Generation Of Nitrogen Species Research Articles

Oxidative Stress, Inflammation, and Autophagy: Potential Targets of Mesenchymal Stem Cells-Based Therapies in Ischemic Stroke.

Ischemic stroke is a leading cause of death worldwide; currently available treatment approaches for ischemic stroke are to restore blood flow, which reduce disability but are time limited. The interruption of blood flow in ischemic stroke contributes to intricate pathophysiological processes. Oxidative stress and inflammatory activity are two early events in the cascade of cerebral ischemic injury. These two factors are reciprocal causation and directly trigger the development of autophagy. Appropriate autophagy activity contributes to brain recovery by reducing oxidative stress and inflammatory activity, while autophagy dysfunction aggravates cerebral injury. Abundant evidence demonstrates the beneficial impact of mesenchymal stem cells (MSCs) and secretome on cerebral ischemic injury. MSCs reduce oxidative stress through suppressing reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation and transferring healthy mitochondria to damaged cells. Meanwhile, MSCs exert anti-inflammation properties by the production of cytokines and extracellular vesicles, inhibiting proinflammatory cytokines and inflammatory cells activation, suppressing pyroptosis, and alleviating blood–brain barrier leakage. Additionally, MSCs regulation of autophagy imbalances gives rise to neuroprotection against cerebral ischemic injury. Altogether, MSCs have been a promising candidate for the treatment of ischemic stroke due to their pleiotropic effect.

The Antimicrobial Effect of Cold Atmospheric Plasma against Dental Pathogens-A Systematic Review of In-Vitro Studies.

Interest in the application of cold atmospheric plasma (CAP) in the medical field has been increasing. Indications in dentistry are surface modifications and antimicrobial interventions. The antimicrobial effect of CAP is mainly attributed to the generation of reactive oxygen and reactive nitrogen species. The aim of this article is to systematically review the available evidence from in-vitro studies on the antimicrobial effect of CAP on dental pathogens. A database search was performed (PubMed, Embase, Scopus). Data concerning the device parameters, experimental set-ups and microbial cultivation were extracted. The quality of the studies was evaluated using a newly designed assessment tool. 55 studies were included (quality score 31–92%). The reduction factors varied strongly among the publications although clusters could be identified between groups of set pathogen, working gases, and treatment time intervals. A time-dependent increase of the antimicrobial effect was observed throughout the studies. CAP may be a promising alternative for antimicrobial treatment in a clinically feasible application time. The introduced standardized protocol is able to compare the outcome and quality of in-vitro studies. Further studies, including multi-species biofilm models, are needed to specify the application parameters of CAP before CAP should be tested in randomized clinical trials.

Jagadis Gupta Kapuganti

Jagadis Gupta Kapuganti

Potential therapeutic effect of Chrysopogon zizanioides (Vetiver) as an anti-inflammatory agent.

Vetiver has a broad history of traditional medicinal uses, but only a handful of research article has reported its utility in treating diseases. But unfortunately, no work has been reported on the anti-inflammatory activity of its plant extract and inflammatory-linked diseases. Hence, the present review focuses on investigating the several presumptions which can be put forward to explain its anti-inflammatory property. Thus, for ensuring the same, all the databases like science direct, PubMed, book chapters, and other authenticated papers were thoroughly studied to present a connection between inflammation and the plant potential. After gaining enough knowledge on pathogenesis of inflammation, it has been observed that the release of mediators from the arachidonic acid metabolism pathway and generation of oxidative and nitrogen species are presented as the main reason for the occurrence of inflammation condition. The stimulation of antioxidant enzyme system network by the plant extract reduces the level of oxidative stress, creating a balance between oxidant and antioxidant system. Moreover, its antimicrobial activity will prevent the biological source of stimulation towards injury and the CNS depressant effect will subside the pain of inflammation. Amalgamating all the factors together, the plant can be utilized as anti-inflammatory can be and also can be proved as a beneficial perspective in the treatment of inflammation-linked disorders.

Antioxidant-Based Therapies in Male Infertility: Do We Have Sufficient Evidence Supporting Their Effectiveness?

Under physiological conditions, reactive oxygen species (ROS) play pivotal roles in various processes of human spermatozoa. Indeed, semen requires the intervention of ROS to accomplish different stages of its maturation. However, ROS overproduction is a well-documented phenomenon occurring in the semen of infertile males, potentially causing permanent oxidative damages to a vast number of biological molecules (proteins, nucleic acids, polyunsaturated fatty acids of biological membrane lipids), negatively affecting the functionality and vitality of spermatozoa. ROS overproduction may concomitantly occur to the excess generation of reactive nitrogen species (RNS), leading to oxidative/nitrosative stress and frequently encountered in various human pathologies. Under different conditions of male infertility, very frequently accompanied by morpho-functional anomalies in the sperm analysis, several studies have provided evidence for clear biochemical signs of damages to biomolecules caused by oxidative/nitrosative stress. In the last decades, various studies aimed to verify whether antioxidant-based therapies may be beneficial to treat male infertility have been carried out. This review analyzed the results of the studies published during the last ten years on the administration of low-molecular-weight antioxidants to treat male infertility in order to establish whether there is a sufficient number of data to justify antioxidant administration to infertile males. An analysis of the literature showed that only 30 clinical studies tested the effects of the administration of low-molecular-weight antioxidants (administered as a single antioxidant or as a combination of different antioxidants with the addition of vitamins and/or micronutrients) to infertile males. Of these studies, only 33.3% included pregnancy and/or live birth rates as an outcome measure to determine the effects of the therapy. Of these studies, only 4 were case–control studies, and only 2 of them found improvement of the pregnancy rate in the group of antioxidant-treated patients. Additionally, of the 30 studies considered in this review, only 43.3% were case–control studies, 66.7% enrolled a number of patients higher than 40, and 40% carried out the administration of a single antioxidant. Therefore, it appears that further studies are needed to clearly define the usefulness of antioxidant-based therapies to treat male infertility.

Antifungal effect of glow discharge plasma and plasma activated water against brown spot disease of rice

The impact of atmospheric glow discharge plasma and plasma activated water on reducing rice seed-borne brown spot disease was investigated. It has been shown that the generation of reactive oxygen and nitrogen species by plasma containing electrons, positive or negative ions, and neutral species has antimicrobial activity. In this study, four plasmas were used for seed treatment viz., O2-air glow discharge plasma for 90 s, 120 s, air-plasma activated water for 9 and 12 min. Control (without treatment) and chemical treatment were used in order to compare the treatment effect. The plasma treatments used for this study showed a promising positive effect on seed germination and plant growth, and reduction of brown spot severity in the field. Among the plasmas, O2-air glow discharge plasma for 90s significantly increased seed germination (94.67%) compared to control (84.0%). Conidial suspension of Bipolaris oryzae treated with O2-air glow discharge plasma for 90 s and air-plasma activated water for 9 min successfully reduced the conidial germination ability of Bipolaris oryzae on Potato Dextrose Agar (PDA). The brown spot incidence and severity were significantly reduced in the plot which received seed treatment with O2-air glow discharge plasma for 90s and air-plasma activated water for 9 min. Interestingly, the same treatment remarkably enhances the plant growth parameters and yield of BRRI dhan28 compared to control treatment.

Nitric Oxide as a Savior Molecule Against Stress Induced by Chromium and Cadmium

Heavy metals (HMs) pollution is one of soil problems imposing great agronomic challenges leading to obstacles in ascertaining food safety. The deposition of HMs beyond permissible limits due to their uses in various agricultural, industrial and household purposes, greatly affect the soil fertility and physio-biochemical activities of plants growing in such soils. Among HMs, cadmium (Cd) and chromium (Cr) are very toxic, non-essential heavy metals whose concentrations have built-up recently in our environment due to several manmade activities. These elements enter into living organisms either by absorption through plants or are directly consumed by animals or microbes. They induce various morphological and physio-biochemical changes in plants ranging from seed germination, growth, nutrient uptake, photosynthesis to hormonal interactions. Excess reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation are two important markers of nitro-oxidative stress during heavy metal stress. Plants counteract by activating defence responses by inducing expression of antioxidant enzymes like (CAT, SOD, APX) and antioxidant compounds like Vitamin C and GSH. Nitric oxide (NO) is one of the active gaseous molecules generated during nitro-oxidative stress induced by HMs like Cd and Cr. NO is generated in the plants by diverse enzymatic and non-enzymatic systems. The specific and dedicated enzyme system for NO generation is not yet identified in the plants. NO helps to counteract the effects of HMs by activating various biochemical machineries such as induction of antioxidant defence systems, protein nitrosylation, programmed cell death. It is the molecule that has very promising roles and need to be explored much in relation to heavy metals.

Chemical mechanisms of non-thermal plasma action on cells

Non-thermal plasma (NTP) in the air around the cell layer or biological tissues is considered as a generator of reactive oxygen and nitrogen species, ions, and solvated/aquated electrons. This review covers current understanding on the effects of NTP in living systems, with the focus on the role of free radicals and other NTP-generated particles in the chemical modification of biomacromolecules and regulation of signal transduction. We summarise recent data on the impact of NTP-originated products on intracellular redox balance, mitochondrial biogenesis, cell membranes and organelles. In addition, we discuss the transport of NTP products across the biological membranes. Since the expression of numerous transporter systems differs at various stages of development, distinct cell lines, and in pathological conditions, experiments on NTP effects should be designed in various models for the assessment of cell- and tissue-specific response. Notably, NTP effects are observed throughout the whole tissue even when particles are generated at the surface. Special attention is paid to the NTP-treated solutions (phosphate buffered saline, Ringer’s solution, cell culture medium) as their composition and pH can be significantly altered. However, these data also suggest novel opportunities for the application of NTP and NTP-treated solutions in biomedicine. Studies on the mechanisms of NTP action on biological systems should contain analysis of events coupled to generation and accumulation of reactive oxygen and nitrogen species, neutral compounds, solvated electrons, and detection of new cellular targets of their action. This would allow developing of efficient and safe protocols for NTP applications in biology and medicine.

Functional role of iNOS-Rac2 interaction in neutrophil extracellular traps (NETs) induced cytotoxicity in sepsis

BackgroundRecent reports from this lab have demonstrated a higher incidence of NETs, nitrosative, as well as oxidative stress, and have a direct correlation with the severity of sepsis and organ damage. However, the mechanistic perspective of NETs induced organ damage has not been understood at the cellular and molecular level. Interaction of inducible nitric oxide synthase (iNOS) with Rac2 in regulating reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation and its implications in microbial killing has been reported. This study was, therefore, undertaken in neutrophils of sepsis patients to investigate the functional importance of iNOS-Rac2 interaction in ROS/ RNS, peroxynitrite generation, NETs generation, and NETs mediated cell death. MethodsThe study was conducted on 100 patients with sepsis and 50 healthy volunteers. Interaction between iNOS and Rac2 was performed using co-immunoprecipitation and co-immunolabeling assay. Free radicals involving ROS and RNS were evaluated using cytochrome c reduction assay. NETs formation was evaluated by fluorescence microscopy. The cytotoxic effect of NETs was assessed on lung carcinoma cell line (A549) using colorimetric Alamar blue assay. ResultsEnhanced interaction between iNOS and Rac2 was found in sepsis neutrophils in comparison with control. This was accompanied by an increased level of superoxide (O2.−), nitric oxide (NO), and peroxynitrite (ONOO−) which were decreased in the presence of NAC, DPI, and 1400 W, signifying the role of iNOS-Rac2 interaction. Enhanced NETs release from activated sepsis neutrophils were abrogated in the presence of DPI. NETs from sepsis neutrophils exert a cytotoxic effect on lung epithelial cells (A549) in a concentration-dependent manner. ConclusionOur findings exhibit the functional role of iNOS-Rac2 interaction in ROS/RNS, peroxynitrite generation, NETs generation, and NETs mediated cell death.

O6 Evolución temporal de la disfunción mitocondrial cardíaca en diabetes tipo 1

Introducción: hemos demostrado (Bombicino et al., 2016 y 2017) que 25 días de hiperglucemia sostenida conducen a una disfunción mitocondrial cardíaca generalizada que incluye disminución del consumo de O2 tisular y mitocondrial, de las actividades de los complejos I-III, II-III y IV, de la producción de ATP, de la relación ADP/O y de la actividad de Mn-SOD, acompañado de un aumento en las velocidades de producción de H2O2, NO y ONOO-, y al desencadenamiento de biogénesis mitocondrial, aunque las “nuevas” mitocondrias muestran alteraciones estructurales. Dicha disfunción se presenta en ausencia de hipertrofia y de cambios en la función cardíaca en reposo, pero con compromiso cardíaco ante una sobrecarga de trabajo, sugiriendo que la disfunción mitocondrial precede a la falla miocárdica en pacientes diabéticos.Objetivos: estudiar los eventos tempranos y analizar la evolución temporal de la disfunción mitocondrial cardíaca en un modelo de diabetes tipo 1.Materiales y métodos: se indujo diabetes en ratas Wistar macho mediante una dosis de estreptozotocina (STZ, 60 mg/kg, ip). La glucemia se determinó a las 72 h (C:127±5, DM:415±23 mg/dl). Los animales se sacrificaron 7, 10 ó 14 días post-inyección de STZ (4, 7 ó 11 días de hiperglucemia) y se extrajeron los corazones. Se determinó la funcionalidad y biogénesis mitocondrial, la generación de especies reactivas del oxígeno y nitrógeno y el estado redox.

Targeted Antioxidants in Exercise-Induced Mitochondrial Oxidative Stress: Emphasis on DNA Damage.

Exercise simultaneously incites beneficial (e.g., signal) and harming (e.g., damage to macromolecules) effects, likely through the generation of reactive oxygen and nitrogen species (RONS) and downstream changes to redox homeostasis. Given the link between nuclear DNA damage and human longevity/pathology, research attempting to modulate DNA damage and restore redox homeostasis through non-selective pleiotropic antioxidants has yielded mixed results. Furthermore, until recently the role of oxidative modifications to mitochondrial DNA (mtDNA) in the context of exercising humans has largely been ignored. The development of antioxidant compounds which specifically target the mitochondria has unveiled a number of exciting avenues of exploration which allow for more precise discernment of the pathways involved with the generation of RONS and mitochondrial oxidative stress. Thus, the primary function of this review, and indeed its novel feature, is to highlight the potential roles of mitochondria-targeted antioxidants on perturbations to mitochondrial oxidative stress and the implications for exercise, with special focus on mtDNA damage. A brief synopsis of the current literature addressing the sources of mitochondrial superoxide and hydrogen peroxide, and available mitochondria-targeted antioxidants is also discussed.

Fluoride enhances generation of reactive oxygen and nitrogen species, oxidizes hemoglobin, lowers antioxidant power and inhibits transmembrane electron transport in isolated human red blood cells

Fluoride is a widespread environmental pollutant that at high levels exerts numerous deleterious effects on human health. The toxic effects of fluoride are a matter of serious concern since many countries have regions of endemic fluorosis. The main source of fluoride exposure for humans is intake of contaminated groundwater. Fluoride is absorbed from the gastrointestinal tract and enters the circulating blood, where the abundant red blood cells (RBC) are an early and major target of fluoride toxicity. Chronic fluoride exposure generates free radicals, reactive species which leads to redox imbalance, cytotoxicity and hematological damage. This study aimed to determine the effect of sodium fluoride (NaF) on human RBC under in vitro conditions. Isolated RBC were incubated with different concentrations of NaF (10–500 µM) for 8 h at 37 °C. Several biochemical parameters were determined in hemolysates or whole cells. Treatment of RBC with NaF enhanced the generation of reactive oxygen and nitrogen species. This increased the oxidation of hemoglobin to yield methemoglobin and oxoferrylhemoglobin, which are inactive in oxygen transport. NaF treatment increased the degradation of heme causing release of free iron from its porphyrin ring. Cellular antioxidant power was significantly decreased in NaF-treated RBC, lowering the metal reducing and free radical quenching ability of cells. The two pathways of glucose metabolism in RBC i.e. glycolysis and hexose monophosphate shunt, were inhibited. NaF also inhibited the plasma membrane redox system, and its associated ascorbate free radical reductase, to disrupt transmembrane electron transport. These results suggest that fluoride generates reactive species that cause extensive oxidative modifications in human RBC.

Multiple Cryotherapy Attenuates Oxi-Inflammatory Response Following Skeletal Muscle Injury.

The oxi-inflammatory response is part of the natural process mobilizing leukocytes and satellite cells that contribute to clearance and regeneration of damaged muscle tissue. In sports medicine, a number of post-injury recovery strategies, such as whole-body cryotherapy (WBC), are used to improve skeletal muscle regeneration often without scientific evidence of their benefits. The study was designed to assess the impact of WBC on circulating mediators of skeletal muscle regeneration. Twenty elite athletes were randomized to WBC group (3-min exposure to −120 °C, twice a day for 7 days) and control group. Blood samples were collected before the first WBC session and 1 day after the last cryotherapy exposure. WBC did not affect the indirect markers of muscle damage but significantly reduced the generation of reactive oxygen and nitrogen species (H2O2 and NO) as well as the concentrations of serum interleukin 1β (IL-1β) and C-reactive protein (CRP). The changes in circulating growth factors, hepatocyte growth factor (HGF), insulin-like growth factor (IGF-1), platelet-derived growth factor (PDGFBB), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF), were also reduced by WBC exposure. The study demonstrated that WBC attenuates the cascade of injury–repair–regeneration of skeletal muscles whereby it may delay skeletal muscle regeneration.

Nanoparticle-Mediated Radiation-Triggered Release Of Nitrate, Precursor Of Reactive Nitrogen Species, Improves Local Tumor Control

The efficacy of gold nanoparticles (AuNP) as dose-enhancing agents are adversely affected by low tumor uptake, low membrane penetration, and the locality of the AuNP dose enhancement away from relevant targets. To address these limitations, we propose a novel AuNP system for radiation-triggered release of nitrate, a precursor of reactive nitrogen species, and investigate the AuNP efficacy in-vivo. AuNPs were functionalized through PEGylation for increased in vivo circulation time, addition of cell-penetrating peptides (CPP) ([email protected]) for increased membrane penetration, and addition of nitroimidazole (nIm) ([email protected]) to transform local dose enhancement in nitrite release and subsequent generation of reactive nitrogen species that contribute to cell death. NU/NU mice with subcutaneous tumors of the radioresistant breast tumor model 4T1 were injected with either [email protected] or [email protected] via intra-peritoneal injection. Uptake in tumor and normal tissue uptake was assessed at 6 and 24 h after injection. Another cohort of mice was injected and irradiated to a dose of 18 Gy 24h after injection and followed for 2 weeks post irradiation to evaluate tumor response. The mean physical and hydrodynamic size of the nanoparticle systems was 5 and 15 nm, respectively. The addition of nIm on the surface of the nanoparticles did not significantly affect size distribution. A nIm loading of 1 wt% was determined. The tumor accumulation (percent of injected dose per gram (%ID/g)) of [email protected] was significantly lower than the [email protected] accumulation (0.2%ID/g vs 1.2%ID/g). The reverse was seen for normal tissue where [email protected] showed higher accumulation in liver and spleen compared to [email protected] Concerning tumor response, no differential effect was found in un-irradiated mice injected with either saline or [email protected] alone. Furthermore, the combination of [email protected] and radiation had no differential effect from radiation alone. A significant delay in tumor regrowth was observed in the irradiated [email protected] group compared to irradiated controls. The successful synthesis of AuNP functionalized with CPP and nIm showed a significantly increased therapeutic response compared to the same nanoparticle system without nIm. This was observed despite an order of magnitude lower accumulation in tumor tissue. With improved biokinetics, this nanoparticle system would be a promising novel sensitizer of radioresistant and hypoxic tumors.

Dynamic analysis of absorbance behavior and peak shift of RONS in plasma-activated water by UV absorption spectroscopy: dependency on gas impurity, pulse polarity, and solution pH

In this paper, we employ UV absorption spectroscopy to monitor the generation and permeation of reactive oxygen and nitrogen species (RONS) in plasma-activated water (PAW) to revealthe dynamic variation mechanism of RONS chemistry. Parameters including gas impurity, pulse polarity and solution pH value are varied to explore their effects on the absorbance behavior and peak shift of absorption spectra as well as the permeation distribution of RONS. Regarding the absorbance behavior, experimental results show that introducing air and N2 into He working gas would effectively improve RONS absorbance, proportions of about 0.2% air and 0.5% N2 would result in the maximum absorbance, while the addition of O2 would result in a significant decrease in RONS absorbance. Under positive polarity, the RONS absorbance is about 20% higher than that under negative polarity. Changing the solution pH from acidic to alkaline is beneficial in increasing RONS absorbance, indicating that alkaline solution could effectively promote RONS formation. Regarding the characteristic peak shift, different parameter conditions seriously affect the shift of the absorption peak toward low wavelength or high wavelength due to the change in the ratio of the concentration of each component of RONS in PAW. Furthermore, with respect to the permeation distribution of H2O2 and NO2 −, the results show that the addition of O2 would result in the fastest production rate of H2O2 and introducing air and N2 would generate the fastest rate of NO2 − production. Interestingly, the NO2 − permeation distribution displays a ‘columnar mode’ and a ‘filamentous mode’ under positive and negative polarity, respectively. An alkaline solution promotes the formation of NO2 − while having an obvious inhibiting effect on the NO2 − permeation; conversely, an acidic solution has a promotional effect on NO2 −. This study provides a new in-depth understanding of the dynamic evolutionary behavior of RONS in PAW, helping to reveal the network relationship between RONS, and assisting in the development of applications of PAW.

Molecular Species Generated by Surface Dielectric Barrier Discharge Micro-plasma in Small Chambers Enclosing Atmospheric Air and Water Samples

In many applications of the atmospheric pressure plasmas, the plasma is generated in chambers that enclose samples to be treated. In the case of plasma treatments of water or water-containing materials, the humidity in gaseous medium rises during the treatment, and this affects considerably the plasma generation of reactive oxygen and nitrogen species (RONS). In this study, Fourier transform infrared absorption spectroscopy is used to investigate the kinetics of reactive species generated by surface dielectric barrier (SDBD) micro-plasma in a small volume of atmospheric air (0.5 L) enclosed in a discharge chamber. The investigations were made for dry air (in absence of liquid water) and for humid air in presence of liquid water. The SDBD plasma contributes to desorption of water from the inner wall of the discharge chamber and enhances evaporation of liquid water, which increases air humidity and decreases the generation rates of reactive species. Kinetics of RONS generated in small samples of liquid water in contact with discharge medium is investigated by ex situ UV absorption spectroscopy measurements of plasma treated water.

Inactivation of virus and bacteria using cold atmospheric pressure air plasmas and the role of reactive nitrogen species

Cold atmospheric pressure plasma has potential as a non-thermal processing technology to decontaminate food and food contact surfaces due to its ability to generate an abundance of reactive oxygen and nitrogen species with antimicrobial attributes at ambient conditions. In this study, we present a comparison on the effectiveness of surface decontamination against feline calicivirus (FCV) and Salmonella spp using four different plasma sources, a dielectric barrier discharge (DBD) in direct contact with the substrate and three remote plasma treatment sources: a 2D DBD, a volumetric DBD and a gliding arc discharge. The plasma sources were all operated in air at atmospheric pressure. The decontamination efficacy was enhanced by the presence of humidity on the sample surface and only direct contact between plasma and samples allowed the inactivation of pathogens on dry substrates. Across all sources, FCV was seen to be more susceptible to the plasma-generated species than Salmonella spp. The diminished effectiveness of the gliding arc discharge compared to the DBDs operating at the same power is most likely due to the low Henry’s law constant of NO, the dominant reactive species generated by the gliding arc. Control experiments illustrate that the co-existence of O3 and NO2, as in the afterglow of the remote DBDs enhances the inactivation compared to the inactivation by O3 or NO2 only. A chemical kinetics model of the plasma effluent and the plasma treatments show a strong correlation between the gas-phase concentration of N2O5 and inactivation of the virus. We experimentally show that the production of N2O5 coincides with the enhanced generation of reactive nitrogen species in the liquid phase.

Nonthermal Atmospheric Plasma-Induced Cellular Envelope Damage of Staphylococcus aureus and Candida albicans Biofilms: Spectroscopic and Biochemical Investigations

Objective: Nonthermal plasma at atmospheric condition using dielectric barrier discharge (DBD) is reported to be useful in many applications. Here, we have developed a strategy to generate nonthermal atmospheric plasma (NTAP) at ambient conditions for potential biomedical applications. Methods: We have explored the active ingredients of the nonthermal plasma using atomic emission spectroscopy. The potential mechanism of the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) from the generated plasma for therapeutic use has been demonstrated. Major results: The antimicrobial efficacy of the nonthermal plasma application to model Staphylococcus aureus and Candida albicans biofilms has been investigated. Our detailed electron microscopic studies followed by biochemical investigation reveal the mechanism of bacterial/fungal deactivation process. The nuclear magnetic resonance (NMR) studies on the live cell of C . albicans before and after NTAP treatment clearly conclude the disruption of cellular envelope leading to necrosis as evidenced by fluorescence-assisted cell sorting (FACS) studies. Conclusions: The proposed NTAP setup may find relevance in novel strategies in bacterial and fungal biofilm destruction in the future development of nonfluid hand sanitization.

Cold atmospheric plasma induces silver nanoparticle uptake, oxidative dissolution and enhanced cytotoxicity in glioblastoma multiforme cells

Silver nanoparticles (AgNP) emerged as a promising reagent for cancer therapy with oxidative stress implicated in the toxicity. Meanwhile, studies reported cold atmospheric plasma (CAP) generation of reactive oxygen and nitrogen species has selectivity towards cancer cells. Gold nanoparticles display synergistic cytotoxicity when combined with CAP against cancer cells but there is a paucity of information using AgNP, prompting to investigate the combined effects of CAP using dielectric barrier discharge system (voltage of 75 kV, current is 62.5 mA, duty cycle of 7.5kVA and input frequency of 50–60Hz) and 10 nm PVA-coated AgNP using U373MG Glioblastoma Multiforme cells. Cytotoxicity in U373MG cells was >100-fold greater when treated with both CAP and PVA-AgNP compared with either therapy alone (IC50 of 4.30 μg/mL with PVA-AgNP alone compared with 0.07 μg/mL after 25s CAP and 0.01 μg/mL 40s CAP). Combined cytotoxicity was ROS-dependent and was prevented using N-Acetyl Cysteine. A novel darkfield spectral imaging method investigated and quantified AgNP uptake in cells determining significantly enhanced uptake, aggregation and subcellular accumulation following CAP treatment, which was confirmed and quantified using atomic absorption spectroscopy. The results indicate that CAP decreases nanoparticle size, decreases surface charge distribution of AgNP and induces uptake, aggregation and enhanced cytotoxicity in vitro.

Degradation of antibiotic enrofloxacin in water by gas-liquid nsp-DBD plasma: Parametric analysis, effect of H2O2 and CaO2 additives and exploration of degradation mechanisms

Enrofloxacin (ENRO) is a highly toxic fluoroquinolone antibiotic widely used in a broad spectrum of human activities and therefore increased ENRO levels found in aquatic environments pose serious threats for human and livestock health. In this study, a gas–liquid nanosecond pulsed dielectric barrier discharge (nsp-DBD) plasma reactor was used for the degradation of ENRO in aqueous solutions. The increase of pulse peak voltage and the pulse repetition rate, up to a certain limit, were found to enhance ENRO degradation efficiency, degradation rate and energy yield. Under the optimum pulse voltage and pulse frequency, ENRO was completely degraded after 20 min with the corresponding energy yield being 1.1 g/kWh. Air and O2 as working gases displayed superior impact on degradation compared to N2. Additives such as CaO2 and H2O2 were found to enhance the degradation rate with CaO2 being superior promoter compared to H2O2. The UV–Vis emission spectra of the plasma discharge revealed the generation of various reactive nitrogen and oxygen species in the gas phase whereas the concentrations of the reactive gaseous NOx were also measured. In liquid phase, the importance of OH and 1O2 in the degradation process was confirmed by using appropriate scavengers, while H2O2 concentration was quantified by reflectance photometry. A degradation pathway was proposed following HPLC and UPLC/MS analysis of treated samples at various time points of the nsp-DBD treatment. Overall, the complete degradation of enrofloxacin in water was achieved with very high-energy yield suggesting that the current nsp-DBD system could be considered an appealing alternative as a cost-effective technology for the remediation of antibiotic-polluted water systems.