Analysis of reactive oxygen and nitrogen species generated in three liquid media by low temperature helium plasma jet

Progress and limitations in reactive oxygen species quantitation

Reactive oxygen species (ROS) are a set of oxygen- and nitrogen-containing radicals. They are produced from a wide range of sources. In biological contexts, cellular stress leads to an overproduction of ROS, which can lead to genetic damage and disease development. In industry, ROS are often productively used for water purification or for analyzing the possible toxicity of an industrial process. Because of their ubiquity, detection of ROS has been an analytical goal across a range of fields. To understand complicated systems and origins of ROS production, it is necessary to move from qualitative detection to quantitation. Analytical techniques that combine quantitation, high spatial and temporal resolution, and good specificity represent detection methods that can fill critical gaps in ROS research. Herein, we discuss the continued progress and limitations of fluorescence, electrochemical, and electron paramagnetic resonance detection of ROS over the last ten years, giving suggestions for the future of the field.

Reactive oxygen species from non-thermal gas plasma (CAP): implication for targeting cancer stem cells

Cancer remains a major global health challenge, with the persistence of cancer stem cells (CSCs) contributing to treatment resistance and relapse. Despite advancements in cancer therapy, targeting CSCs presents a significant hurdle. Non-thermal gas plasma, also known as CAP, represents an innovative cancer treatment. It has recently gained attention for its often found to be selective, immunogenic, and potent anti-cancer properties. CAP is composed of a collection of transient, high-energy, and physically and chemically active entities, such as reactive oxygen species (ROS). It is acknowledged that the latter are responsible for a major portion of biomedical CAP effects. The dynamic interplay of CAP-derived ROS and other components contributes to the unique and versatile properties of CAP, enabling it to interact with biological systems and elicit various therapeutic effects, including its potential in cancer treatment. While CAP has shown promise in various cancer types, its application against CSCs is relatively unexplored. This review assesses the potential of CAP as a therapeutic strategy for targeting CSCs, focusing on its ability to regulate cellular states and achieve redox homeostasis. This is done by providing an overview of CSC characteristics and demonstrating recent findings on CAP's efficacy in targeting these cells. By contributing insights into the unique attributes of CSCs and the potential of CAP, this work contributes to an advanced understanding of innovative oncology strategies.

The impact of plasma-activated water on the process of nickel bioremediation by Neowestiellopsis persica A1387

Cyanobacteria provide an economical, feasible, and environmentally friendly solution for heavy metal removal. In addition, plasma can facilitate the removal of heavy metals across various time frames. In this study, we applied plasma-activated water (PAW) to prepare Neowestiellopsis persica A1387 strain medium culture for 0, 10, 15, and 20 min via an Atmospheric Cold Plasma Jet device (ACPJ-17A). Nickel removal efficiency was evaluated after 48 hours of cultivation under controlled conditions at 0, 10, 30, 60, and 90 min. Further investigation was performed through FTIR, GC-MS, and XRD techniques. Statistical analysis of ANOVA and Tukey's test indicated that the samples treated for 15 min had the highest biomass dry weight, polysaccharide content, and nickel removal rate (p ≤ 0.05). The GC-MS analysis presented elevated concentrations of ethanol, 1,3-dimethylbenzene, acetic acid, 3-methylbutyl ester, aromatic chemicals, 2-methyl-1-propanol, and 3-octen-2-ol in all samples treated with plasma. The functional group analysis using the FT-IR approach showed increased peak intensities with more extended treatment periods, indicating the addition of methyl, methylene, and hydroxyl groups to the cyanobacterium cell wall. Furthermore, a peak at 468 cm⁻¹ wavelength was observed, correlating to the Ni-O stretching mode after absorption of Ni on the cyanobacterium surface. The XRD data exhibited prominent peaks in all diffraction patterns angles below 20 degrees, suggesting the presence of amorphous and non-crystalline chemical structures within the cyanobacterial structures. The peak intensity increased with longer treatment durations. The 15-min plasma treatment optimized Ni removal, but the efficiency decreased with prolonged exposure due to adverse effects such as increased reactive oxygen species (ROS) production.

Microscopic mechanistic study of the penetration distributions for plasma reactive oxygen and nitrogen species based on sialic acid targeting on the cell membrane surface

The ability of cold atmospheric plasmas (CAPs) to produce a wide range of active constituents while maintaining a low or even room temperature of the gas has made it a novel research area of great interest. During plasma action, cancer cell membrane surface components are susceptible to oxidative modification by reactive oxygen and nitrogen species (RONS). In this study, the process of oxidative modification of membrane surface components sialic acid by RONS was investigated based on molecular dynamics simulations, and the penetration mechanism of long-lived particles ONOOH and its homolytic products at the membrane-water interface and the effect of appropriate electric field action were studied. The results showed that cancer cells with high sialic acid expression were less stable than healthy cells. Plasma treatment may promote the ONOOH homolysis process, and its homolysis product OH free radical is more likely to adsorb near sialic acid molecules by hydrogen bonding, resulting in oxidative modification. The interaction force between OH free radical and sialic acid molecules is stronger than ONOOH, which helps to further understand the oxidative modification reaction in membrane environment. At the same time, appropriate electric field stimulation can enhance the depth of penetration of RONS to more effectively treat the pathological state of biological tissues. The study proposes the use of membrane surface sialic acid as a cancer therapeutic target and provides guidance for improving the depth of RONS penetration and maximizing the survival of healthy cells, which contributes to the further clinical translation of plasma biomedicine.

Determining the Effect of Non-Thermal Plasma on the Transmembrane Kinetics of Melittin through Molecular Explorations

Non-thermal plasma (NTP) synergistic anticancer strategies are a current hotspot of interest at the intersection of plasma biomedicine. Melittin (MEL) has been shown to inhibit cancer in many malignant tumors; however, its clinical application is controversial. Therefore, the transmembrane process and mechanism of MEL activity in different cell systems were studied and the combination of MEL and NTP was proposed in this paper. The results showed that the electrostatic attraction between MEL and the lipid bilayer contributes to the stable orientation of MEL on the membrane surface. In addition, sialic acid overexpression affects the degree to which MEL binds the membrane system and the stability of the membrane structure. The use of NTP to reduce the dosage of MEL and its related nonspecific cytolysis activity has certain clinical application value. The results of this study provide theoretical support for improving the clinical applicability of MEL and contribute to the further development of plasma biomedicine.

Efficient degradation of F-53B as PFOS alternative in water by plasma discharge: Feasibility and mechanism insights

The frequent detection of 6:2 chlorinated polyfluorinated ether sulfonate (F-53B) in various environments has raised concerns owing to its comparable or even higher environmental persistence and toxicity than perfluorooctane sulfonate (PFOS). This study investigated the plasma degradation of F-53B for the first time using a water film plasma discharge system. The results revealed that F-53B demonstrated a higher rate constant but similar defluorination compared to PFOS, which could be ascribed to the introduction of the chlorine atom. Successful elimination (94.8-100 %) was attained at F-53B initial concentrations between 0.5 and 10 mg/L, with energy yields varying from 15.1 to 84.5 mg/kWh. The mechanistic exploration suggested that the decomposition of F-53B mainly occurred at the gas-liquid interface, where it directly reacted with reactive species generated by gas discharge. F-53B degradation pathways involving dechlorination, desulfonation, carboxylation, C-O bond cleavage, and stepwise CF2 elimination were proposed based on the identified byproducts and theoretical calculations. Furthermore, the demonstrated effectiveness in removing F-53B in various coexisting ions and water matrices highlighted the robust anti-interference ability of the treatment process. These findings provide mechanistic insights into the plasma degradation of F-53B, showcasing the potential of plasma processes for eliminating PFAS alternatives in water.

Cold atmospheric plasma-activated medium for potential ovarian cancer therapy

Cold atmospheric plasma (CAP) has emerged as an innovative tool with broad medical applications, including ovarian cancer (OC) treatment. By bringing CAP in close proximity to liquids such as water or cell culture media, solutions containing reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated, called plasma-activated media (PAM). In this systematic review, we conduct an in-depth analysis of studies focusing on PAM interactions with biological substrates. We elucidate the diverse mechanisms involved in the activation of different media and the complex network of chemical reactions underlying the generation and consumption of the prominent reactive species. Furthermore, we highlight the promises of PAM in advancing biomedical applications, such as its stability for extended periods under appropriate storage conditions. We also examine the application of PAM as an anti-cancer and anti-metastatic treatment for OC, with a particular emphasis on its ability to induce apoptosis via distinct signaling pathways, inhibit cell growth, suppress cell motility, and enhance the therapeutic effects of chemotherapy. Finally, the future outlook of PAM therapy in biomedical applications is speculated, with emphasis on the safety issues relevant to clinical translation.

Evidence for Superoxide-Initiated Oxidation of Aniline in Water by Pulsed, Atmospheric Pressure Plasma

Plasma-driven solution electrochemistry (PDSE) uses plasma-generated reactive species to drive redox reactions in solution. Nonthermal, atmospheric pressure plasmas, when irradiating water, produce many redox species. While PDSE is a promising chemical tool, there is limited insight into the mechanisms of the reactions due to the variety of short-lived reagents produced. In this study, we use aniline as a model system for studying redox mechanisms of PDSE. We show that the plasma irradiation of aqueous aniline solutions drives the formation of polyaniline oligomer, which is suppressed under acidic starting conditions. The addition of (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO), a radical scavenger, decreases the formation of oligomer by 80%, and the addition of superoxide dismutase fully hinders oligomerization. These results lead us to conclude that the oligomerization of aniline by plasma irradiation is initiated by superoxide. This discovery provides novel insights into PDSE mechanisms and illustrates a potential method of harnessing superoxide for chemical reactions.

Characteristics of Aqueous Chemical Species Generation in Plasma-Facing Liquid Systems Using Helium Jet Plasma

Plasma-facing liquids (PFLs) facilitate the storage of reactive O and N species (RONS), including H2O2 and NO2 -, which remain in the PFL after plasma treatment, and they can continuously influence the target immersed in the liquid. However, their behaviors and levels of generation and extinction depend strongly on the plasma characteristics and liquid condition. Therefore, understanding the effects of the liquid type on the plasma discharge characteristics and the RONS generated via plasma discharge is necessary. We compared the RONS generation and storage trends of deionized H2O and a high-conductivity PFL, RPMI 1640, which is a well-known cell culture medium commonly used to culture mammalian cells. RPMI 1640 acted as an electrode and enhanced the plasma discharge power by supplying abundant radicals and RONS. The production of gaseous hydroxyl radicals and NO markedly increased, which facilitated H2O2 and NO2 - production in the PFL for the first 200 s, and then the increase in the RONS concentration stagnated. With respect to storage, as the components within RMPI 1640 exhibited high reaction constants for their reactions with H2O2, H2O2 elimination was completed in <30 min. Unlike H2O2, the concentration of NO2 - in the PFL was unchanged.

Nitric oxide-dependent cell death in glioblastoma and squamous cell carcinoma via prodeath mitochondrial clustering

Besides the fission-fusion dynamics, the cellular distribution of mitochondria has recently emerged as a critical biological parameter in regulating mitochondrial function and cell survival. We previously found that mitochondrial clustering on the nuclear periphery, or monopolar perinuclear mitochondrial clustering (MPMC), accompanies the anticancer activity of air plasma-activated medium (APAM) against glioblastoma and human squamous cell carcinoma, which is closely associated with oxidant-dependent tubulin remodeling and mitochondrial fragmentation. Accordingly, this study investigated the regulatory roles of nitric oxide (NO) in the anticancer activity of APAM. Time-lapse analysis revealed a time-dependent increase in NO accompanied by MPMC. In contrast, APAM caused minimal increases in MPMC and NO levels in nontransformed cells. NO, hydroxyl radicals, and lipid peroxide levels increased near the damaged nuclear periphery, possibly within mitochondria. NO scavenging prevented tubulin remodeling, MPMC, perinuclear oxidant production, nuclear damage, and cell death. Conversely, synthetic NO donors augmented all the prodeath events and acted synergistically with APAM. Salinomycin, an emerging drug against multidrug-resistant cancers, had similar NO-dependent effects. These results suggest that APAM and salinomycin induce NO-dependent cell death, where MPMC and oxidative mitochondria play critical roles. Our findings encourage further investigations on MPMC as a potential target for NO-driven anticancer agents against drug-resistant cancers.

Assessing the Effects of Cold Atmospheric Plasma on the Natural Microbiota and Quality of Pork during Storage

Cold atmospheric plasma (CAP) is a novel non-thermal technology with significant potential for use in meat processing to prolong shelf life. The objective of the study was to evaluate the efficiency of CAP treatment on the natural microbiota and quality traits of pork stored for 8 days at 4 °C. CAP treatment was applied by employing piezoelectric direct discharge technology to treat pork samples for 0, 3, 6, and 9 min. Reductions of approximately 0.8-1.7 log CFU/g were observed in total viable counts (TVC) and Pseudomonas spp. levels for CAP treatments longer than 3 min, immediately after treatment. A storage study revealed that CAP-treated pork (>6 min) had significantly lower levels of TVC, Pseudomonas spp., and Enterobacteriaceae throughout storage. Regarding quality traits, CAP application for longer than 3 min significantly increased water retention and yellowness and decreased meat redness compared to untreated pork. However, other parameters such as pH, tenderness, and lightness exhibited no statistically significant differences between untreated and CAP-treated pork. Lipid oxidation levels were higher only for the 9-min treatment compared to untreated pork. Our results revealed that CAP is a promising technology that can extend the microbiological shelf life of pork during refrigeration storage.

In-package cold plasma treatment to extend the shelf life of food

Conventional food preservation methods such as heat treatment, irradiation, chemical treatment, refrigeration, and coating have various disadvantages, like loss of food quality, nutrition, and cost-effectiveness. Accordingly, cold plasma is one of the new technologies for food processing and has played an important role in preventing food spoilage. Specifically, in-package cold plasma has become a modern trend to decontaminate, process, and package food simultaneously. This strategy has proven successful in processing various fresh food ingredients, including spinach, fruits, vegetables, and meat. In particular, cold plasma treatment within the package reduces the risk of post-processing contamination. Cryoplasm decontamination within packaging has been reported to reduce significantly the microbial load of many foods' spoilage-causing pathogens. However, studies are needed to focus more on the effects of in-package treatments on endogenous enzyme activity, pest control, and removal of toxic pesticide residues. In this review, we comprehensively evaluated the efficacy of in-package low-temperature plasma treatment to extend the shelf life of various foods. The mechanisms by which cold plasma interacts with food were investigated, emphasizing its effects on pathogen reduction, spoilage mitigation, and surface modification. The review also critically assessed the effects of the treatments on food quality, regulatory considerations, and their potential as viable technologies to improve food safety and packaging life. In-package cold plasma treatment could revolutionize food storage when combined with other sophisticated technologies such as nanotechnology.

Epidermal growth factor potentiates EGFR(Y992/1173)-mediated therapeutic response of triple negative breast cancer cells to cold atmospheric plasma-activated medium

Cold atmospheric plasma (CAP) holds promise as a cancer-specific treatment that selectively kills various types of malignant cells. We used CAP-activated media (PAM) to utilize a range of the generated short- and long-lived reactive species. Specific antibodies, small molecule inhibitors and CRISPR/Cas9 gene-editing approaches showed an essential role for receptor tyrosine kinases, especially epidermal growth factor (EGF) receptor, in mediating triple negative breast cancer (TNBC) cell responses to PAM. EGF also dramatically enhanced the sensitivity and specificity of PAM against TNBC cells. Site-specific phospho-EGFR analysis, signal transduction inhibitors and reconstitution of EGFR-depleted cells with EGFR-mutants confirmed the role of phospho-tyrosines 992/1173 and phospholipase C gamma signaling in up-regulating levels of reactive oxygen species above the apoptotic threshold. EGF-triggered EGFR activation enhanced the sensitivity and selectivity of PAM effects on TNBC cells. The proposed approach based on the synergy of CAP and EGFR-targeted therapy may provide new opportunities to improve the clinical management of TNBC.

Effects of cold atmospheric-pressure plasma in combination with doxorubicin drug against breast cancer cells in vitro and invivo

Cold atmospheric plasma (CAP) has been suggested for medical applications that can be applied indirectly through plasma-activated medium (PAM) and recently it has been introduced as an innovative therapeutic approach for all cancer types. Studies have exhibited that ROS/RNS are key factors in CAP-dependent apoptosis; nevertheless, ROS/RNS stability are weak. Combination therapy is considered an effective strategy to overcome these problems. In the present research, we revealed that the combination of CAP and doxorubicin (DOX) significantly induces the apoptosis of breast cancer cells both in vitro and in vivo. Our results indicated that both Ar and He/O2 CAP treatment as well as DOX drug alone reduced cell growth. CAP/PAM treatment in combination with DOX induced apoptosis in MCF-7 breast cancer cells and 4T1-implanted BALB/c mice, resulting in a significant increase in antitumor activity. The apoptotic effects of CAP-DOX on MCF-7 cells were inferred from altered expression of BAX and cleaved-caspase-3 which mechanistically take place through the mitochondrial pathway mediated by Bcl-2 family members. Besides, the BAX/BCL-2 ratio is significantly higher in the simultaneous treatment of CAP and DOX. This ratio was equal to 2.82 ± 0.24, 2.54 ± 0.30, and 11.27 ± 0.31 for treatment with DOX, He/O2 plasma, and combination treatment, respectively. Additionally, the tumor growth rate of He/O2-PAM + DOX and Ar-PAM + DOX treatments was significantly inhibited by PAM-injection, and the tumor growth rate of PAM alone or DOX alone was slightly reduced. It can be concluded that the effect of PAM + DOX may increase the anticancer activity and decrease the dose required for the chemotherapeutic treatment.

Atmospheric pressure pin-to-plate cold plasma effect on physicochemical, functional, pasting, thermal, and structural characteristics of proso-millet starch

The present work aimed to study the influence of atmospheric pressure pin-to-plate cold plasma on the physicochemical (pH, moisture, and amylose content), functional (water & oil binding capacity, solubility & swelling power, paste clarity on storage, pasting), powder flow, thermal and structural (FTIR, XRD, and SEM) characteristics at an input voltage of 170-230 V for 5-15 min. The starch surface modification by cold plasma was seen in the SEM images which cause the surge in WBC (1.54 g/g to 1.93 g/g), OBC (2.22 g/g to 2.79 g/g), solubility (3.05-5.38% at 70 °C; 37.11-52.98% at 90 °C) and swelling power (5.39-7.83% at 70 °C; 25.67-35.33% at 90 °C) of starch. Reduction in the amylose content (27.82% to 25.07%) via plasma-induced depolymerization resists the retrogradation tendency, thereby increasing the paste clarity (up to ̴ 39%) during the 5 days of refrigerated storage. However, the paste viscosity is reduced after cold plasma treatment yielding low-strength starch pastes. The relative crystallinity of starch increased (37.35% to 45.36%) by the plasma-induced fragmented starch granules which would aggregate and broaden the gelatinization temperature, but these starch fragments reduced the gelatinization enthalpy. The fundamental starch structure is conserved as seen in FTIR spectra. Thus, cold plasma aids in the production of soluble, low-viscous, stable, and clear paste-forming depolymerized proso-millet starch.

Potential and mechanism of disinfection by-products removal in drinking water by bubbling corona discharge

Disinfection by-products (DBPs) with significant teratogenic and carcinogenic properties have become a growing concern among the public. As an efficient and environmentally friendly technology, non-thermal plasma offers potential for removing emerging micro-pollutants. In this study, the degradation performance of bubbling corona discharge was evaluated on 24 halogenated alicyclic and aliphatic DBPs present in drinking water at concentrations ranging from ng/L to μg/L. The degradation of DBPs followed pseudo-first-order kinetics with rate constants (kobs) in the descending order of halonitromethanes (HNMs), halogenated benzoquinones (HBQs), haloacetonitriles, trihalomethanes (THMs), haloketones, halogenated aldehydes, and haloacetic acids (HAAs). THMs, HNMs, and HBQs were effectively removed within 5 min under a discharge power of 28 W. Degradation rates achieved by plasma treatment surpass those of other conventional treatment technologies. The required energy consumption was in the range of 5-30 kW·h/m3/order. Furthermore, the study investigated the effects of discharge power, initial concentration, and economic analysis on the degradation of four selected DBPs as representatives of mono-, di- and multi-carbon-containing DBPs, namely chloroform (TCM) and bromoform (TBM), tribromoacetic acid (TBAA), and 2,3,5,6-tetrachloro-1,4-benzoquinone (TetraC-BQ). Reactive radicals in the plasma system were investigated using electron paramagnetic resonance, optical emission spectroscopy, fluorimetry, and radical scavengers. Hydrated electrons and hydroxyl radicals played an important role in the removal of DBPs. The intermediates generated during the degradation of TCM, TBM, TBAA, and TetraC-BQ were identified, and the possible degradation pathways for mono- and binary C-DBPs and HBQs were deduced. The breakdown of HBQs did not produce secondary contamination with aliphatic DBPs. The carbon in DBPs was primarily converted to formic acid, acetic acid, and oxalic acid, and the halogens were mainly converted to halogen ions. Additionally, luminescent bacteria toxicity testing confirmed that plasma treatment could reduce the acute toxicity of water samples. These findings demonstrate the potential of plasma treatment as a post-treatment device at the household level.

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.

Medical gas plasma technology: Roadmap on cancer treatment and immunotherapy

Despite continuous therapeutic progress, cancer remains an often fatal disease. In the early 2010s, first evidence in rodent models suggested promising antitumor action of gas plasma technology. Medical gas plasma is a partially ionized gas depositing multiple physico-chemical effectors onto tissues, especially reactive oxygen and nitrogen species (ROS/RNS). Today, an evergrowing body of experimental evidence suggests multifaceted roles of medical gas plasma-derived therapeutic ROS/RNS in targeting cancer alone or in combination with oncological treatment schemes such as ionizing radiation, chemotherapy, and immunotherapy. Intriguingly, gas plasma technology was recently unraveled to have an immunological dimension by inducing immunogenic cell death, which could ultimately promote existing cancer immunotherapies via in situ or autologous tumor vaccine schemes. Together with first clinical evidence reporting beneficial effects in cancer patients following gas plasma therapy, it is time to summarize the main concepts along with the chances and limitations of medical gas plasma onco-therapy from a biological, immunological, clinical, and technological point of view.

Neuroprotective Effects of Phenolic Antioxidant Tert-butylhydroquinone (tBHQ) in Brain Diseases

Human life and health are gravely threatened by brain diseases. The onset and progression of the illnesses are influenced by a variety of factors, including pathogenic causes, environmental factors, mental issues, etc. According to scientific studies, neuroinflammation and oxidative stress play a significant role in the development and incidence of brain diseases by producing pro-inflammatory cytokines and oxidative tissue damage to induce inflammation and apoptosis. Neuroinflammation, oxidative stress, and oxidative stress-related changes are inseparable factors in the etiology of several brain diseases. Numerous neurodegenerative diseases have undergone substantial research into the therapeutic alternatives that target oxidative stress, the function of oxidative stress, and the possible therapeutic use of antioxidants. Formerly, tBHQ is a synthetic phenolic antioxidant, which has been widely used as a food additive. According to recent researches, tBHQ can suppress the processes that lead to neuroinflammation and oxidative stress, which offers a fresh approach to treating brain diseases. In order to achieve the goal of decreasing inflammation and apoptosis, tBHQ is a specialized nuclear factor erythroid 2-related factor (Nrf2) activator that decreases oxidative stress and enhances antioxidant status by upregulating the Nrf2 gene and reducing nuclear factor kappa-B (NF-κB) activity. This article reviews the effects of tBHQ on neuroinflammation and oxidative stress in recent years and looks into how tBHQ inhibits neuroinflammation and oxidative stress through human, animal, and cell experiments to play a neuroprotective role in Alzheimer's disease (AD), stroke, depression, and Parkinson's disease (PD). It is anticipated that this article will be useful as a reference for upcoming research and the creation of drugs to treat brain diseases.

Efficacy of Plasma-Treated Water against Salmonella Typhimurium: Antibacterial Activity, Inhibition of Invasion, and Biofilm Disruption

Plasma-treated water (PTW) has emerged as a potential sanitizing agent. This study evaluated antibacterial activity, inhibition of invasion, and biofilm disruption effects of PTW against Salmonella Typhimurium. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined for different PTW types. Time-kill assays were conducted to assess bactericidal effects, while polarized Caco-2 cells were used to evaluate invasion inhibition. Biofilm formation and cell viability were examined following PTW treatment using Salmonella Typhimurium isolates, while biofilm disruption and regrowth prevention were investigated using the Bioflux system. PTW exhibited antibacterial activity against all Salmonella Typhimurium isolates, with MICs of 25% for PTW1 and PTW2, and 50% for PTW3, PTW4, and PTW5. MBCs of 50% in media were observed for all PTW types. Undiluted PTW1 and PTW2 showed the highest bactericidal capacity, significantly reduced Salmonella viability, and completely inhibited bacterial invasion, while PTW3 and PTW5 also showed significant invasion reduction. Bioflux experiments confirmed the eradication of biofilms by PTW1 and PTW2, with no regrowth observed 72 h after PTW was removed. PTW demonstrated significant antibacterial activity, inhibition of invasion, biofilm disruption, and reduction of bacterial viability against Salmonella Typhimurium. This highlights PTW's potential as an effective sanitizer for reducing Salmonella contaminations.

Catalytically enhanced direct degradation of nitro-based antibacterial agents using dielectric barrier discharge cold atmospheric pressure plasma and rhenium nanoparticles

The common utilization of antimicrobial agents in medicine and veterinary creates serious problems with multidrug resistance spreading among pathogens. Bearing this in mind, wastewaters have to be completely purified from antimicrobial agents. In this context, a dielectric barrier discharge cold atmospheric pressure plasma (DBD-CAPP) system was used in the present study as a multifunctional tool for the deactivation of nitro-based pharmacuticals such as furazolidone (FRz) and chloramphenicol (ChRP) in solutions. A direct approach was applied to this by treating solutions of the studied drugs by DBD-CAPP in the presence of the ReO4- ions. It was found that Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), generated in the DBD-CAPP-treated liquid, played a dual role in the process. On the one hand, ROS and RNS led to the direct degradation of FRz and ChRP, and on the other hand, they enabled the production of Re nanoparticles (ReNPs). The produced in this manner ReNPs consisted of catalytically active Re+4, Re+6, and Re+7 species which allowed the reduction of -NO2 groups contained in the FRz and ChRP. Unlike the DBD-CAPP, the catalytically enhanced DBD-CAPP led to almost FRz and ChRP removals from studied solutions. The catalytic boost was particularly highlighted when catalyst/DBD-CAPP was operated in the synthetic waste matrix. Re-active sites in this scenario led to the facilitated deactivation of antibiotics, achieving significantly higher FRz and ChRP removals than DBD-CAPP on its own.

Effects of Plasma-Activated Water Treatment on the Inactivation of Microorganisms Present on Cherry Tomatoes and in Used Wash Solution

Herein, we investigated the potential of plasma-activated water (PAW) as a wash solution for the microbial decontamination of cherry tomatoes. We analyzed the efficacy of PAW as a bactericidal agent based on reactive species and pH. Immersion for 5 min in PAW15 (generated via plasma activation for 15 min) was determined as optimal for microbial decontamination of fresh produce. The decontamination efficacy of PAW15 exceeded those of mimic solutions with equivalent reactive species concentrations and pH (3.0 vs. 1.7 log reduction), suggesting that the entire range of plasma-derived reactive species participates in decontamination rather than a few reactive species. PAW15-washing treatment achieved reductions of 6.89 ± 0.36, 7.49 ± 0.40, and 5.60 ± 0.05 log₁₀ CFU/g in the counts of Bacillus cereus, Salmonella sp., and Escherichia coli O157:H7, respectively, inoculated on the surface of cherry tomatoes, with none of these strains detected in the wash solution. During 6 days of 25 °C storage post-washing, the counts of aerobic bacteria, yeasts, and molds were below the detection limit. However, PAW15 did not significantly affect the viability of RAW264.7 cells. These results demonstrate that PAW effectively inactivates microbes and foodborne pathogens on the surface of cherry tomatoes and in the wash solution. Thus, PAW could be used as an alternative wash solution in the fresh produce industry without cross-contamination during washing and environmental contamination by foodborne pathogens or potential risks to human health.

Photosensitive Dye as an Ideal Peroxymonosulfate Activator for Efficient Self-Degradation: A Novel Idea of Using Waste to Treat Waste

Commonly used peroxydisulfate (PS) or peroxymonosulfate (PMS) activation methods have been limited in their practical application due to certain drawbacks, such as high cost, high energy consumption and secondary pollution. In this study, a catalyst-free alizarin green (AG) self-activating PMS catalytic system was constructed based on photosensitization properties of dye, which ultimately achieved efficient degradation of the dye activator, also the target pollutant. Here, 52.5% of the 100 mL mixture of 10 mg/L AG decomposed within 60 min with 1 mM PMS under visible-light irradiation, thereby showing a strong pH adaptation. Mechanism of AG self-activating PMS was revealed that the photo-excited AG can effectively transfer photo-induced electrons to PMS for its activation, which generates reactive oxidizing species dominated by singlet oxygen (¹O₂), and supplemented by hydroxyl radical (•OH), superoxide radical (O₂^•-) and sulfate radical (SO₄^•-) to realize the efficient self-degradation of the dye pollutants. Moreover, such self-catalytic system operated well under natural sunlight irradiation, indicating the great application potential in the actual wastewater treatment. Herein, photosensitive dye acted as an ideal PMS activator realizing its efficient self-degradation, which provides a novel idea of "using waste to treat waste" for developing wastewater treatment process in a high-efficiency and low-consumption way.

Glutamine Deprivation Synergizes the Anticancer Effects of Cold Atmospheric Plasma on Esophageal Cancer Cells

Esophageal cancer is a highly aggressive malignancy with a low response to standard anti-cancer therapies. There is an unmet need to develop new therapeutic strategies to improve the clinical outcomes of current treatments. Cold atmospheric plasma (CAP) is a promising approach for cancer treatment, and has displayed anticancer efficacy in multiple preclinical models. Recent studies have shown that the efficacy of CAP is positively correlated with intracellular reactive oxygen species (ROS) levels. This suggests that aggressively increasing intracellular ROS levels has the potential to further improve CAP-mediated anticancer efficacy. Glutamine plays an important role in cellular ROS scavenging after being converted to glutathione (GSH, a well-described antioxidant) under physiological conditions, so reducing intracellular glutamine levels seems to be a promising strategy. To test this hypothesis, we treated esophageal cancer cells with CAP while controlling the supply of glutamine. The results showed that glutamine did affect the anticancer effect of CAP, and the combination of CAP stimulation and glutamine deprivation significantly inhibited the proliferation of esophageal cancer cells compared to the control group (p < 0.05). Furthermore, flow cytometric analysis documented a significant increase in more than 10% in apoptosis and necrosis of esophageal cancer cells after this synergistic treatment compared to the control group (p < 0.05). Thus, these results provide the first direct evidence that the biological function of CAP can be modulated by glutamine levels and that combined CAP stimulation and glutamine deprivation represent a promising strategy for the future treatment of esophageal cancer.

Toxic reactive oxygen species stresses for reconfiguring central carbon metabolic fluxes in foodborne bacteria: Sources, mechanisms and pathways

The toxic reactive oxygen species (toxROS) is the reactive oxygen species (ROS) beyond the normal concentration of cells, which has inactivation and disinfection effects on foodborne bacteria. However, foodborne bacteria can adapt and survive by physicochemical regulation of antioxidant systems, especially through central carbon metabolism (CCM), which is a significant concern for food safety. It is thus necessary to study the antioxidant regulation mechanisms of CCM in foodborne bacteria under toxROS stresses. Therefore, the purpose of this review is to provide an update and comprehensive overview of the reconfiguration of CCM fluxes in foodborne bacteria that respond to different toxROS stresses. In this review, two key types of toxROS including exogenous toxROS (exo-toxROS) and endogenous toxROS (endo-toxROS) are introduced. Exo-toxROS are produced by disinfectants, such as H₂O₂ and HOCl, or during food non-thermal processing such as ultraviolet (UV/UVA), cold plasma (CP), ozone (O₃), electrolyzed water (EW), pulsed electric field (PEF), pulsed light (PL), and electron beam (EB) processing. Endo-toxROS are generated by bioreagents such as antibiotics (aminoglycosides, quinolones, and β-lactams). Three main pathways for CCM in foodborne bacteria under the toxROS stress are also highlighted, which are glycolysis (EMP), pentose phosphate pathway (PPP), and tricarboxylic acid cycle (TCA). In addition, energy metabolisms throughout these pathways are discussed. Finally, challenges and future work in this area are suggested. It is hoped that this review should be beneficial in providing insights for future research on bacterial antioxidant CCM defence under both exo-toxROS stresses and endo-toxROS stresses.

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.

Cold Atmospheric Plasma Jet Treatment Improves Human Keratinocyte Migration and Wound Closure Capacity without Causing Cellular Oxidative Stress

Cold Atmospheric Plasma (CAP) is an emerging technology with great potential for biomedical applications such as sterilizing equipment and antitumor strategies. CAP has also been shown to improve skin wound healing in vivo, but the biological mechanisms involved are not well known. Our study assessed a possible effect of a direct helium jet CAP treatment on keratinocytes, in both the immortalized N/TERT-1 human cell line and primary keratinocytes obtained from human skin samples. The cells were covered with 200 µL of phosphate buffered saline and exposed to the helium plasma jet for 10−120 s. In our experimental conditions, micromolar concentrations of hydrogen peroxide, nitrite and nitrate were produced. We showed that long-time CAP treatments (≥60 s) were cytotoxic, reduced keratinocyte migration, upregulated the expression of heat shock protein 27 (HSP27) and induced oxidative cell stress. In contrast, short-term CAP treatments (<60 s) were not cytotoxic, did not affect keratinocyte proliferation and differentiation, and did not induce any changes in mitochondria, but they did accelerate wound closure in vitro by improving keratinocyte migration. In conclusion, these results suggest that helium-based CAP treatments improve wound healing by stimulating keratinocyte migration. The study confirms that CAP could be a novel therapeutic method to treat recalcitrant wounds.

Plasma activated medium prepared by a bipolar microsecond-pulsed atmospheric pressure plasma jet array induces mitochondria-mediated apoptosis in human cervical cancer cells

Plasma activated medium (PAM) was prepared by a bipolar microsecond-pulsed atmospheric pressure plasma jet (APPJ) array source and was utilized for cancer cell treatment. APPJ array-produced plasma were characterized. APPJ array treatment of three different solutions (deionized water (DW), HBSS (serum-free Hanks’ balanced salt solution), and DMEM (Dulbecco’s Modified Eagle Medium) + 10% FBS (fetal bovine serum)) were performed to induce the changes in the concentration of reactive oxygen and nitrogen species (RONS) as functions of the operating parameters. Human cervical cancer cells (HeLa) injected with plasma-treated media were investigated for changes in cell viability using MTT assay. It was observed that PAM-induced ROS can regulate the protein expression associated with mitochondria, and PAM causes apoptosis through Cyto C/JNK/p38 signaling on human cervical cancer cells.

Effect of Saccharides Coating on Antibacterial Potential and Drug Loading and Releasing Capability of Plasma Treated Polylactic Acid Films

More than half of the hospital-associated infections worldwide are related to the adhesion of bacteria cells to biomedical devices and implants. To prevent these infections, it is crucial to modify biomaterial surfaces to develop the antibacterial property. In this study, chitosan (CS) and chondroitin sulfate (ChS) were chosen as antibacterial coating materials on polylactic acid (PLA) surfaces. Plasma-treated PLA surfaces were coated with CS either direct coating method or the carbodiimide coupling method. As a next step for the combined saccharide coating, CS grafted samples were immersed in ChS solution, which resulted in the polyelectrolyte complex (PEC) formation. Also in this experiment, to test the drug loading and releasing efficiency of the thin film coatings, CS grafted samples were immersed into lomefloxacin-containing ChS solution. The successful modifications were confirmed by elemental composition analysis (XPS), surface topography images (SEM), and hydrophilicity change (contact angle measurements). The carbodiimide coupling resulted in higher CS grafting on the PLA surface. The coatings with the PEC formation between CS-ChS showed improved activity against the bacteria strains than the separate coatings. Moreover, these interactions increased the lomefloxacin amount adhered to the film coatings and extended the drug release profile. Finally, the zone of inhibition test confirmed that the CS-ChS coating showed a contact killing mechanism while drug-loaded films have a dual killing mechanism, which includes contact, and release killing.

The Effect of Gap Distance between a Pin and Water Surface on the Inactivation of Escherichia coli Using a Pin-to-Water Plasma

Atmospheric plasmas have been applied for the inactivation of microorganisms. Industrials demand to investigate the relation of the key reactive species induced by plasmas and the operating parameters including boundary conditions in order to control plasma treatment processes. In this study, we investigated the effect of gap distance between a pin-electrode and water surface on inactivation efficacy. When the gap distance decreased from 5 mm to 1 mm, the reduction of Escherichia coli (E. coli) was increased to more than 4 log CFU/mL. The reactive oxygen species measured optically and spectrophotometrically were influenced by gap distance. The results from electron spin resonance (ESR) analysis showed that the pin-to-water plasma generated hydroxyl radical (OH•) and singlet oxygen (¹O₂) in the water and superoxide radical (O₂⁻•) served as a precursor of OH•. The inactivation of E. coli was significantly alleviated by sodium azide (¹O₂ scavenger), indicating that ¹O₂ contributes the most to bacterial inactivation. These findings provide a potentially effective strategy for bacterial inactivation using a pin-to-water plasma.

Cold Atmospheric Plasma-Activated Media Improve Paclitaxel Efficacy on Breast Cancer Cells in a Combined Treatment Model

The use of plasma-activated media (PAM), an alternative to direct delivery of cold atmospheric plasma to cancer cells, has recently gained interest in the plasma medicine field. Paclitaxel (PTX) is used as a chemotherapy of choice for various types of breast cancers, which is the leading cause of mortality in females due to cancer. In this study, we evaluated an alternative way to improve anti-cancerous efficiency of PTX by association with PAM, the ultimate achievement being a better outcome in killing tumoral cells at smaller doses of PTX. MCF-7 and MDA-MB-231 cell lines were used, and the outcome was measured by cell viability (MTT assay), the survival rate (clonogenic assay), apoptosis occurrence, and genotoxicity (COMET assay). Treatment consisted of the use of PAM in combination with under IC50 doses of PTX in short- and long-term models. The experimental data showed that PAM had the capacity to improve PTX's cytotoxicity, as viability of the breast cancer cells dropped, an effect maintained in long-term experiments. A higher frequency of apoptotic, dead cells, and DNA fragmentation was registered in cells treated with the combined treatment as compared with those treated only with PT. Overall, PAM had the capacity to amplify the anti-cancerous effect of PTX.

Low-Temperature Plasma-Activated Medium Inhibited Proliferation and Progression of Lung Cancer by Targeting the PI3K/Akt and MAPK Pathways

Low-temperature plasma, an engineered technology to generate various reactive species, is actively studied in cancer treatment in recent years, yet mainly by using a traditional 2D cell culture system. In this study, we explored the effect of the plasma-activated medium (PAM) on lung cancer cells in vitro and in vivo by using a 3D cell culture model. The results showed that PAM markedly inhibited 3D spheroid formation and downregulated stemness-related gene expression. We found that reactive oxygen species (ROS) penetrated throughout the whole spheroids and induced cell death surrounding and in the core of the tumor spheroid. Besides, PAM treatment suppressed migration and invasion of lung cancer cells and downregulated epithelial-mesenchymal transition- (EMT-) related gene expression. In the mouse xenograft model, the tumor volume was significantly smaller in the PAM-treated group compared with the control group. By using transcriptome sequencing, we found that PI3K/Akt and MAPK pathways were involved in the inhibition effects of PAM on lung cancer cells. Therefore, our results indicated that PAM exhibits potential anticancer effects on lung cancer and provides insight into further exploration of PAM-induced cell death and translational preclinical use.

Irrigation of peritoneal cavity with cold atmospheric plasma treated solution effectively reduces microbial load in rat acute peritonitis model

Accurate and timely diagnosis of appendicitis in children can be challenging, which leads to delayed admittance or misdiagnosis that may cause perforation. Surgical management involves the elimination of the focus (appendectomy) and the reduction of the contamination with peritoneal irrigation to prevent sepsis. However, the validity of conventional irrigation methods is being debated, and novel methods are needed. In the present study, the use of cold plasma treated saline solution as an intraperitoneal irrigation solution for the management of acute peritonitis was investigated. Chemical and in vitro microbiological assessments of the plasma-treated solution were performed to determine the appropriate plasma treatment time to be used in in-vivo experiments. To induce acute peritonitis in rats, the cecal ligation and perforation (CLP) model was used. Sixty rats were divided into six groups, namely, sham operation, plasma irrigation, CLP, dry cleaning after CLP, saline irrigation after CLP, and plasma-treated saline irrigation after CLP group. The total antioxidant and oxidant status, oxidative stress index, microbiological, and pathological evaluations were performed. Findings indicated that plasma-treated saline contains reactive species, and irrigation with plasma-treated saline can effectively inactivate intraperitoneal contamination and prevent sepsis with no short-term local and/or systemic toxicity.

Cold helium plasma jet does not stimulate collagen remodeling in a 3D human dermal substitute

Cold Atmospheric Plasma (CAP) is an emerging physical approach displaying encouraging antitumor and wound healing effects both in vitro and in vivo. In this study, we assessed the potential of direct CAP to remodel skin collagens using an original tissue-engineered human dermal substitute model rich in endogenous extracellular matrix (ECM) covered with 600 µl of culture medium and treated with CAP for 30 and 120 s. Our results indicated that Reactive Oxygen and Nitrogen Species (RONS) such as H2O2, NO3- and NO2- were produced in the medium during treatment. It appeared that in the CAP-treated dermal substitutes 1) cell viability was not altered, 2) pro-collagen I secretion was not modified over 48 h of culture after treatment, 3) global activity of matrix metalloproteinases MMPs was not modulated over 48 h after treatment, and 4) no change in hydroxyproline content was observed over 5 days after treatment. In order to confirm the efficiency of our device, we showed that the plasma-activated culture medium induced cell apoptosis and growth delay using a 3D human tumor spheroid model. In conclusion, no effect of direct CAP treatment was monitored on dermal ECM production and degradation, indicating that CAP does not stimulate collagen remodeling at the tissue scale.

Cold Atmospheric Plasma Attenuates Breast Cancer Cell Growth Through Regulation of Cell Microenvironment Effectors

Breast cancer exists in multiple subtypes some of which still lack a targeted and effective therapy. Cold atmospheric plasma (CAP) has been proposed as an emerging anti-cancer treatment modality. In this study, we investigated the effects of direct and indirect CAP treatment driven by the advantageous nanosecond pulsed discharge on breast cancer cells of different malignant phenotypes and estrogen receptor (ER) status, a major factor in the prognosis and therapeutic management of breast cancer. The main CAP reactive species in liquid (i.e. H2O2, NO2−/NO3−) and gas phase were determined as a function of plasma operational parameters (i.e. treatment time, pulse voltage and frequency), while pre-treatment with the ROS scavenger NAC revealed the impact of ROS in the treatment. CAP treatment induced intense phenotypic changes and apoptosis in both ER+ and ER- cells, which is associated with the mitochondrial pathway as evidenced by the increased Bax/Bcl-2 ratio and cleavage of PARP-1. Interestingly, CAP significantly reduced CD44 protein expression (a major cancer stem cell marker and matrix receptor), while differentially affected the expression of proteases and inflammatory mediators. Collectively, the findings of the present study suggest that CAP suppresses breast cancer cell growth and regulates several effectors of the tumor microenvironment and thus it could represent an efficient therapeutic approach for distinct breast cancer subtypes.

The role of reactive oxygen species in the immunity induced by nano-pulse stimulation

Reactive oxygen species (ROS) are byproducts of tumor cells treated with Nano-Pulse Stimulation (NPS). Recently, ROS have been suggested as a contributing factor in immunogenic cell death and T cell-mediated immunity. This research further investigated the role of NPS induced ROS in antitumor immunity. ROS production in 4T1-luc breast cancer cells was characterized using three detection reagents, namely, Amplex Red, MitoSox Red, and Dihydroethidium. The efficiency of ROS quenching was evaluated in the presence or absence of ROS scavengers and/or antioxidants. The immunogenicity of NPS treated tumor cells was assessed by ex vivo dendritic cell activation, in vivo vaccination assay and in situ vaccination with NPS tumor ablation. We found that NPS treatment enhanced the immunogenicity of 4T1-luc mouse mammary tumor, resulted in a potent in situ vaccination protection and induced long-term T cell immunity. ROS production derived from NPS treated breast cancer cells was an electric pulse dose-dependent phenomenon. Noticeably, the dynamic pattern of hydrogen peroxide production was different from that of superoxide production. Interestingly, regardless of NPS treatment, different ROS scavengers could either block or promote ROS production and stimulate or inhibit tumor cell growth. The activation of dendritic cells was not influenced by blocking ROS generation. The results from in vivo vaccination with NPS treated cancer cells suggests that ROS generation was not a prerequisite for immune protection.

Effect of Plasma-Activated Solution Treatment on Cell Biology of Staphylococcus aureus and Quality of Fresh Lettuces

This study aimed to investigate effects of plasma-activated solution (PAS) on the cell biology of Staphylococcus aureus and qualities of fresh lettuce leaves. PAS was prepared by dielectric barrier discharge plasma and incubated with S. aureus for 10–30 min or with lettuces for 10 min. Effects on cell biology were evaluated with microscopic images, cell integrity, and chemical modification of cellular components. Effects on lettuce quality were estimated with the viable microbial counts, color, contents of vitamin C and chlorophyll, and surface integrity. PAS reduced S. aureus population by 4.95-log and resulted in increased cell membrane leakage. It also resulted in increased contents of reactive oxygen species in cells, C=O bonds in peptidoglycan, and 8-hydroxydeoxyguanosine content in cellular DNA, and reduced ratios of unsaturated/saturated fatty acids in the cell membrane. PAS treatment reduced bacterial load on fresh lettuce and had no negative effects on the quality. Data suggest that PAS can be used for the disinfection of ready-to-eat fresh vegetables.

Hitchhiking Nanoparticles: Mesenchymal Stem Cell-Mediated Delivery of Theranostic Nanoparticles

Nanotechnology has emerged as a promising solution to permanent elimination of cancer. However, nanoparticles themselves lack specificity to tumors. Due to enhanced migration to tumors, mesenchymal stem cells (MSCs) were suggested as cell-mediated delivery vehicles of nanoparticles. In this study, we have constructed a complex composed of photoluminescent quantum dots (QDs) and a photosensitizer chlorin e6 (Ce6) to obtain multifunctional nanoparticles, combining cancer diagnostic and therapeutic properties. QDs serve as energy donors-excited QDs transfer energy to the attached Ce6 via Förster resonance energy transfer, which in turn generates reactive oxygen species. Here, the physicochemical properties of the QD-Ce6 complex and singlet oxygen generation were measured, and the stability in protein-rich media was evaluated, showing that the complex remains the most stable in protein-free medium. In vitro studies on MSC and cancer cell response to the QD-Ce6 complex revealed the complex-loaded MSCs' potential to transport theranostic nanoparticles and induce cancer cell death. In vivo studies proved the therapeutic efficacy, as the survival of tumor-bearing mice was statistically significantly increased, while tumor progression and metastases were slowed down.

Non-thermal atmospheric pressure plasma activates Wnt/β-catenin signaling in dermal papilla cells

There is an unmet need for novel, non-pharmacological therapeutics to treat alopecia. Recent studies have shown the potential biological benefits of non-thermal atmospheric pressure plasma (NTAPP), including wound healing, angiogenesis, and the proliferation of stem cells. We hypothesized that NTAPP might have a stimulatory effect on hair growth or regeneration. We designed an NTAPP-generating apparatus which is applicable to in vitro and in vivo experiments. The human dermal papilla (DP) cells, isolated fresh hair follicles, and mouse back skin were exposed with the NTAPP. Biological outcomes were measured using RNA-sequencing, RT-PCR, Western blots, and immunostaining. The NTAPP treatment increased the expression levels of Wnt/β-catenin pathway-related genes (AMER3, CCND1, LEF1, and LRG1) and proteins (β-catenin, p-GSK3β, and cyclin D1) in human DP cells. In contrast, inhibitors of Wnt/β-catenin signaling, endo-IWR1 and IWP2, attenuated the levels of cyclin D1, p-GSK3β, and β-catenin proteins induced by NTAPP. Furthermore, we observed that NTAPP induced the activation of β-catenin in DP cells of hair follicles and the mRNA levels of target genes of the β-catenin signaling pathway (CCND1, LEF1, and TCF4). NTAPP-treated mice exhibited markedly increased anagen induction, hair growth, and the protein levels of β-catenin, p-GSK3β, p-AKT, and cyclin D1. NTAPP stimulates hair growth via activation of the Wnt/β-catenin signaling pathway in DP cells. These findings collectively suggest that NTAPP may be a potentially safe and non-pharmacological therapeutic intervention for alopecia.

The Role of HNO2 in the Generation of Plasma-Activated Water by Air Transient Spark Discharge

Transient spark (TS), a DC-driven self-pulsing discharge generating a highly reactive atmospheric pressure air plasma, was employed as a rich source of NOx. In dry air, TS generates high concentrations of NO and NO2, increasing approximately linearly with increasing input energy density (Ed), reaching 1200 and 180 ppm of NO and NO2, at Ed = 400 J/L, respectively. In humid air, the concentration of NO2 decreased down to 120 ppm in favor of HNO2 that reached approximately 100 ppm at Ed = 400 J/L. The advantage of TS is its capability of simultaneous generation of the plasma and the formation of microdroplets by the electrospray (ES) of water directly inside the discharge zone. The TS discharge can thus efficiently generate plasma-activated water (PAW) with high concentration of H2O2−(aq), NO2−(aq) and NO3−(aq), because water microdroplets significantly increase the plasma-liquid interaction interface. This enables a fast transfer of species such as NO, NO2, HNO2 from the gas into water. In this study, we compare TS with water ES in a one stage system and TS operated in dry or humid air followed by water ES in a two-stage system, and show that gaseous HNO2, rather than NO or NO2, plays a major role in the formation of NO2−(aq) in PAW that reached the concentration up to 2.7 mM.

Cold Atmospheric Plasma Changes the Amino Acid Composition of Solutions and Influences the Anti-Tumor Effect on Melanoma Cells

Cold Atmospheric Plasma (CAP) is an ionized gas near room temperature. Its anti-tumor effect can be transmitted either by direct treatment or mediated by a plasma-treated solution (PTS), such as treated standard cell culture medium, which contains different amino acids, inorganic salts, vitamins and other substances. Despite extensive research, the active components in PTS and its molecular or cellular mechanisms are not yet fully understood. The purpose of this study was the measurement of the reactive species in PTS and their effect on tumor cells using different plasma modes and treatment durations. The PTS analysis yielded mode- and dose-dependent differences in the production of reactive oxygen and nitrogen species (RONS), and in the decomposition and modification of the amino acids Tyrosine (Tyr) and Tryptophan (Trp). The Trp metabolites Formylkynurenine (FKyn) and Kynurenine (Kyn) were produced in PTS with the 4 kHz (oxygen) mode, inducing apoptosis in Mel Im melanoma cells. Nitrated derivatives of Trp and Tyr were formed in the 8 kHz (nitrogen) mode, elevating the p16 mRNA expression and senescence-associated ß-Galactosidase staining. In conclusion, the plasma mode has a strong impact on the composition of the active components in PTS and affects its anti-tumor mechanism. These findings are of decisive importance for the development of plasma devices and the effectiveness of tumor treatment.

FeSe2 nanosheets as a bifunctional platform for synergistic tumor therapy reinforced by NIR-II light

Multi-functionality has been a constant pursuit in the development of next-generation drug carriers, as it will bring the potential for combination therapy by integrating diverse therapeutic modes. In this work, FeSe₂ nanosheets (NSs) have been prepared as a bifunctional platform to investigate their use in synergistic cancer therapy. Bifunctional FeSe₂ NSs exhibit exceptional Fenton-like activity that generates cytotoxic hydroxyl radical (˙OH) and strong broad photothermal performance including the second-infrared (NIR-II) spectral range, wherein the ˙OH production can be enhanced by NIR-II light irradiation. Furthermore, doxorubicin (DOX) was conjugated onto NSs via a pH-responsive hydrazone bond to achieve preferential drug release in an acidic microenvironment. Upon intratumoral administration, these bifunctional drug-carrying FeSe₂ NSs showed an NIR-II irradiation-reinforced strong tumor suppression effect, and no obvious toxicity to normal tissues was observed. This study provides a new paradigm for the design of advanced drug carriers relying on their inherent physicochemical properties.

Selective Apoptotic Effect of Plasma Activated Liquids on Human Cancer Cell Lines

Plasma medicine is a new field focusing on biomedical and clinical applications of cold gas plasmas, including their anticancer effects. Cold plasmas can be applied directly or indirectly as plasma-activated liquids (PAL). The effects of plasma-activated cell growth medium (PAM) and plasma-activated phosphate buffered saline (PAPBS) were tested, using a plasma pen generating streamer corona discharge in ambient air, on different cancer cell lines (melanoma A375, glioblastoma LN229 and pancreatic cancer MiaPaCa-2) and normal cells (human dermal fibroblasts HDFa). The viability reduction and apoptosis induction were detected in all cancer cells after incubation in PAL. In melanoma cells we focused on detailed insights to the apoptotic pathways. The anticancer effects depend on the plasma treatment time or PAL concentration. The first 30 min of incubation in PAL were enough to start processes leading to cell death. In fibroblasts, no apoptosis induction was observed, and only PAPBS, activated for a longer time, slightly decreased their viability. Effects of PAM and PAPBS on cancer cells showed selectivity compared to normal fibroblasts, depending on correctly chosen activation time and PAL concentration, which is very promising for potential clinical applications. This selectivity effect of PAL is conceivably induced by plasma-generated hydrogen peroxide.

Photoinduced Release of Volatile Organic Compounds from Fatty Alcohols at the Air-Water Interface: The Role of Singlet Oxygen Photosensitized by a Carbonyl Group

Photoinduced interfacial release of volatile organic compounds (VOCs) from surfactants receives emerging concerns. Here, we investigate the photoreaction of 1-nonanol (NOL) as a model surfactant at the air-water interface, especially for the important role of ¹O₂ in the formation of VOCs. The production of VOCs is real-time quantitated. The results indicate that the oxygen content apparently affects the total yields of VOCs during the photoreaction of interfacial NOL. The photoactivity of NOL is about 8 times higher under air than that under nitrogen, which is mainly attributed to the generation of ¹O₂. Additionally, the production of VOCs increased by about 4 times with the existence of the air-water interface. Quenching experiments of ¹O₂ also illustrate the contribution of ¹O₂ to VOC formation, which could reach more than 95% during photoirradiation of NOL. Furthermore, density functional theory calculations show that ¹O₂ generated via energy transfer of photosensitizers can abstract two hydrogen atoms from a fatty alcohol molecule. The energy barrier of this reaction is 72.3 kJ/mol, and its reaction rate coefficient is about 2.742 s^-1 M^-1. ¹O₂ significantly promotes photoinduced oxidation of fatty alcohols and VOC formation through hydrogen abstraction, which provides a new insight into the interfacial photoreaction.

Head and Neck Cancer Cell Death due to Mitochondrial Damage Induced by Reactive Oxygen Species from Nonthermal Plasma-Activated Media: Based on Transcriptomic Analysis

Mitochondrial targeted therapy is a next-generation therapeutic approach for cancer that is refractory to conventional treatments. Mitochondrial damage caused by the excessive accumulation of reactive oxygen species (ROS) is a principle of mitochondrial targeted therapy. ROS in nonthermal plasma-activated media (NTPAM) are known to mediate anticancer effects in various cancers including head and neck cancer (HNC). However, the signaling mechanism of HNC cell death via NTPAM-induced ROS has not been fully elucidated. This study evaluated the anticancer effects of NTPAM in HNC and investigated the mechanism using transcriptomic analysis. The viability of HNC cells decreased after NTPAM treatment due to enhanced apoptosis. A human fibroblast cell line and three HNC cell lines were profiled by RNA sequencing. In total, 1 610 differentially expressed genes were identified. Pathway analysis showed that activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) were upstream regulators. Mitochondrial damage was induced by NTPAM, which was associated with enhancements of mitochondrial ROS (mtROS) and ATF4/CHOP regulation. These results suggest that NTPAM induces HNC cell death through the upregulation of ATF4/CHOP activity by damaging mitochondria via excessive mtROS accumulation, similar to mitochondrial targeted therapy.

Antimicrobial Effect of Plasma-Activated Tap Water on Staphylococcus aureus, Escherichia coli, and Candida albicans

In this study, the potential antimicrobial activity of plasma-activated tap water (PAW) was evaluated against Staphylococcus aureus, Escherichia coli, and Candida albicans. For this, PAW was prepared in a gliding arc plasma system using two treatment conditions: stagnant water and water stirring by a magnetic stirrer, called moving water. Subsequently, their oxidation-reduction potential (ORP), pH, electrical conductivity (σ), and total dissolved solids (TDS) were monitored in different areas of the sample divided according to the depth of the beaker. It was observed that PAW obtained in dynamic conditions showed a more uniform acidity among the evaluated areas with pH 3.53 and ORP of 215 mV. Finally, standardized suspensions of Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 10799), and Candida albicans (SC 5314) were treated with PAW, and the reduction of viable cells determined the antimicrobial effect. Our results indicate that the tap water, activated by plasma treatment using gliding arc, is an excellent inactivation agent in the case of Staphylococcus aureus and Escherichia coli. On the other hand, no significant antimicrobial activity was achieved for Candida albicans.

Effect of radio frequency glow-discharge treatment of titanium on human gingival fibroblasts as a function of distance

The mechanical stability and long-term success of an implant depends on the early healing phase and osseointegration of the bone around it. In addition, a healthy gingival tissue around the implant acts as a barrier that prevents bacteria and pathological byproducts from reaching the implant site. This study investigated the in-vitro attachment and spreading of human gingival fibroblasts (HGF) on bacterial grade polystyrene (PS) at different distances from radio-frequency glow-discharge (RFGD)-treated commercially pure titanium (cpTi) specimens. Controls included sterile cpTi specimens without RFGD treatment. A second set of experiments utilized media transferred to new bacterial grade polystyrene dishes (no cpTi) after the medium was conditioned by exposure to cpTi, either with or without RFGD treatment, for 24 hr. Surface characterization of the dishes was conducted through contact angle measurements and infrared spectroscopy. Cell numbers and surface areas were determined from Image J analysis of multiple microscopic images of fixed, stained cells. The results showed significantly greater numbers and surface areas on bacterial grade PS dishes at distances up to 15 mm from the RFGD-treated cpTi groups than for the controls. Moreover, a significant effect of the conditioned medium from RFGD-treated cpTi versus control cultures was shown on the numbers of fibroblasts attached to bacterial grade polystyrene dishes after 24 hr (p < 0.005) and 48 hr (p = 0.002) incubation. Surface areas of cells exposed to conditioned medium were not significantly different (p ≥ 0.05). Surface characterization of the PS dishes showed a higher value of the critical surface tensions of the treated group when compared to the control group.