered the crucial reactive species in PAW inactivate MNV-1 and provided a potential disinfection strategy to combat HuNoV in foods, water, and environment.

Nebulized inhalation of plasma-activated water in the treatment of progressive moderate COVID-19 patients with antiviral treatment failure: a randomized controlled pilot trial

BACKGROUND

Antiviral drugs show significant efficacy in non-severe COVID-19 cases, yet there remains a subset of moderate COVID-19 patients whose pneumonia continues to progress post a complete course of treatment. Plasma-activated water (PAW) possesses anti-SARS-CoV-2 properties. To explore the potential of PAW in improving pneumonia in COVID-19 patients following antiviral treatment failure, we conducted this study.

METHODS

This was a randomized, controlled trial. Moderate COVID-19 patients with antiviral treatment failure were randomly assigned to the experimental group or the control group. They inhaled nebulized PAW or saline respectively. This was done twice daily for four consecutive days. We assessed improvement in chest CT on day 5, the rate of symptom resolution within 10 days, and safety.

RESULTS

A total of 23 participants were included, with 11 receiving PAW and 12 receiving saline. The baseline characteristics of both groups were comparable. The experimental group showed a higher improvement rate in chest CT on day 5 (81.8% vs. 33.3%, p = 0.036). The cumulative disappearance rate of cough within 10 days was higher in the experimental group. Within 28 days, 4 patients in each group progressed to severe illness, and no patients died. No adverse reactions were reported from inhaling nebulized PAW.

CONCLUSION

This pilot trial preliminarily confirmed that nebulized inhalation of PAW can alleviate pneumonia in moderate COVID-19 patients with antiviral treatment failure, with no adverse reactions observed. This still needs to be verified by large-scale studies.

TRIAL REGISTRATION

Chinese Clinical Trial Registry; No.: ChiCTR2300078706 (retrospectively registered, 12/15/2023); URL: www.chictr.org.cn .

Plasma-activated water: Candidate hand disinfectant for SARS-CoV-2 transmission disruption

The global epidemic caused by SARS-CoV-2 has brought about worldwide burden and a sense of danger for more than two years, leading to a wide range of social, public health, economic and environmental issues. Self-inoculation through hands has been the primary way for environmental transmission of SARS-CoV-2. Plasma-activated water (PAW) has been reported as an effective, safe and environmentally friendly disinfectant against SARS-CoV-2. However, the inactivating effect of PAW on SARS-CoV-2 located on skin surface and its underlying mechanism of action have not been elucidated. In this study, PAW was prepared using an air-pressure plasma jet device. The antiviral efficiency of PAW1, PAW3, and PAW5 on the SARS-CoV-2 pseudovirus was 8.20 % (±2.88 %), 46.24 % (±1.79 %), and 91.71 % (±0.47 %), respectively. Additionally, determination of PAW's physicochemical properties, identification of major sterile effector in PAW, transmission electron microscopy analysis, malondialdehyde (MDA) assessment, SDS-PAGE, ELISA, and qPCR were conducted to reveal the virucidal mechanism of PAW. Our experimental results suggested that peroxynitrite, which was generated by the synergism of acidic environment and reactive species, was the major sterile effector of PAW. Furthermore, we found that PAW treatment significantly inactivated SARS-CoV-2 pseudovirus through the destruction of its structure of and the degradation of the viral RNA. Therefore, the possible mechanism for the structural destruction of SARS-COV-2 by PAW is through the action of peroxynitrite generated by the synergism of acidic environment and reactive species, which might react with and destroy the lipid envelope of SARS-CoV-2 pseudovirus. Nevertheless, further studies are required to shed light on the interaction mechanism of PAW-inherent RONS and viral components, and to confirm the determinant factors for virus inactivation of SARS-COV-2 by PAW. Therefore, PAW may be a candidate hand disinfectant used to disrupt the transmission of SARS-CoV-2.

Insights into the mechanisms of plasma physicochemical characteristics on ultralong-lasting plasma-activated water: the influence of DC power polarity on RONS generation

In our recent work, we successfully developed an innovative method based on pin-water discharge for preparing ultralong-lasting plasma-activated water (PAW) with a lifetime of up to 720 hours at room temperature. However, the impact of power polarity on the preparation method for ultralong-lasting PAW remains unclear. In this study, we discovered that ultralong-lasting PAW could only be achieved with positive polarity. Further analysis of the liquid reactive oxygen and nitrogen species (RONS) revealed that the absence of H2O2 in the discharge chamber was crucial for the failure of ultralong-lasting PAW preparation at negative polarity. To elucidate the mechanism underlying the generation of RONS at different polarities, we conducted plasma feature diagnosis, compared discharge morphologies, and performed theoretical analyses based on chemical reactions. Our results indicated that the introduction of water vapor molecules through intense spraying at positive polarity led to an increase in the generation of H2O2-related source particles, while also interfering with N2-related electron collision reactions and chemical reaction coefficients, ultimately affecting the production of NO2-. Consequently, there was relatively less liquid NO2- and more abundant H2O2 in the discharge chamber at positive polarity, whereas the opposite trend was observed for these two key RONS at negative polarity. Furthermore, the minimal amount of NO2- at positive polarity and the tiny amount of H2O2 at negative polarity in the discharge chamber would be respectively consumed by the relatively abundant H2O2 at positive polarity and NO2- at negative polarity.

Cold atmospheric plasma can effectively disinfect SARS-CoV-2 in the wastewater

COVID-19 is currently pandemic and the detection of SARS-CoV-2 variants in wastewater is causing widespread concern. Herein, cold atmospheric plasma (CAP) is proposed as a novel wastewater disinfection technology that effectively inactivates SARS-CoV-2 transcription- and replication-competent virus-like particles, coronavirus GX_P2V, pseudotyped SARS-CoV-2 variants, and porcine epidemic diarrhoea virus in a large volume of water within 180 s (inhibition rate > 99%). Further, CAP disinfection did not adversely affect the viability of various human cell lines. It is identified that CAP produced peroxynitrite (ONOO-), ozone (O3), superoxide anion radicals (O2 -), and hydrogen peroxide (H2O2) as the major active substances for coronavirus disinfection. Investigation of the mechanism showed that active substances not only reacted with the coronavirus spike protein and affected its infectivity, but also destroyed the nucleocapsid protein and genome, thus affecting virus replication. This method provides an efficient and environmentally friendly strategy for the elimination of SARS-CoV-2 and other coronaviruses from wastewater.

Inactivation mechanism of cold plasma combined with 222 nm ultraviolet for spike protein and its application in disinfecting of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible virus that has precipitated a worldwide pandemic of coronavirus disease since 2019. Developing an effective disinfection strategy is crucial to prevent the risk of surface cross-contamination by SARS-CoV-2. This study employed pseudovirus and the receptor-binding domain (RBD) protein of SARS-CoV-2 as models to investigate the spike protein inactivation process and its underlying mechanisms using a novel nonthermal technology. Cold plasma combined with 222 nm ultraviolet (CP+UV) treatment was applied to accelerate the generation of reactive species and enhance sterilization efficiency. The results indicated that the binding activity of RBD protein was completely inhibited at specific concentrations (0.01-0.05 mg/cm2) with corresponding treatment times of 15-30 s. The mechanism potentially involves the reactive species generated by CP+UV, which react with the spike protein RBD of SARS-CoV-2, leading to the loss of SARS-CoV-2 infectivity by causing damage to the β-sheet structure and chemical bonds in the RBD protein. Validated by a biosafety level 3 (BSL3) laboratory, the CP+UV treatment for 30 s could completely inactivate SARS-CoV-2 with a concentration of 19054 ± 1112 TCID50/cm2. Therefore, this study potentially provides a novel disinfection strategy for the inactivation of SARS-CoV-2 on surface cross-contamination.

Nanomaterials in Medicine: Understanding Cellular Uptake, Localization, and Retention for Enhanced Disease Diagnosis and Therapy

Nanomaterials (NMs) have emerged as promising tools for disease diagnosis and therapy due to their unique physicochemical properties. To maximize the effectiveness and design of NMs-based medical applications, it is essential to comprehend the complex mechanisms of cellular uptake, subcellular localization, and cellular retention. This review illuminates the various pathways that NMs take to get from the extracellular environment to certain intracellular compartments by investigating the various mechanisms that underlie their interaction with cells. The cellular uptake of NMs involves complex interactions with cell membranes, encompassing endocytosis, phagocytosis, and other active transport mechanisms. Unique uptake patterns across cell types highlight the necessity for customized NMs designs. After internalization, NMs move through a variety of intracellular routes that affect where they are located subcellularly. Understanding these pathways is pivotal for enhancing the targeted delivery of therapeutic agents and imaging probes. Furthermore, the cellular retention of NMs plays a critical role in sustained therapeutic efficacy and long-term imaging capabilities. Factors influencing cellular retention include nanoparticle size, surface chemistry, and the cellular microenvironment. Strategies for prolonging cellular retention are discussed, including surface modifications and encapsulation techniques. In conclusion, a comprehensive understanding of the mechanisms governing cellular uptake, subcellular localization, and cellular retention of NMs is essential for advancing their application in disease diagnosis and therapy. This review provides insights into the intricate interplay between NMs and biological systems, offering a foundation for the rational design of next-generation nanomedicines.

Atmospheric non-thermal plasma inactivation of Ascosphaera apis, the causative agent of chalkbrood disease in honeybee

Ascosphaera apis is a worldwide pathogenic fungi of honeybees that can cause a decline in bee populations. In this study, we investigated the antifungal activity of non-thermal plasma on fungal growth. Spore inactivation after exposure to gas plasma by liquid phase and plasma activated water (PAW) and pathogenicity of A. apis in vivo were also examined. The results demonstrated that the mycelial growth of fungi was completely inhibited after argon plasma treatment. Both gas plasma and PAW exposures resulted in a significant decrease of A. apis spore numbers, maximum reduction of 1.71 and 3.18-fold, respectively. Germinated fungal spores on potato dextrose agar were also reduced after plasma treatment. SEM analysis revealed a disruption in the morphological structure of the fungal spores. The pathogenicity of A. apis on honeybee larvae was decreased after spores treated by gas plasma and PAW with a disease inhibition of 63.61 ± 7.28% and 58.27 ± 5.87%, respectively after 7 days of cultivation. Chalkbrood in honey bees have limited control options and our findings are encouraging. Here, we demonstrate a possible alternative control method using non-thermal plasma for chalkbrood disease in honeybees.

Persistence of Coronavirus on Surface Materials and Its Control Measures Using Nonthermal Plasma and Other Agents

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been responsible for the initiation of the global pandemic since 2020. The virus spreads through contaminated air particles, fomite, and surface-contaminated porous (i.e., paper, wood, and masks) and non-porous (i.e., plastic, stainless steel, and glass) materials. The persistence of viruses on materials depends on porosity, adsorption, evaporation, isoelectric point, and environmental conditions, such as temperature, pH, and relative humidity. Disinfection techniques are crucial for preventing viral contamination on animated and inanimate surfaces. Currently, there are few effective methodologies for preventing SARS-CoV-2 and other coronaviruses without any side effects. Before infection can occur, measures must be taken to prevent the persistence of the coronavirus on the surfaces of both porous and non-porous inanimate materials. This review focuses on coronavirus persistence in surface materials (inanimate) and control measures. Viruses are inactivated through chemical and physical methods; the chemical methods particularly include alcohol, chlorine, and peroxide, whereas temperature, pH, humidity, ultraviolet irradiation (UV), gamma radiation, X-rays, ozone, and non-thermal, plasma-generated reactive oxygen and nitrogen species (RONS) are physical methods.

Effects of Nitro-Oxidative Stress on Biomolecules: Part 1-Non-Reactive Molecular Dynamics Simulations

Plasma medicine, or the biomedical application of cold atmospheric plasma (CAP), is an expanding field within plasma research. CAP has demonstrated remarkable versatility in diverse biological applications, including cancer treatment, wound healing, microorganism inactivation, and skin disease therapy. However, the precise mechanisms underlying the effects of CAP remain incompletely understood. The therapeutic effects of CAP are largely attributed to the generation of reactive oxygen and nitrogen species (RONS), which play a crucial role in the biological responses induced by CAP. Specifically, RONS produced during CAP treatment have the ability to chemically modify cell membranes and membrane proteins, causing nitro-oxidative stress, thereby leading to changes in membrane permeability and disruption of cellular processes. To gain atomic-level insights into these interactions, non-reactive molecular dynamics (MD) simulations have emerged as a valuable tool. These simulations facilitate the examination of larger-scale system dynamics, including protein-protein and protein-membrane interactions. In this comprehensive review, we focus on the applications of non-reactive MD simulations in studying the effects of CAP on cellular components and interactions at the atomic level, providing a detailed overview of the potential of CAP in medicine. We also review the results of other MD studies that are not related to plasma medicine but explore the effects of nitro-oxidative stress on cellular components and are therefore important for a broader understanding of the underlying processes.

Inhibition of Fungal Growth and Aflatoxin B1 Synthesis in Aspergillus flavus by Plasma-Activated Water

The gaseous reactive oxygen/nitrogen species (RONS) generated by cold atmospheric plasma (CAP) can effectively inactivate Aspergillus flavus (A. flavus) and prolong the shelf-life of food. Plasma-activated water (PAW) is the extension of cold plasma sterilization technology. Without the limitation of a plasma device, PAW can be applied to more scenarios of food decontamination. However, the efficacy of PAW as a carrier of RONS for eradicating A. flavus or inhibiting its growth remains unclear. In this study, the immediate fungicidal effect and long-term inhibitory effect of PAW on A. flavus were investigated. The results demonstrated that 60-min instant-prepared PAW could achieve a 3.22 log reduction CFU/mL of A. flavus and the fungicidal efficacy of PAW gradually declined with the extension of storage time. Peroxynitrite (ONOO^-/ONOOH) played a crucial role in this inactivation process, which could damage the cell wall and membrane structure, disrupt intracellular redox homeostasis, and impair mitochondrial function, ultimately leading to fungal inactivation. In addition to the fungicidal effect, PAW also exhibited fungistatic properties and inhibited the synthesis of aflatoxin B₁ (AFB₁) in A. flavus. By analyzing the cellular antioxidant capacity, energy metabolism, and key gene expression in the AFB₁ synthesis pathway, it was discovered that PAW can significantly reduce ATP levels, while increasing SOD and CAT activity during 5-d cultivation. Meanwhile, PAW effectively suppressed the expression of genes related to AFB₁ synthesis.

Solar desalination/purification (solar stills, humidification-dehumidification, solar disinfection) in high altitude during COVID19: Insights of gastrointestinal manifestations and systems' mechanism

From the starting of the pandemic different transmission routes of the pathogen was brought into the spotlight by researchers from different disciplines. This matter in high-altitudes was more boosted as the main parameters were not exactly realized. In this review we are about to highlight the possibility of consuming contaminated water generated form solar water desalination/disinfection systems in highlands. Three systems including solar still, solar disinfection (which experimented by the authors in 2019 in high altitude) and humidification-dehumidification were consider in this context. Ascribe to the risks of pathogens transmission in solar desalination/disinfection systems where the water resources are heavily polluted in every corner of the world, highlighting the risk of consuming water in high-altitude where there are many other parameters associated with spread of pathogen is of great importance. As it was reported, reliability of solar desalination and solar water disinfections systems against contaminated water by the novel coronavirus remained on the question because the virus can be transmitted by vapor in solar stills due to tiny particle size (60-140 nm) and would not be killed by solar disinfections due to low-temperature of operation <40 °C while for HDH contamination of both water and air by sars-cov-2 could be a concern. Although the SARS-CoV-2 is not a waterborne pathogen, its capability to replicate in stomach and infection of gastrointestinal glandular suggested the potential of transmission via fecal-oral. Eventually, it was concluded that using solar-based water treatment as drinking water in high altitude regions should be cautiously consider and recommendations and considerations are presented. Importantly, this critical review not only about the ongoing pandemic, but it aims is to highlight the importance of produced drinking water by systems for future epidemic/pandemic to prevent spread and entering a pathogen particularly in high-altitude regions via a new routes.

Plasma-Activated Hydrogels for Microbial Disinfection

A continuous risk from microbial infections poses a major environmental and public health challenge. As an emerging strategy for inhibiting bacterial infections, plasma-activated water (PAW) has proved to be highly effective, environmental-friendly, and non-drug resistant to a broad range of microorganisms. However, the relatively short lifetime of reactive oxygen and nitrogen species (RONS) and the high spreadability of liquid PAW inevitably limit its real-life applications. In this study, plasma-activated hydrogel (PAH) is developed to act as reactive species carrier that allow good storage and controlled slow-release of RONS to achieve long-term antibacterial effects. Three hydrogel materials, including hydroxyethyl cellulose (HEC), carbomer 940 (Carbomer), and acryloyldimethylammonium taurate/VP copolymer (AVC) are selected, and their antibacterial performances under different plasma activation conditions are investigated. It is shown that the composition of the gels plays the key role in determining their biochemical functions after the plasma activation. The antimicrobial performance of AVC is much better than that of PAW and the other two hydrogels, along with the excellent stability to maintain the antimicrobial activity for more than 14 days. The revealed mechanism of the antibacterial ability of the PAH identifies the unique combination of short-lived species (¹ O₂ , ∙OH, ONOO^- and O₂ ^- ) stored in hydrogels. Overall, this study demonstrates the efficacy and reveals the mechanisms of the PAH as an effective and long-term disinfectant capable of delivering and preserving antibacterial chemistries for biomedical applications.

Physicochemical Properties of Plasma-Activated Water and Its Control Effects on the Quality of Strawberries

In this study, the effects of plasma-activated water (PAW), generated by dielectric barrier discharge cold plasma at the gas–liquid interface, on the quality of fresh strawberries during storage were investigated. The results showed that, with the prolongation of plasma treatment time, the pH of PAW declined dramatically and the electrical conductivity increased significantly. The active components, including NO2−, NO3−, H2O2, and O2−, accumulated gradually in PAW, whereas the concentration of O2− decreased gradually with the treatment time after 2 min. No significant changes were found in pH, firmness, color, total soluble solids, malondialdehyde, vitamin C, or antioxidant activity in the PAW-treated strawberries (p > 0.05). Furthermore, the PAW treatment delayed the quality deterioration of strawberries and extended their shelf life. Principal component analysis and hierarchical cluster analysis showed that the PAW 2 treatment group demonstrated the best prolonged freshness effect, with the highest firmness, total soluble solids, vitamin C, and DPPH radical scavenging activity, and the lowest malondialdehyde and ∆E* values, after 4 days of storage. It was concluded that PAW showed great potential for maintaining the quality of fresh fruits and extending their shelf life.

Efficient inactivation of the contamination with pathogenic microorganisms by a combination of water spray and plasma-activated air

The global pandemic caused by SARS-CoV-2 has lasted two and a half years and the infections caused by the viral contamination are still occurring. Developing efficient disinfection technology is crucial for the current epidemic or infectious diseases caused by other pathogenic microorganisms. Gas plasma can efficiently inactivate different microorganisms, therefore, in this study, a combination of water spray and plasma-activated air was established for the disinfection of pathogenic microorganisms. The combined treatment efficiently inactivated the Omicron-pseudovirus through caused the nitration modification of the spike proteins and also the pathogenic bacteria. The combined treatment was improved with a funnel-shaped nozzle to form a temporary relatively sealed environment for the treatment of the contaminated area. The improved device could efficiently inactivate the Omicron-pseudovirus and bacteria on the surface of different materials including quartz, metal, leather, plastic, and cardboard and the particle size of the water spray did not affect the inactivation effects. This study supplied a disinfection strategy based on plasma-activated air for the inactivation of contaminated pathogenic microorganisms.

Preparation of pure active water for auto-catalytic reactions performed in it

In catalyzed electrochemical reactions, a general strategy is to modify electrode materials to increase the efficiency of the reaction. From the viewpoint of environmental protection, electrochemical reactions should be performed in an inert green water phase. In this study, we report active pure liquid water (named PV), which was collected from the condensed vapor of heated gold (Au)-containing plasmon-activated water (PAW) with a distinct structure of electron-doping and reduced hydrogen bonding (HB). The resulting PV also exhibited distinct properties of the formation of stronger intermolecular HB with alcohols, and notable activities in catalytic electrochemical reactions, compared to bulk deionized water (DIW). Moreover, the measured diffusion coefficients of water increased by ca. 30% in PV solutions. Two typical electrochemical reactions significantly increased peak currents observed in oxidation-reduction cycles (ORCs) with roughening of the Au substrate and in a model of reversible oxidation-reduction reactions on a platinum (Pt) substrate. Also, PV enhanced hydrogen evolution reactions (HERs) on catalytic Pt and inert stainless steel substrates in PV-based solutions at different pH values, compared to DIW. Moreover, these activities of PV were more marked, even better than those of PAW, when PV was collected under a higher heating rate used to heat PAW. Active pure PV has emerged as a promising green solvent applicable to various chemical reactions with more efficiency.

Physical Properties of Plasma-Activated Water

Recent observations of plasma-activated water (PAW)’s surfactant behavior suggest that the activation of water with non-equilibrium plasma can decrease the surface tension of the water. This suggested change to the surface tension also indicates that the addition of plasma can lead to changes in the physical properties of the water, knowledge of which can expand existing PAW applications and open new ones. While the chemical behavior of PAW has been extensively analyzed, to the best of our knowledge the physical properties of PAW have not been investigated. This study focuses on the need for experimental determination of PAW’s physical properties—namely, surface tension, viscosity, and contact angle. The experimental results of this study show that the addition of plasma lowers the surface tension of water at room temperature, increases the viscosity of water at high temperatures, and lowers the contact angle of droplets on glass surfaces at room temperatures. Potential factors influencing these changes include plasma alteration of the mesoscopic structure of water at low temperatures and plasma additives acting as foreign particles in water at higher temperatures. Ultimately, this investigation demonstrates that the physical properties of water change due to plasma activation, which could lead to potential industrial applications of PAW as a surfactant or as a washing-out and cleaning agent.

DNA Strand Breaks and Denaturation as Probes of Chemical Reactivity versus Thermal Effects of Atmospheric Pressure Plasma Jets

An atmospheric pressure plasma jet (APPJ) is being advanced as an alternative radiation type that offers excellent efficacy in an array of medical applications against specific biological targets such as DNA. This work explores the possibility of implementing DNA and its damage as a probe for specific plasma diagnostics such as reactive plasma species formation and transient local heating. We analyzed both APPJ characteristics based on the detection of plasma-induced strand breaks and DNA denaturation. Further, we implemented a machine learning model based on artificial neural networks to predict the type and extent of DNA damage for a given combination of APPJ parameter values. This methodology is an important step toward deciphering and explaining the potential adverse effects of APPJ on biological samples of any prospective interest in medicine.

A, Boopathy B, Chatterjee R, M. H, Chakravortty D, Rao L. Generation of neutral pH high‐strength plasma‐activated water from a pin to water discharge and its bactericidal activity on multidrug‐resistant pathogens

Plasma‐activated water (PAW) is emerging as a green alternative technology in biomedicine due to its rich and diverse aqueous reactive nitrogen and oxygen species (RONS). This study explores how to configure a pin to water (P2W) discharge to generate neutral pH high‐strength plasma‐activated water (hs‐PAW) and its bactericidal activity on hypervirulent multidrug resistance (MDR) pathogens. The factors affecting the strength of PAW, namely: water type, PAW temperature, plasma enclosure, and activation time, were studied and optimized to generate hs‐PAW having 650 ± 40 mg/l of and 215 ± 15 mg/l of H2O2 at a pH of 7. This study demonstrates a simple P2W discharge set up to handle the MDR pathogens and can be easily scalable for real‐world medical applications.

The inactivation and destruction of viruses by reactive oxygen species generated through physical and cold atmospheric plasma techniques: Current status and perspectives

BACKGROUND

Outbreaks of airborne viral infections, such as COVID-19, can cause panic regarding other severe respiratory syndrome diseases that may develop and affect public health. It is therefore necessary to develop control methods that offer protection against such viruses.

AIM OF REVIEW

To identify a feasible solution for virus deactivation, we critically reviewed methods of generating reactive oxygen species (ROS), which can attack a wide range of molecular targets to induce antiviral activity, accounting for their flexibility in facilitating host defense mechanisms against a comprehensive range of pathogens. Recently, the role of ROS in microbial decontamination has been critically investigated as a major topic in infectious diseases. ROS can eradicate pathogens directly by inducing oxidative stress or indirectly by promoting pathogen removal through numerous non-oxidative mechanisms, including autophagy, T-cell responses, and pattern recognition receptor signaling.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this article, we reviewed possible methods for the in vitro generation of ROS with antiviral activity. Furthermore, we discuss, in detail, the novel and environmentally friendly cold plasma delivery system in the destruction of viruses. This review highlights the potential of ROS as therapeutic mediators to modernize current techniques and improvement on the efficiency of inactivating SARS-CoV2 and other viruses.

Oral SARS-CoV-2 reduction by local treatment: A plasma technology application?

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.

Direct Inhibition of SARS-CoV-2 Spike Protein by Peracetic Acid

Peracetic acid (PAA) disinfectants are effective against a wide range of pathogenic microorganisms, including bacteria, fungi, and viruses. Several studies have shown the efficacy of PAA against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, its efficacy in SARS-CoV-2 variants and the molecular mechanism of action of PAA against SARS-CoV-2 have not been investigated. SARS-CoV-2 infection depends on the recognition and binding of the cell receptor angiotensin-converting enzyme 2 (ACE2) via the receptor-binding domain (RBD) of the spike protein. Here, we demonstrated that PAA effectively suppressed pseudotyped virus infection in the Wuhan type and variants, including Delta and Omicron. Similarly, PAA reduced the authentic viral load of SARS-CoV-2. Computational analysis suggested that the hydroxyl radicals produced by PAA cleave the disulfide bridges in the RBD. Additionally, the PAA treatment decreased the abundance of the Wuhan- and variant-type spike proteins. Enzyme-linked immunosorbent assay showed direct inhibition of RBD-ACE2 interactions by PAA. In conclusion, the PAA treatment suppressed SARS-CoV-2 infection, which was dependent on the inhibition of the interaction between the spike RBD and ACE2 by inducing spike protein destabilization. Our findings provide evidence of a potent disinfection strategy against SARS-CoV-2.

Enhanced Inactivation of Pseudoparticles Containing SARS-CoV-2 S Protein Using Magnetic Nanoparticles and an Alternating Magnetic Field

Severe acute respiratory syndrome coronavirus 2's (SARS-CoV-2) rapid global spread has posed a significant threat to human health, and similar outbreaks could occur in the future. Developing effective virus inactivation technologies is critical to preventing and overcoming pandemics. The infection of SARS-CoV-2 depends on the binding of the spike glycoprotein (S) receptor binding domain (RBD) to the host cellular surface receptor angiotensin-converting enzyme 2 (ACE2). If this interaction is disrupted, SARS-CoV-2 infection could be inhibited. Magnetic nanoparticle (MNP) dispersions exposed to an alternating magnetic field (AMF) possess the unique ability for magnetically mediated energy delivery (MagMED); this localized energy delivery and associated mechanical, chemical, and thermal effects are a possible technique for inactivating viruses. This study investigates the MNPs' effect on vesicular stomatitis virus pseudoparticles containing the SARS-CoV-2 S protein when exposed to AMF or a water bath (WB) with varying target steady-state temperatures (45, 50, and 55 °C) for different exposure times (5, 15, and 30 min). In comparison to WB exposures at the same temperatures, AMF exposures resulted in significantly greater inactivation in multiple cases. This is likely due to AMF-induced localized heating and rotation of MNPs. In brief, our findings demonstrate a potential strategy for combating the SARS-CoV-2 pandemic or future ones.

Polyimide Surface Dielectric Barrier Discharge for Inactivation of SARS-CoV-2 Trapped in a Polypropylene Melt-Blown Filter

Surface dielectric barrier discharge (SDBD) was used to inactivate the infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) trapped in a polypropylene (PP) melt-blown filter. We used a dielectric barrier made of polyimide films with hexagonal holes through which air flowed. In a cylindrical wind tunnel, the SDBD device supplied reactive oxygen species such as ozone to the SARS-CoV-2 trapped in the PP filter. A plaque assay showed that SDBD at an ozone concentration of approximately 51.6 ppm and exposure time of 30 min induced more than 99.78% reduction for filter-adhered SARS-CoV-2. A carbon catalyst after SDBD effectively reduced ozone exhaust below 0.05 ppm. The combination of SDBD, PP filter, and catalyst could be a promising way to decrease the risk of secondary infection due to indoor air purifiers.

Effects of non-thermal atmospheric plasma on protein

Currently, the advancement in non-thermal atmospheric plasma technology enables plasma treatments on some heat-sensitive targets, including biological substances, without unspecific damage caused by thermal effect. The significant effects of non-thermal atmospheric plasma modulating biological events have been demonstrated by considerable studies. Protein, one of the most important biomolecules, participates in the majority of the life-sustaining activities in all organisms, whose functions are derived from the diverse biochemical properties of amino acid compositions and four-tiered protein structure hierarchy. Therefore, the knowledge of how non-thermal atmospheric plasma affects protein greatly benefits the understanding and application of the non-thermal atmospheric plasma's effect in biological area. In this review, we summarize recent research progress on the effects of non-thermal atmospheric plasma, particularly its reactive species, on biochemical and biophysical characteristics of proteins at different structural levels that leads to their functional changes. Moreover, the physiological effects of non-thermal atmospheric plasma at cellular or organism level driven by the manipulations on protein and their relative application prospects are reviewed. Despite the exceptional application potential, the exploration of the non-thermal atmospheric plasma's effect on protein still confronts with difficulties due to the limited knowledge of the underlying mechanisms and the complexity of non-thermal atmospheric plasma operation systems, which requires further studies and standardization of non-thermal atmospheric plasma treatments.

Revealing low-temperature plasma efficacy through a dose-rate assessment by DNA damage detection combined with machine learning models

Low-temperature plasmas have quickly emerged as alternative and unconventional types of radiation that offer great promise for various clinical modalities. As with other types of radiation, the therapeutic efficacy and safety of low-temperature plasmas are ubiquitous concerns, and assessing their dose rates is crucial in clinical settings. Unfortunately, assessing the dose rates by standard dosimetric techniques has been challenging. To overcome this difficulty, we proposed a dose-rate assessment framework that combined the predictive modeling of plasma-induced damage in DNA by machine learning with existing radiation dose-DNA damage correlations. Our results indicated that low-temperature plasmas have a remarkably high dose rate that can be tuned by various process parameters. This attribute is beneficial for inducing radiobiological effects in a more controllable manner.

Emerging nanobiotechnology for precise theranostics of hepatocellular carcinoma

Primary liver cancer has become the second most fatal cancer in the world, and its five-year survival rate is only 10%. Most patients are in the middle and advanced stages at the time of diagnosis, losing the opportunity for radical treatment. Liver cancer is not sensitive to chemotherapy or radiotherapy. At present, conventional molecularly targeted drugs for liver cancer show some problems, such as short residence time, poor drug enrichment, and drug resistance. Therefore, developing new diagnosis and treatment methods to effectively improve the diagnosis, treatment, and long-term prognosis of liver cancer is urgent. As an emerging discipline, nanobiotechnology, based on safe, stable, and efficient nanomaterials, constructs highly targeted nanocarriers according to the unique characteristics of tumors and further derives a variety of efficient diagnosis and treatment methods based on this transport system, providing a new method for the accurate diagnosis and treatment of liver cancer. This paper aims to summarize the latest progress in this field according to existing research and the latest clinical diagnosis and treatment guidelines in hepatocellular carcinoma (HCC), as well as clarify the role, application limitations, and prospects of research on nanomaterials and the development and application of nanotechnology in the diagnosis and treatment of HCC.

Cold atmospheric plasma for addressing the COVID-19 pandemic

The coronavirus disease 2019 (COVID-19) pandemic has greatly stressed the global community, exposing vulnerabilities in the supply chains for disinfection materials, personal protective equipment, and medical resources worldwide. Disinfection methods based on cold atmospheric plasma (CAP) technologies offer an intriguing solution to many of these challenges because they are easily deployable and do not require resource-constrained consumables or reagents needed for conventional decontamination practices. CAP technologies have shown great promise for a wide range of medical applications from wound healing and cancer treatment to sterilization methods to mitigate airborne and fomite transfer of viruses. This review engages the broader community of scientists and engineers that wish to help the medical community with the ongoing COVID-19 pandemic by establishing methods to utilize broadly applicable CAP technologies.

Regulating the Electronic Configuration of Spinel Zinc Manganate Derived from Metal-Organic Frameworks: Controlled Synthesis and Application in Anode Materials for Lithium-Ion Batteries

In recent years, transition metal oxides have been considered as the most promising anode materials due to their high theoretical capacity, low price, and abundant natural reserves. Among them, zinc manganate is used as an electrode material for anodes, whose application is mostly hindered due to its poor ionic/electronic conductivity. In this work, a series of ZnMn₂O₄ (ZMO) are synthesized by a hydrothermal technique coordinated with a metal-organic framework-based high-temperature calcination process for their application as an anode in lithium-ion batteries (LIBs). Meanwhile, this study systematically explores the influence of carbon doping and the types of organic ligands and oxygen vacancies on the electrochemical properties of the synthesized ZMO. Density functional theory (DFT) calculations and experimental investigations reveal that the introduction of carbon and oxygen vacancies can enhance electronic conductivity, more active sites and faster Li⁺ adsorption, resulting in better electrochemical performances. As expected, all ZMOs with carbon doping (PMA-ZMO, MI-ZMO, and BDC-ZMO) derived from 1,2,4,5-benzenetetracarboxylic acid, 2-methylimidazole, and 1,4-dicarboxybenzene achieve outstanding electrochemical performance. Meanwhile, the introduction of oxygen vacancies can enhance the electronic conductivity and can significantly reduce the activation energy of Li⁺ transport, thereby accelerating the Li⁺ diffusion kinetics in the lithiation/delithiation process. Furthermore, an optimal ZMO anode material synthesized by 2-methylimidazole delivers a high reversible capacity of 1174.7 mA h g^-1 after 300 cycles at 0.1 A g^-1 and 600 mA h g^-1 at 0.5 A g^-1 after 300 cycles. After high-rate charge and discharge cycles, the specific capacity rapidly recovers to a value greater than the initial value, which proves the unusual activation and thereby an excellent rate property of the electrode. Hence, we conclude that ZMO provides potential application prospects as an anode electrode material for LIBs.

Disinfection of corona and myriad viruses in water by non-thermal plasma: a review

Nowadays, in parallel to the appearance of the COVID-19 virus, the risk of viruses in water increases leading to the necessity of developing novel disinfection methods. This review focuses on the route of virus contamination in water and introduces non-thermal plasma technology as a promising method for the inactivation of viruses. Effects of essential parameters affecting the non-thermal discharge for viral inactivation have been exposed. The review has also illustrated a critical discussion of this technology with other advanced oxidation processes. Additionally, the inactivation mechanisms have also been detailed based on reactive oxygen and nitrogen species.

Hierarchical Sulfide-Rich Modification Layer on SiO/C Anode for Low-Temperature Li-Ion Batteries

The silicon oxide/graphite (SiO/C) composite anode represents one of the promising candidates for next generation Li-ion batteries over 400 Wh kg-1 . However, the rapid capacity decay and potential safety risks at low temperature restrict their widely practical applications. Herein, the fabrication of sulfide-rich solid electrolyte interface (SEI) layer on surface of SiO/C anode to boost the reversible Li-storage performance at low temperature is reported. Different from the traditional SEI layer, the present modification layer is composed of inorganic-organic hybrid components with three continuous layers as disclosed by time-of-flight secondary ion mass spectrometry (TOF-SIMS). The result shows that ROSO2 Li, ROCO2 Li, and LiF uniformly distribute over different layers. When coupled with LiNi0.8 Co0.1 Mn0.1 O2 cathode, the capacity retention achieves 73% at -20 °C. The first principle calculations demonstrate that the gradient adsorption of sulfide-rich surface layer and traditional intermediate layer can promote the desolvation of Li+ at low temperature. Meanwhile, the inner LiF-rich layer with rapid ionic diffusion capability can inhibit dendrite growth. These results offer new perspective of developing advanced SiO/C anode and low-temperature Li-ion batteries.

A Cold Plasma Technology for Ensuring the Microbiological Safety and Quality of Foods

Changing consumers’ taste for chemical and thermally processed food and preference for perceived healthier minimally processed alternatives is a challenge to food industry. At present, several technologies have found usefulness as choice methods for ensuring that processed food remains unaltered while guaranteeing maximum safety and protection of consumers. However, the effectiveness of most green technology is limited due to the formation of resistant spores by certain foodborne microorganisms and the production of toxins. Cold plasma, a recent technology, has shown commendable superiority at both spore inactivation and enzymes and toxin deactivation. However, the exact mechanism behind the efficiency of cold plasma has remained unclear. In order to further optimize and apply cold plasma treatment in food processing, it is crucial to understand these mechanisms and possible factors that might limit or enhance their effectiveness and outcomes. As a novel non-thermal technology, cold plasma has emerged as a means to ensure the microbiological safety of food. Furthermore, this review presents the different design configurations for cold plasma applications, analysis the mechanisms of microbial spore and biofilm inactivation, and examines the impact of cold plasma on food compositional, organoleptic, and nutritional quality.

Novel strategies towards efficient molecular biohydrogen production by dark fermentative mechanism: present progress and future perspective

In the scenario of alarming increase in greenhouse and toxic gas emissions from the burning of conventional fuels, it is high time that the population drifts towards alternative fuel usage to obviate pollution. Hydrogen is an environment-friendly biofuel with high energy content. Several production methods exist to produce hydrogen, but the least energy intensive processes are the fermentative biohydrogen techniques. Dark fermentative biohydrogen production (DFBHP) is a value-added, less energy-consuming process to generate biohydrogen. In this process, biohydrogen can be produced from sugars as well as complex substrates that are generally considered as organic waste. Yet, the process is constrained by many factors such as low hydrogen yield, incomplete conversion of substrates, accumulation of volatile fatty acids which lead to the drop of the system pH resulting in hindered growth and hydrogen production by the bacteria. To circumvent these drawbacks, researchers have come up with several strategies that improve the yield of DFBHP process. These strategies can be classified as preliminary methodologies concerned with the process optimization and the latter that deals with pretreatment of substrate and seed sludge, bioaugmentation, co-culture of bacteria, supplementation of additives, bioreactor design considerations, metabolic engineering, nanotechnology, immobilization of bacteria, etc. This review sums up some of the improvement techniques that profoundly enhance the biohydrogen productivity in a DFBHP process.

Non-Thermal Plasma Jet-Treated Medium Induces Selective Cytotoxicity against Mycobacterium tuberculosis-Infected Macrophages

Plasma-treated media (PTM) serve as an adjuvant therapy to postoperatively remove residual cancerous lesions. We speculated that PTM could selectively kill cells infected with Mycobacterium tuberculosis (Mtb) and remove postoperative residual tuberculous lesions. We therefore investigated the effects of a medium exposed to a non-thermal plasma jet on the suppression of intracellular Mtb replication, cell death, signaling, and selectivity. We propose that PTM elevates the levels of the detoxifying enzymes, glutathione peroxidase, catalase, and ataxia-telangiectasia mutated serine/threonine kinase and increases intracellular reactive oxygen species production in Mtb-infected cells. The bacterial load was significantly decreased in spleen and lung tissues and single-cell suspensions from mice intraperitoneally injected with PTM compared with saline and untreated medium. Therefore, PTM has the potential as a novel treatment that can eliminate residual Mtb-infected cells after infected tissues are surgically resected.

Cold Atmospheric Plasma Ameliorates Skin Diseases Involving Reactive Oxygen/Nitrogen Species-Mediated Functions

Skin diseases are mainly divided into infectious diseases, non-infectious inflammatory diseases, cancers, and wounds. The pathogenesis might include microbial infections, autoimmune responses, aberrant cellular proliferation or differentiation, and the overproduction of inflammatory factors. The traditional therapies for skin diseases, such as oral or topical drugs, have still been unsatisfactory, partly due to systematic side effects and reappearance. Cold atmospheric plasma (CAP), as an innovative and non-invasive therapeutic approach, has demonstrated its safe and effective functions in dermatology. With its generation of reactive oxygen species and reactive nitrogen species, CAP exhibits significant efficacies in inhibiting bacterial, viral, and fungal infections, facilitating wound healing, restraining the proliferation of cancers, and ameliorating psoriatic or vitiligous lesions. This review summarizes recent advances in CAP therapies for various skin diseases and implicates future strategies for increasing effectiveness or broadening clinical indications.

Recent developments in the use of cold plasma, high hydrostatic pressure, and pulsed electric fields on microorganisms and viruses in seafood

Non-thermal processing methods, such as cold plasma (CP), high pressure processing (HPP) and pulsed electric fields (PEF), have been proposed for natural and fresh-like foods to inactivate microorganisms at nearly-ambient or moderate temperature. Since natural, safe, and healthy foods with longer shelf-life are increasingly demanded, these requests are challenging to fulfill by using current thermal processing technologies. Thus, novel preservation technologies based on non-thermal processing methods are required. The aim of this article is to provide recent developments in maintaining seafood safety via CP, HHP, and PEF technologies, as well as their mechanisms of action regarding contamination with food-borne microorganisms. Their application to control parasites, spores and the possibility to eradicate the hazard of SARS-CoV-2 transmission through seafood products are also discussed. CP, HHP, and PEF have been applied to inactivate food-borne microorganisms in the seafood industry. However, the drawbacks for each emerging technology have also been reported. To ensure safety and maintain quality of seafood products, the combination of these processing techniques with natural antimicrobial agents or existing thermal methods may be more applicable in the case of the seafood industry. Further studies are required to examine the effects of these methods on viruses, parasites, and SARS-CoV-2 in seafood.

Efficient disinfection of SARS-CoV-2-like coronavirus, pseudotyped SARS-CoV-2 and other coronaviruses using cold plasma induces spike protein damage

Coronavirus disease 2019 (COVID-19) has become a worldwide public health emergency, and the high transmission of SARS-CoV-2 variants has raised serious concerns. Efficient disinfection methods are crucial for the prevention of viral transmission. Herein, pulse power-driven cold atmospheric plasma (CAP), a novel sterilization strategy, was found to potently inactivate SARS-CoV-2-like coronavirus GX_P2V, six strains of major epidemic SARS-CoV-2 variants and even swine coronavirus PEDV and SADS-CoV within 300 s (with inhibition rate more than 99%). We identified four dominant short-lived reactive species, ONOO^-, ¹O₂, O₂^- and·OH, generated in response to CAP and distinguished their roles in the inactivation of GX_P2V and SARS-CoV-2 spike protein receptor binding domain (RBD), which is responsible for recognition and binding to human angiotensin-converting enzyme 2 (hACE2). Our study provides detailed evidence of a novel surface disinfection strategy for SARS-CoV-2 and other coronaviruses.

Antimicrobial effects of microwave plasma-activated water with skin protective effect for novel disinfectants in pandemic era

Skin antiseptics have important implications for public health and medicine. Although conventional antiseptics have considerable antimicrobial activity, skin toxicity and the development of resistance are common problems. Plasma-treated water has sterilization and tissue-regenerative effects. Therefore, the aim of this study was to identify whether plasma-activated water (PAW) manufactured by our microwave plasma system can be used as a novel antiseptic solution for skin protection. PAW was produced by dissolving reactive nitrogen oxide gas using microwave plasma in deionized water. The antibacterial effects of PAW against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Salmonella typhimurium and effective concentrations were investigated by a solid agar plate assay. The factors mediating the effects of PAW were evaluated by the addition of reactive species scavengers. Cytotoxicity and cell viability assays were performed to examine the protective effect of PAW on normal skin cells. PAW exhibited excellent sterilization and no toxicity in normal skin cells. Experiments also confirmed the potential of PAW as a sanitizer for SARS-CoV-2. Our findings support the use of PAW as an effective skin disinfectant with good safety in the current situation of a global pandemic.

Cold atmospheric pressure plasma for attenuation of SARS-CoV-2 spike protein binding to ACE2 protein and the RNA deactivation

Cold atmospheric pressure (CAP) plasma has a profound effect on protein-protein interactions. In this work, we have highlighted the deactivation of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike protein by CAP plasma treatment. Complete deactivation of spike protein binding to the human ACE2 protein was observed within an exposure time of 5 minutes which is correlated to the higher concentration of hydrogen peroxide formation due to the interaction with the reactive oxygen species present in the plasma. On the other hand, we have established that CAP plasma is also capable of degrading RNA of SARS-CoV-2 virus which is also linked to hydrogen peroxide concentration. The reactive oxygen species is produced in the plasma by using noble gases such as helium, in the absence of any other chemicals. Therefore, it is a green process with no chemical waste generated and highly advantageous from the environmental safety prospects. Results of this work could be useful in designing plasma-based disinfection systems over those based on environmentally hazardous chemical-based disinfection and biomedical applications.

Cold atmospheric plasma for preventing infection of viruses that use ACE2 for entry

Rational: The mutating SARS-CoV-2 potentially impairs the efficacy of current vaccines or antibody-based treatments. Broad-spectrum and rapid anti-virus methods feasible for regular epidemic prevention against COVID-19 or alike are urgently called for. Methods: Using SARS-CoV-2 virus and bioengineered pseudoviruses carrying ACE2-binding spike protein domains, we examined the efficacy of cold atmospheric plasma (CAP) on virus entry prevention. Results: We found that CAP could effectively inhibit the entry of virus into cells. Direct CAP or CAP-activated medium (PAM) triggered rapid internalization and nuclear translocation of the virus receptor, ACE2, which began to return after 5 hours and was fully recovered by 12 hours. This was seen in vitro with both VERO-E6 cells and human mammary epithelial MCF10A cells, and in vivo. Hydroxyl radical (·OH) and species derived from its interactions with other species were found to be the most effective CAP components for triggering ACE2 nucleus translocation. The ERα/STAT3(Tyr705) and EGFR(Tyr1068/1086)/STAT3(Tyr705) axes were found to interact and collectively mediate the effects on ACE2 localization and expression. Conclusions: Our data support the use of PAM in helping control SARS-CoV-2 if developed into products for nose/mouth spray; an approach extendable to other viruses utilizing ACE2 for host entry.

Plasma bioscience for medicine, agriculture and hygiene applications

Nonthermal biocompatible plasma (NBP) sources operating in atmospheric pressure environments and their characteristics can be used for plasma bioscience, medicine, and hygiene applications, especially for COVID-19 and citizen. This review surveyed the various NBP sources, including a plasma jet, micro-DBD (dielectric barrier discharge) and nanosecond discharged plasma. The electron temperatures and the plasma densities, which are produced using dielectric barrier discharged electrode systems, can be characterized as 0.7 ~ 1.8 eV and (3-5) × 1014-15 cm-3, respectively. Herein, we introduce a general schematic view of the plasma ultraviolet photolysis of water molecules for reactive oxygen and nitrogen species (RONS) generation inside biological cells or living tissues, which would be synergistically important with RONS diffusive propagation into cells or tissues. Of the RONS, the hydroxyl radical [OH] and hydrogen peroxide H2O2 species would mainly result in apoptotic cell death with other RONS in plasma bioscience and medicines. The diseased biological protein, cancer, and mutated cells could be treated by using a NBP or plasma activated water (PAW) resulting in their apoptosis for a new paradigm of plasma medicine.

Degradation of contaminants in plasma technology: An overview

The information of plasma technologies applications for environmental clean-up on treating and degrading metals, metalloids, dyes, biomass, antibiotics, pesticides, volatile organic compounds (VOCs), bacteria, virus and fungi is compiled and organized in the review article. Different reactor configurations of plasma technology have been applied for reactive species generation, responsible for the pollutants removal, hydrogen and methane production and microorganism inactivation. Therefore, in this review article, the reactive species from discharge plasma are presented here to provide the insight into the environmental applications. The combinations of plasma technology with flux agent and photocatalytic are also given in this review paper associated with the setup of the plasma system on the removal process of metals, VOCs, and microorganisms. Furthermore, the potential of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivation via plasma technology is also described in this review paper. Detailed information of plasma parameter configuration is given to support the influence of the critical process in the plasma system to deal with contaminants.

Evaluation of Betacoronavirus OC43 and SARS-CoV-2 Elimination by Zefero Air Sanitizer Device in a Novel Laboratory Recirculation System

Indoor air sanitizers contrast airborne diseases and particularly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/Coronavirus disease 2019 (COVID-19). The commercial air sanitizer Zefero (Cf7 S.r.l., San Giovanni La Punta, Italy) works alternatively using a set of integrated disinfecting technologies (namely Photocatalysis/UV mode) or by generating ozone (Ozone mode). Here we evaluated the virucidal efficacy of Zefero setup modes against human Betacoronavirus OC43 and SARS-CoV-2. For this purpose, we designed a laboratory test system in which each virus, as aerosol, was treated with Photocatalysis/UV or Ozone mode and returned into a recirculation plexiglass chamber. Aerosol samples were collected after different times of exposure, corresponding to different volumes of air treated. The viral RNA concentration was determined by qRT-PCR. In Photocatalysis/UV mode, viral RNA of OC43 or SARS-CoV-2 was not detected after 120 or 90 min treatment, respectively, whereas in Ozone mode, viruses were eliminated after 30 or 45 min, respectively. Our results indicated that the integrated technologies used in the air sanitizer Zefero are effective in eliminating both viruses. As a reliable experimental system, the recirculation chamber developed in this study represents a suitable apparatus for effectively comparing the disinfection capacity of different air sanitizers.

Visual naked-eye detection of SARS-CoV-2 RNA based on covalent organic framework capsules

The ongoing outbreak of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted that new diagnosis technologies are crucial for controlling the spread of the disease. Especially in the resources-limit region, conveniently operated detection methods such as "naked-eye" detection are urgently required that no instrument is needed. Herein, we have designed a novel and facile strategy to fabricate covalent organic framework (COF) capsules, which can be utilized to establish a new colorimetric assay for naked-eye detection of SARS-CoV-2 RNA. Specifically, we employ the digestible ZIF-90 as the sacrificial template to prepare the hollow COF capsules for horseradish peroxidase (HRP) encapsulation. The fabricated COF capsules can provide an appropriate microenvironment for the enzyme molecules, which may improve the conformational freedom of enzymes, enhance the mass transfer, and endow the enzyme with high environmental resistance. With such design, the proposed assay exhibits outstanding analytical performance for the detection of SARS-CoV-2 RNA in the linear range from 5 pM to 50 nM with a detection limit of 0.28 pM which can go parallel to qTR-PCR analysis. Our method also possesses excellent selectivity and reproducibility. Moreover, this method can also be served to analyze the clinical samples, and can successfully differentiate COVID-19 patients from healthy people, suggesting the promising potential in clinical diagnosis.