Comparison of free radicals formation induced by cold atmospheric plasma, ultrasound, and ionizing radiation

Multimode ultrasonic-assisted decontamination of fruits and vegetables: A review

Fruits and vegetables (F&V) are a significant part of our diet consumption. Microbial and pesticide residues are the predominant safety hazards of F&V consumption. Ordinary water washing has a very limited effect on removing microorganisms and pesticide residues and requires high water usage. Ultrasound, as an environmentally friendly technology, shows excellent potential for reducing microbial contamination and pesticide residue. This paper summarizes the research on ultrasound application in F&V washing, including the removal of microbial and pesticide residues and the comprehensive effect on their physicochemical characteristics. Furthermore, multimode ultrasonic-assisted techniques like multi-frequency and sequential ultrasound, combined with novel and conventional methods, can enhance the ultrasound-based effect and be more effective and sustainable in preventing F&V from microbial contamination. Overall, this work explicitly establishes the background on the potential for ultrasound cleaning and disinfection in the food industry as a green, effective, and ultimate method of preventing foodborne illnesses.

Effect of AQP4 and its palmitoylation on the permeability of exogenous reactive oxygen species: Insights from computational study

Aquaporin 4 (AQP4) facilitates the transport of reactive oxygen species (ROS). Both cancer cells and the ionizing radiation microenvironment can induce posttranslational modifications (PTMs) in AQP4, which may affect its permeability to ROS. Because this ROS diffusion process is rapid, microscopic, and instantaneous within and outside cells, conventional experimental methods are inadequate for elucidating the molecular mechanisms involved. In this study, computational methods were employed to investigate the permeability of exogenous ROS mediated by radiation in AQP4 at a molecular scale. We constructed a simulation system incorporating AQP4 and AQP4-Cysp13 in a complex lipid environment with ROS. Long-timescale molecular dynamics simulations were conducted to assess the structural stability of both AQP4 and AQP4-Cysp13. Free energy calculations were utilized to determine the ROS transport capability of the two AQP4 proteins. Computational electrophysiology and channel structural analysis quantitatively evaluated changes in ROS transport capacity under various radiation-induced transmembrane voltage microenvironments. Our findings demonstrate the distinct transport capabilities of AQP4 channels for water molecules and various types of ROS and reveal a decrease in transport efficiency when AQP4 undergoes palmitoylation modification. In addition, we have simulated the radiation-induced alteration of cell membrane voltage, which significantly affected the ROS transport capacity. We propose that this research will enhance the understanding of the molecular mechanisms governing the transport of exogenous ROS by AQP4 and elucidate the influence of palmitoylation on ROS transport. This study will also help clarify how different structural features of AQP4 affect the transport of exogenous ROS mediated by radiotherapy, thereby providing a theoretical molecular basis for the development of new treatment strategies that combine with radiotherapy.

Enhanced Antimicrobial Activity through Synergistic Effects of Cold Atmospheric Plasma and Plant Secondary Metabolites: Opportunities and Challenges

The emergence of antibiotic resistant microorganisms possesses a great threat to human health and the environment. Considering the exponential increase in the spread of antibiotic resistant microorganisms, it would be prudent to consider the use of alternative antimicrobial agents or therapies. Only a sustainable, sustained, determined, and coordinated international effort will provide the solutions needed for the future. Plant secondary metabolites show bactericidal and bacteriostatic activity similar to that of conventional antibiotics. However, to effectively eliminate infection, secondary metabolites may need to be activated by heat treatment or combined with other therapies. Cold atmospheric plasma therapy is yet another novel approach that has proven antimicrobial effects. In this review, we explore the physiochemical mechanisms that may give rise to the improved antimicrobial activity of secondary metabolites when combined with cold atmospheric plasma therapy.

Low-Temperature Plasma-Activated Medium Inhibits the Migration of Non-Small Cell Lung Cancer Cells via the Wnt/β-Catenin Pathway

This study explored the molecular mechanism of the plasma activation medium (PAM) inhibiting the migration ability of NSCLC (non-small cell lung cancer) cells. The effect of PAM incubation on the cell viability of NSCLC was detected through a cell viability experiment. Transwell cells and microfluidic chips were used to investigate the effects of PAM on the migration capacity of NSCLC cells, and the latter was used for the first time to observe the changes in the migration capacity of cancer cells treated with PAM. Moreover, the molecular mechanisms of PAM affecting the migration ability of NSCLC cells were investigated through intracellular and extracellular ROS detection, mitochondrial membrane potential, and Western blot experiments. The results showed that after long-term treatment with PAM, the high level of ROS produced by PAM reduced the level of the mitochondrial membrane potential of cells and blocked the cell division cycle in the G2/M phase. At the same time, the EMT process was reversed by inhibiting the Wnt/β-catenin signaling pathway. These results suggested that the high ROS levels generated by the PAM treatment reversed the EMT process by inhibiting the WNT/β-catenin pathway in NSCLC cells and thus inhibited the migration of NSCLC cells. Therefore, these results provide good theoretical support for the clinical treatment of NSCLC with PAM.

Evaluation of cold atmospheric pressure plasma irradiation of water as a method of singlet oxygen generation

We used cold atmospheric pressure plasma jet to examine in detail 1O2 generation in water. ESR with 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide, a secondary amine probe, was used for the detection of 1O2. Nitroxide radical formation was detected after cold atmospheric pressure plasma jet irradiation of a 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide solution. An 1O2 scavenger/quencher inhibited the ESR signal intensity induced by cold atmospheric pressure plasma jet irradiation, but this inhibition was not 100%. As 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide reacts with oxidizing species other than 1O2, it was assumed that the signal intensity inhibited by NaN3 corresponds to only the nitroxide radical generated by 1O2. The concentration of 1O2 produced by cold atmospheric pressure plasma jet irradiation for 60 s was estimated at 8 μM. When this 1O2 generation was compared to methods of 1O2 generation like rose bengal photoirradiation and 4-methyl-1,4-etheno-2,3-benzodioxin-1(4H)-propanoic acid (endoperoxide) thermal decomposition, 1O2 generation was found to be, in decreasing order, rose bengal photoirradiation ≥ cold atmospheric pressure plasma jet > endoperoxide thermal decomposition. Cold atmospheric pressure plasma jet is presumed to not specifically generate 1O2, but can be used to mimic states of oxidative stress involving multiple ROS.

Saponarin, a Di-glycosyl Flavone from Barley (Hordeum vulgare L.): An Effective Compound for Plant Defense and Therapeutic Application

Saponarin (SA) is a major di-C-glycosyl-O-glycosyl flavone, which is predominantly accumulated in the young green leaves of barley (Hordeum vulgare L.), with numerous biological functions in plants, such as protection against environmental stresses. Generally, SA synthesis and its localization in the mesophyll vacuole or leaf epidermis are largely stimulated in response to biotic and abiotic stresses to participate in a plant's defense response. In addition, SA is also credited for its pharmacological properties, such as the regulation of signaling pathways associated with antioxidant and anti-inflammatory responses. In recent years, many researchers have shown the potential of SA to treat oxidative and inflammatory disorders, such as in protection against liver diseases, and reducing blood glucose, along with antiobesity effects. This review aims to highlight natural variations of SA in plants, biosynthesis pathway, and SA's role in response to environmental stress and implications in various therapeutic applications. In addition, we also discuss the challenges and knowledge gaps concerning SA use and commercialization.

Impact of Fermentation Conditions on Physicochemical Properties, Antioxidant Activity, and Sensory Properties of Apple-Tomato Pulp

The aim of the study was to optimize the conditions [inoculum size (4, 6, and 8%), fermentation temperature (31, 34, and 37 °C), and apple: tomato ratio (2:1, 1:1, and 1:2)] on the viable cell count and sensory evaluation in apple-tomato pulp by response surface methodology (RSM), and determine the physicochemical properties, antioxidant activity, and sensory properties during fermentation. The optimal treatment parameters obtained were an inoculum size of 6.5%, a temperature of 34.5 °C, and an apple: tomato ratio of 1:1. After fermentation, the viable cell count reached 9.02 lg(CFU/mL), and the sensory evaluation score was 32.50. During the fermentation period, the pH value, total sugar, and reducing sugar decreased by 16.67%, 17.15%, and 36.05%, respectively. However, the total titratable acid (TTA), viable cell count, total phenol content (TPC), and total flavone content (TFC) increased significantly by 13.64%, 9.04%, 21.28%, and 22.22%, respectively. The antioxidant activity [2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging ability, 2,2'-azino-di(2-ethyl-benzthiazoline-sulfonic acid-6) ammonium salt (ABTS) free-radical scavenging ability, and ferric-reducing antioxidant capacity power (FRAP)] also increased by 40.91%, 22.60%, and 3.65%, respectively, during fermentation. A total of 55 volatile flavour compounds were detected using HS-SPME-GC-MS among the uninoculated samples and fermented samples before and after fermentation. The results showed that fermentation increased the types and total amount of volatile components in apple-tomato pulp, and eight new alcohols and seven new esters were formed. Alcohols, esters, and acids were the main volatile components in apple-tomato pulp, accounting for 57.39%, 10.27%, and 7.40% of the total volatile substances, respectively.

Effect of cold plasma on breaking activated sludge and the output dominance of protein

Upon contacting with water, cold plasma should produce numerous ozone molecules and free electrons at room temperature. In this study, a cold plasma generator was used to break the walls of residual activated sludge obtained from domestic sewage. The impact was mainly influenced by the ozone generated. With 800 W power, sludge wastewater pH of 12.0, and under continuous treatment for 10 h, the system's reduction efficiency for the dry sludge was ≈90%. Furthermore, the organic matter content (especially protein) of the upper layer of the sludge solution increased a lot after the sludge digestion. This observation proved the reduction of sludge from both sides. Moreover, when the cold plasma technique was compared with thermal acid hydrolysis, thermal alkali hydrolysis, and ultrasonication for extracting protein from activated sludge, cold plasma wall-breaking sludge exhibited the highest efficiency, reaching 38.2% under ambient temperature. After the analysis, the toxic metal content in the extracted protein was near zero, which is a level other protein extraction methods via sludge breaking have not achieved to date, we attribute this efficiency to free electrons the cold plasma produce. These species promote the transformation of metal ions into atomic metals, thereby facilitating their removal.

Some Beneficial Effects of Inert Gases on Blood Oxidative Metabolism: In Vivo Study

The aim of the study was to assess the effect of external use of inert gases (helium and argon) on the state of free radical processes in vivo. The experiment was performed on 30 male Wistar stock rats (age-3 months, weight-200-220 g.), randomly distributed into 3 equal groups. The first group of animals was intact (n = 10). The animals of the second and third groups were treated with argon and helium streams, respectively. Our research has allowed us to establish that the studied inert gases have a modulating effect on the state of oxidative metabolism of rat blood, and the nature of this effect is directly determined by the type of gas. The results of this study allowed us to establish the potential antioxidant effect of the helium stream, mainly realized due to the activation of the catalytic properties of the enzymatic link of the antioxidant system of rat blood plasma. At the same time, the revealed features of shifts in oxidative metabolism during treatment with argon flow include not only stimulation of the antioxidant system but also the pronounced induction of free radical oxidation. Thus, the conducted studies made it possible to verify the specificity of the response of the oxidative metabolism of blood plasma to the use of inert gases, depending on their type.

Emerging innovations in cold plasma therapy against cancer: A paradigm shift

Cancer is one of the major causes of mortality, accounting for ∼ 9.5 million deaths globally in 2018. The spectrum of conventional treatment for cancer includes surgery, chemotherapy and radiotherapy. Recently, cold plasma therapy surfaced as a novel technique in the treatment of cancer. The FDA approval of the first trial for the use of cold atmospheric plasma (CAP) in cancer therapy in 2019 is evidence of this. This review highlights the mechanisms of action of CAP. Additionally, its applications in anticancer therapy have been reviewed. In summary, this article will introduce the readers to the exciting field of plasma oncology and help them understand the current status and prospects of plasma oncology.

Enhanced solar inactivation of fungal spores by addition of low-dose chlorine: Efficiency and mechanism

This work demonstrated that the solar inactivation of fungal spores was enhanced by addition of low-dose chlorine. Although the effect of low-dose chlorine alone (2.0 mg/L) on culturability of fungal spores was negligible, the solar/chlorine inactivation on fungal spores performed better than solar alone inactivation, with a lower shoulder length and a higher maximum inactivation rate constant. The enhanced inactivation of Aspergillus niger can be ascribed to the membrane oxidation by chlorine, and the enhanced inactivation of Penicillium polonicum can be ascribed to the membrane oxidation by chlorine and ·OH (·OH plays a major role). The oxidization by chlorine and ·OH led to an increase in membrane permeability of fungal spores, which enhanced the solar inactivation, resulting in an increase in intracellular ROS and more serious morphological damage. Due to the presence of background substances such as dissolved organic matter and metal ions (Fe²⁺, Mn²⁺, etc.), the inactivation efficiency in real water matrices was decreased. The main disinfection by-products (DBPs) produced in the inactivation of fungal spores in chlorine alone and solar/chlorine treatments were dichloroacetic acid, trichloroacetic acid, trichloroacetone and trichloromethane. Generally, DBPs formation in solar/chlorine treatment was lower than those in chlorine alone treatment. Moreover, the regrowth potential of the two genera of fungal spores in R2A medium could be inhibited by adding low-dose chlorine.

Cold Argon Athmospheric Plasma for Biomedicine: Biological Effects, Applications and Possibilities

Currently, plasma medicine is a synthetic direction that unites the efforts of specialists of various profiles. For the successful formation of plasma medicine, it is necessary to solve a large complex of problems, including creating equipment for generating cold plasma, revealing the biological effects of this effect, as well as identifying and justifying the most promising areas of its application. It is known that these biological effects include antibacterial and antiviral activity, the ability to stimulate hemocoagulation, pro-regenerative properties, etc. The possibility of using the factor in tissue engineering and implantology is also shown. Based on this, the purpose of this review was to form a unified understanding of the biological effects and biomedical applications of argon cold plasma. The review shows that cold plasma, like any other physical and chemical factors, has dose dependence, and the variable parameter in this case is the exposure of its application. One of the significant characteristics determining the specificity of the cold plasma effect is the carrier gas selection. This gas carrier is not just an ionized medium but modulates the response of biosystems to it. Finally, the perception of cold plasma by cellular structures can be carried out by activating a special molecular biosensor, the functioning of which significantly depends on the parameters of the medium (in the field of plasma generation and the cell itself). Further research in this area can open up new prospects for the effective use of cold plasma.

Therapeutic Effects of Cold Atmospheric Plasma on Solid Tumor

Cancer is a devastating disease, and there is no particularly effective treatment at present. Recently, a new treatment, cold atmospheric plasma (CAP), has been proposed. At present, CAP is confirmed to have selective killing effect on tumor by many studies in vitro and in vivo. A targeted literature search was carried out on the study of cold atmospheric plasma. Through analysis and screening, a narrative review approach was selected to describe therapeutic effects of cold atmospheric plasma on solid tumor. According to the recent studies on plasma, some hypothetical therapeutic schemes of CAP are proposed in this paper. The killing mechanism of CAP on solid tumor is expounded in terms of the selectivity of CAP to tumor, the effects of CAP on cells, tumor microenvironment (TME) and immune system. CAP has many effects on solid tumors, and these effects are dose-dependent. The effects of optimal doses of CAP on solid tumors include killing tumor cells, inhibiting non-malignant cells and ECM in TME, affecting the communication between tumor cells, and inducing immunogenic death of tumor cells. In addition, several promising research directions of CAP are proposed in this review, which provide guidance for future research.

Kinetic modelling of ultrasound-assisted extraction of phenolics from cereal brans

Cereal brans are by-products of the milling of cereal grains, which are mainly used as low value ingredients in animal feed. Wheat and oat bran is a rich source of bioactives and phytochemicals, especially phenolic compounds. Within this study, the application of ultrasound (US) technology to assist the extraction of phenolics from oat and wheat bran was investigated (20-45 kHz). Peleg's mathematical model was used to study the kinetics of ultrasound-assisted extraction (UAE) and subsequent stirring of total phenolic compounds (TPC). The surface morphology of cereal brans after extraction was studied using SEM analysis. The excellent agreement was determined between the values of TPC calculated from Peleg's mathematical model and actual experimental results. The constant that represents a time required for the initial phenolic concentration to be extracted to one-half of its initial value has been introduced (K_1/2). It was shown that the TPC extraction kinetics was dependent only on K_1/2 enabling fast kinetics fitting and comparison between extraction rates. Moreover, different values of K_1/2 constant could indicate the differences in brans composition and consequently different influence of US pretreatment on these samples.

Reactive oxygen species (ROS): utilizing injectable antioxidative hydrogels and ROS-producing therapies to manage the double-edged sword

Reactive oxygen species (ROS) are generated in cellular metabolism and are essential for cellular signalling networks and physiological functions. However, the functions of ROS are 'double-edged swords' to living systems that have a fragile redox balance between ROS generation and elimination. A modest increase of ROS leads to enhanced cell proliferation, survival and benign immune responses, whereas ROS stress that overwhelms the cellular antioxidant capacity can damage nucleic acids, proteins and lipids, resulting in oncogenic mutations and cell death. ROS are therefore involved in many pathological conditions. On the other hand, ROS present selective toxicity and have been utilised against cancer and pathogens, thus also acting as a double-edged sword in the healthcare field. Injectable antioxidative hydrogels are gel precursors that form hydrogel constructs in situ upon delivery in vivo to maintain an antioxidative capacity. These hydrogels have been developed to counter ROS-induced pathological conditions, with significant advantages of biocompatibility, excellent moldability, and minimally invasive delivery. The intrinsic, readily controllable ROS-scavenging ability of the functionalised hydrogels overcomes many drawbacks of small molecule antioxidants. This review summarises the roles of ROS under pathological conditions and describes the state-of-the-art of injectable antioxidative hydrogels. A particular emphasis is also given to current ROS-producing therapeutic interventions, enabling potential application of injectable antioxidant hydrogels to prevent the adverse effects of many cancer and infection treatments.

Non-Thermal Atmospheric Pressure Argon-Sourced Plasma Flux Promotes Wound Healing of Burn Wounds and Burn Wounds with Infection in Mice through the Anti-Inflammatory Macrophages

Plasma medicine is the utilization of gas ionization that might be beneficial for the treatment of burn wounds, a healthcare problem with a significant mortality rate. Due to a lack of information on the impact of plasma flux in immune cells and a high prevalence of bacterial infection in burn wounds, non-thermal argon-based plasma flux was tested on macrophages (RAW246.7) and in mouse models of burn wounds with or without Staphylococcus aureus infection. Accordingly, plasma flux enhanced reactive oxygen species (ROS), using dihydroethidium assay, and decreased abundance of NF-κB-p65 (Western blot analysis) in non-stimulating macrophages. In parallel, plasma flux upregulated IL-10 gene expression (an anti-inflammatory cytokine) in lipopolysaccharide (LPS)-induced inflammatory macrophages, while downregulating the pro-inflammatory cytokines (IL-1β and IL-6). Additionally, plasma flux improved the migratory function of fibroblasts (L929) (fibroblast scratch assay) but not fibroblast proliferation. Moreover, once daily plasma flux administration for 7 days promoted the healing process in burn wounds with or without infection (wound area and wound rank score). Additionally, plasma flux reduced tissue cytokines (TNF-α and IL-6) in burn wounds with infection and promoted collagen in burn wounds without infection. In conclusion, plasma flux induced anti-inflammatory macrophages and promoted the burn-wound healing process partly through the decrease in macrophage NF-κB. Hence, plasma flux treatment should be tested in patients with burn wounds.

The cold eye irrigation BSS solution used during phacoemulsification reduces post-surgery patients discomfort preventing the inflammation

PURPOSE

The aim of this study was to assess whether the intraoperative use of the cold eye irrigation balanced salt solution (BSS) could have a protective effect in preventing the anterior chamber flare and conjunctival hyperemia and, thus, in reducing patients discomfort after phacoemulsification.

MATERIALS AND METHODS

About 214 patients were enrolled and randomly divided into: patients whose eye were irrigated with BSS at ~ 20°C (Group 1) and patients whose eye were irrigated with BSS at 2.7°C (Group 2). Anterior chamber flare, visual analogue score and conjunctival hyperemia were evaluated at 1, 3, 5, and 30 days after surgery.

RESULTS

In patients of Group 2 the anterior chamber flare, the visual analogue score and the conjunctival hyperemia, used as parameters to evaluated clinical inflammation, at 1 day after surgery were significantly lower than those in Group 1 who received BSS solution at operating room temperature (p < 0.001), while at day 3, 5, and 30 there were not any significant differences.

CONCLUSION

Our study provided evidence supporting the efficacy of the treatment with cold irrigation solution on reduction of anterior chamber flare, pain and conjunctival hyperemia already at 1 day after phacoemulsification, suggesting that cooling procedure was fully effective at controlling early post-operative inflammation.

Carcinogenesis as Side Effects of Iron and Oxygen Utilization: From the Unveiled Truth toward Ultimate Bioengineering

Simple Summary

Cancer is a major cause of human mortality worldwide. No life on earth can live without iron. Persistent oxidative stress resulting from continuous use of iron and oxygen may be a fundamental cause of carcinogenesis. Many animal models demonstrated that excess iron may lead to carcinogenesis. This is supported by a variety of human epidemiological data on cancer risk and prognosis. Cancer is basically a disease of the genome with persistently activated oncogenes and inactivated tumor suppressor genes through which iron addiction with ferroptosis-resistance is established. We predict that fine use of nanomaterials and non-thermal plasma may be able to reverse this situation.

Abstract

Evolution from the first life on earth to humans took ~3.8 billion years. During the time there have been countless struggles among the species. Mycobacterium tuberculosis was the last major uncontrollable species against the human public health worldwide. After the victory with antibiotics, cancer has become the leading cause of death since 1981 in Japan. Considering that life inevitably depends on ceaseless electron transfers through iron and oxygen, we believe that carcinogenesis is intrinsically unavoidable side effects of using iron and oxygen. Many animal models unequivocally revealed that excess iron is a risk for carcinogenesis. This is supported by a variety of human epidemiological data on cancer risk and prognosis. Cancer is basically a disease of the genome with persistently activated oncogenes and inactivated tumor suppressor genes through which iron addiction with ferroptosis-resistance is maintained. Engineering has made a great advance in the past 50 years. In particular, nanotechnology is distinct in that the size of the engineered molecules is similar to that of our biomolecules. While some nano-molecules are found carcinogenic, there are principles to avoid such carcinogenicity with a smart possibility to use nano-molecules to specifically kill cancer cells. Non-thermal plasma is another modality to fight against cancer.

Cold Atmospheric Pressure Plasma (CAP) as a New Tool for the Management of Vulva Cancer and Vulvar Premalignant Lesions in Gynaecological Oncology

Vulvar cancer (VC) is a specific form of malignancy accounting for 5–6% of all gynaecologic malignancies. Although VC occurs most commonly in women after 60 years of age, disease incidence has risen progressively in premenopausal women in recent decades. VC demonstrates particular features requiring well-adapted therapeutic approaches to avoid potential treatment-related complications. Significant improvements in disease-free survival and overall survival rates for patients diagnosed with post-stage I disease have been achieved by implementing a combination therapy consisting of radical surgical resection, systemic chemotherapy and/or radiotherapy. Achieving local control remains challenging. However, mostly due to specific anatomical conditions, the need for comprehensive surgical reconstruction and frequent post-operative healing complications. Novel therapeutic tools better adapted to VC particularities are essential for improving individual outcomes. To this end, cold atmospheric plasma (CAP) treatment is a promising option for VC, and is particularly appropriate for the local treatment of dysplastic lesions, early intraepithelial cancer, and invasive tumours. In addition, CAP also helps reduce inflammatory complications and improve wound healing. The application of CAP may realise either directly or indirectly utilising nanoparticle technologies. CAP has demonstrated remarkable treatment benefits for several malignant conditions, and has created new medical fields, such as “plasma medicine” and “plasma oncology”. This article highlights the benefits of CAP for the treatment of VC, VC pre-stages, and postsurgical wound complications. There has not yet been a published report of CAP on vulvar cancer cells, and so this review summarises the progress made in gynaecological oncology and in other cancers, and promotes an important, understudied area for future research. The paradigm shift from reactive to predictive, preventive and personalised medical approaches in overall VC management is also considered.

Small size gold nanoparticles enhance apoptosis-induced by cold atmospheric plasma via depletion of intracellular GSH and modification of oxidative stress

Gold nanoparticles (Au-NPs) have attracted attention as a promising sensitizer owing to their high atomic number (Z), and because they are considered fully multifunctional, they are preferred over other metal nanoparticles. Cold atmospheric plasma (CAP) has also recently gained attention, especially for cancer treatment, by inducing apoptosis through the formation of reactive oxygen species (ROS). In this study, the activity of different sized Au-NPs with helium-based CAP (He-CAP) was analyzed, and the underlying mechanism was investigated. Treating cells with only small Au-NPs (2 nm) significantly enhanced He-CAP-induced apoptosis. In comparison, 40 nm and 100 nm Au-NPs failed to enhance cell death. Mechanistically, the synergistic enhancement was due to 2 nm Au-NPs-induced decrease in intracellular glutathione, which led to the generation of intracellular ROS. He-CAP markedly induced ROS generation in an aqueous medium; however, treatment with He-CAP alone did not induce intracellular ROS formation. In contrast, the combined treatment significantly enhanced the intracellular formation of superoxide (O2• -) and hydroxyl radical (•OH). These findings indicate the potential therapeutic use of Au-NPs in combination with CAP and further clarify the role of Au-NPs in He-CAP-aided therapies.

Direct EPR detection of atomic nitrogen in an atmospheric nitrogen plasma jet

In this study, an atmospheric nitrogen plasma jet generated by a custom-built micro-plasma device was analyzed at room temperature by continuous wave and pulse EPR spectroscopy in real time. Transiently formed nitrogen atoms were detected without the necessity to use spin-traps or other reagents for their stabilization. In contrast to results from optical emission spectroscopy, only signals from the ⁴S ground state of ¹⁴N and ¹⁵N could be detected. EPR data analysis revealed an isotropic g value of 1.9971 and isotropic hyperfine coupling constants of a(¹⁴N) = (10.47 ± 0.02) MHz and a(¹⁵N) = (14.69 ± 0.02) MHz. Moreover, lifetime and relaxation data could be determined; both are discussed in terms of spectral widths and actual concentrations of the transiently formed nitrogen species within the plasma jet. The data show that the lifetimes of atomic nitrogen and charged particles such as N⁺ must be different, and for the latter below the observation time window of EPR spectroscopy. We demonstrate that the real-time (pulsed) EPR technique is a fast and reliable alternative to detect atomic nitrogen in atmospheric pressure plasma jets. The method may be used for a continuous monitoring of the quality of plasma jets.

Combination of Gas Plasma and Radiotherapy Has Immunostimulatory Potential and Additive Toxicity in Murine Melanoma Cells in Vitro

Despite continuous advances in therapy, malignant melanoma is still among the deadliest types of cancer. At the same time, owing to its high plasticity and immunogenicity, melanoma is regarded as a model tumor entity when testing new treatment approaches. Cold physical plasma is a novel anticancer tool that utilizes a plethora of reactive oxygen species (ROS) being deposited on the target cells and tissues. To test whether plasma treatment would enhance the toxicity of an established antitumor therapy, ionizing radiation, we combined both physical treatment modalities targeting B16F10 murine melanoma cell in vitro. Repeated rather than single radiotherapy, in combination with gas plasma-introduced ROS, induced apoptosis and cell cycle arrest in an additive fashion. In tendency, gas plasma treatment sensitized the cells to subsequent radiotherapy rather than the other way around. This was concomitant with increased levels of TNFα, IL6, and GM-CSF in supernatants. Murine JAWS dendritic cells cultured in these supernatants showed an increased expression of cell surface activation markers, such as MHCII and CD83. For PD-L1 and PD-L2, increased expression was observed. Our results are the first to suggest an additive therapeutic effect of gas plasma and radiotherapy, and translational tumor models are needed to develop this concept further.

Chemical-free and synergistic interaction of ultrasound combined with plasma-activated water (PAW) to enhance microbial inactivation in chicken meat and skin

In general, the poultry industry uses 0.5–1 ppm chlorine solution in the meat sanitization process. However, chlorine can react with organic material and produce halogenated organic compounds, notably chloroform, which causes bladder and rectal cancer in humans. For this reason, many industries try to avoid chlorine. This study investigated the efficacy of ultrasound and plasma-activated water (PAW) on the inactivation of Escherichia coli and Staphylococcus aureus in chicken muscle, rough skin, and smooth skin. Samples inoculated with bacteria suspension were treated by ultrasound alone and PAW–ultrasound. The Taguchi method and desirability function approach were used for the experimental design and optimization. Combined ultrasound and PAW inactivated up to 1.33 log CFU/ml of E. coli K12 and 0.83 log CFU/ml of S. aureus at a sample thickness of 4 mm, at 40 °C for 60 min, while PAW alone only reduced E. coli K12 by 0.46 log CFU/ml and S. aureus by 0.33 log CFU/ml under the same condition. The muscle topography showed a porous structure, which facilitated the penetration of PAW. The color measurements of muscle treated with ultrasound and PAW–ultrasound were dramatically different from the untreated sample, as also perceived by the sensory evaluation panel. Therefore, the synergistic interaction of combined PAW–ultrasound could be used to enhance microbial inactivation in meat.

Antibacterial efficacy of cold atmospheric plasma against Enterococcus faecalis planktonic cultures and biofilms in vitro

Nosocomial infections have become a serious threat in our times and are getting more difficult to handle due to increasing development of resistances in bacteria. In this light, cold atmospheric plasma (CAP), which is known to effectively inactivate microorganisms, may be a promising alternative for application in the fields of dentistry and dermatology. CAPs are partly ionised gases, which operate at low temperature and are composed of electrons, ions, excited atoms and molecules, reactive oxygen and nitrogen species. In this study, the effect of CAP generated from ambient air was investigated against Enterococcus faecalis, grown on agar plates or as biofilms cultured for up to 72 h. CAP reduced the colony forming units (CFU) on agar plates by > 7 log₁₀ steps. Treatment of 24 h old biofilms of E. faecalis resulted in CFU-reductions by ≥ 3 log₁₀ steps after CAP treatment for 5 min and by ≥ 5 log₁₀ steps after CAP treatment for 10 min. In biofilm experiments, chlorhexidine (CHX) and UVC radiation served as positive controls and were only slightly more effective than CAP. There was no damage of cytoplasmic membranes upon CAP treatment as shown by spectrometric measurements for release of nucleic acids. Thus, membrane damage seems not to be the primary mechanism of action for CAP towards E. faecalis. Overall, CAP showed pronounced antimicrobial efficacy against E. faecalis on agar plates as well as in biofilms similar to positive controls CHX or UVC.

Biological and medical applications of plasma-activated media, water and solutions

Non-thermal atmospheric pressure plasma has been proposed as a new tool for various biological and medical applications. Plasma in close proximity to cell culture media or water creates reactive oxygen and nitrogen species containing solutions known as plasma-activated media (PAM) or plasma-activated water (PAW) - the latter even displays acidification. These plasma-treated solutions remain stable for several days with respect to the storage temperature. Recently, PAM and PAW have been widely studied for many biomedical applications. Here, we reviewed promising reports demonstrating plasma-liquid interaction chemistry and the application of PAM or PAW as an anti-cancer, anti-metastatic, antimicrobial, regenerative medicine for blood coagulation and even as a dental treatment agent. We also discuss the role of PAM on cancer initiation cells (spheroids or cancer stem cells), on the epithelial mesenchymal transition (EMT), and when used for metastasis inhibition considering its anticancer effects. The roles of PAW in controlling plant disease, seed decontamination, seed germination and plant growth are also considered in this review. Finally, we emphasize the future prospects of PAM, PAW or plasma-activated solutions in biomedical applications with a discussion of the mechanisms and the stability and safety issues in relation to humans.

[Cold atmospheric plasma for the treatment of urological tumors]

Cold atmospheric plasma (CAP) is a highly reactive ionized physical state consisting of electrically charged particles, radicals and photons as well as electromagnetic radiation. Due to the high energy and reactivity of plasma components, physical plasmas are also referred to as the 4th aggregate state. In biological systems, CAP promotes antimicrobial, immunomodulatory, anti-inflammatory, and wound-healing effects. Moreover, CAP bears antineoplastic properties which may be applied as a potential intraoperative option in the treatment of wound and resection margins during surgery of urological tumors. Some properties such as the penetration depth in various biological tissues, the effect on physiological healthy tissue, and the molecular mode of action regarding signalling and effector pathways are the subject of further investigation. CAP treatment effectively attenuates malignant cell growth. As an intraoperative application, CAP may represent a promising option particularly for the treatment of tissue regions that are close to critical structures (e. g., nerves, adjacent organs). The present review article summarizes the current status of CAP-related studies in the field of urological oncology.

Differential response of immortalized human amnion mesenchymal and epithelial cells against oxidative stress

Cells are equipped with various antioxidant defense factors to antagonize insults from reactive oxygen species (ROS), thus the antioxidant capacity has been characterized by a variety of cellular responses during the pathophysiological processes. Amniotic cells have been extensively applied in clinical practice for burn treatment, corneal repair, and tissue regeneration. However, the antioxidative properties of amniotic cells have not yet been fully understood. Therefore, the current study was aimed to observe the response of amniotic cells against ROS stimuli, and to investigate the underlying molecular mechanisms. The immortalized human amniotic mesenchymal cells (iHAMs) and immortalized human amniotic epithelial cells (iHAEs) were used. The human skin fibroblast (HSF) was used as a control cell line. Changes in intracellular ROS generation, cell viability, and cellular morphology were investigated to reveal the response of amniotic cells against oxidative stresses induced by x-rays and hydrogen peroxide. In addition, expression of apoptosis-related proteins and response to antioxidative stress was also examined. The intracellular ROS level and cell apoptosis in iHAMs was remarkably increased. iHAEs showed relatively high resistance to ROS stimulation, which can be attributed to the high SOD2 expression and up-regulation of Nrf2, HO-1 after x-rays exposure. In contrast, iHAMs were found sensitive to oxidative damage. Expression of caspase-3, caspase-8 and BAX was increased, whereas down-regulation of Bcl-xL, Nrf2, HO-1, and TrxR-1. Taken together, findings have highlighted the characterization of response of amniotic derived epithelial and mesenchymal cells to oxidative stress. In physiological processes, iHAMs may play an important role to maintain the homeostasis of the pregnancy environment. However, under oxidative stimulations, iHAEs provides protection against oxidative damage in amnion tissue.

Total yield of reactive species originating from an atmospheric pressure plasma jet in real time

It is now well established that plasma-induced reactive species are key agents involved in many biochemical reactions. This work reports on the formation of plasma reactive species in an acidified ferrous sulfate (Fricke) solution interacting with an atmospheric pressure plasma jet (APPJ). A yield of ferric (Fe3+) ions measured using in situ absorption spectroscopy was attributed to the formation of plasma reactive species provided and/or originated in the solution. The results indicated that the number of reactive species formed was proportional to plasma frequency and voltage. However, the Fe3+ yield per pulse decreased with increased frequency. To obtain a better understanding of the processes and species involved in the chemical reactions due to plasma exposure, Fe3+ yields were calculated and compared to the experimental data. At higher frequencies, there was insufficient time to complete all the reactions before the next pulse reached the solution; at lower frequencies, the Fe3+ yield was higher because of the relatively longer time available for reactions to occur. In addition, the comparison between DNA damage levels and Fe3+ yields was investigated under different experimental conditions in order to verify the usefulness of both the Fricke solution and the DNA molecule as a probe to characterize APPJs.

Sono-activated persulfate oxidation of diclofenac: Degradation, kinetics, pathway and contribution of the different radicals involved

Degradation of a diclofenac aqueous solution was performed using persulfate anions activated by ultrasound. The objective of this study was to analyze different parameters affecting the diclofenac (DCF) removal reaction by the ultrasonic persulfate (US/PS) process and to evaluate the role played by various intermediate oxidative species such as hydroxyl- and sulfate radicals, superoxide radical anion or singlet oxygen in the removal process as well as to determine a possible reaction pathway. The effects of pH, initial persulfate anion concentration, ultrasonic amplitude and temperature on DCF degradation were examined. Sulfate and hydroxyl radicals were involved in the main reaction pathway of diclofenac. Diclofenac amide and three hydroxy-diclofenac isomers (3´-hydroxy diclofenac, 4´-hydroxy diclofenac and 5-hydroxy diclofenac) were identified as reaction intermediates.

Influences of cold atmospheric plasma on microbial safety, physicochemical and sensorial qualities of meat products

Meat and meat products can be contaminated with pathogenic microorganisms, which cause serious health problems and economic loss. Recently, numerous novel non-thermal technologies have been developed to respond to growing consumer demand for high quality and safe meat products. Cold atmospheric plasma (CAP) is a novel and emerging non-thermal technology, showing great potential for applications in the food industry. This review presents recent advances on the developments and applications of CAP in meat products, including generation and microbial inactivation effects of CAP as well as its influences on physicochemical qualities and sensory attributes of meat products. Furthermore, the safety assessment of CAP-treated meat products and challenges in industrial application of CAP are also discussed.

Inactivation of soybean trypsin inhibitor by dielectric-barrier discharge (DBD) plasma

Soybean trypsin inhibitor (STI) is considered as one of the most important anti-nutritional factors in soybeans. The objective of this study was to investigate the impacts and underling mechanisms of dielectric-barrier discharge (DBD) plasma on STI activities. The results shown that DBD plasma treatment significantly induced the inactivation of STI in soymilk and Kunitz-type trypsin inhibitor from soybean (SKTI) in a model system. After exposure to DBD plasma at 51.4W for 21min, the STI activities of soymilk were reduced by 86.1%. Affter being treated by DBD plasma, the intrinsic fluorescence and surface hydrophobicity of SKTI were significantly decreased, while the sulfhydryl contents were increased. It is assumed that DBD plasma-induced conformational changes and oxidative modification might contribute to the inactivation of SKTI. In summary, DBD plasma technology is a potential alternative to heat treatment for the inactivation of anti-nutritional substances in food legumes.

In vitro Demonstration of Cancer Inhibiting Properties from Stratified Self-Organized Plasma-Liquid Interface

Experiments on plasma-liquid interaction and formation of thinly stratified self-organized patterns at plasma-liquid interface have revealed a nontrivial cancer-inhibiting capability of liquid media treated at self-organized interfacial patterns. A pronounced cancer suppressing activity towards at least two cancer cells, breast cancer MDA-MB-231 and human glioblastoma U87 cancer lines, was demonstrated in vitro. After a short treatment at the thinly stratified self-organized plasma-liquid interface pattern, the cancer inhibiting media demonstrate pronounced suppressing and apoptotic activities towards tumor cells. Importantly, this would have been impossible without interfacial stratification of plasma jet to thin (of several µm) current filaments, which plays a pivotal role in building up the cancer inhibition properties. Furthermore, thinly stratified, self-organized interfacial discharge is capable to efficiently control the ROS and RNS concentrations in the cancer-inhibiting media. In particular, abnormal ROS/RNS ratios are not achievable in discharges since they do not form stratified thin-filament patterns. Our findings could be tremendously important for understanding the cancer proliferation problem and hence, the potential of this approach in tackling the challenges of high cancer-induced mortality should be explored.

Iron and thiol redox signaling in cancer: An exquisite balance to escape ferroptosis

Epidemiological data indicate a constant worldwide increase in cancer mortality, although the age of onset is increasing. Recent accumulation of genomic data on human cancer via next-generation sequencing confirmed that cancer is a disease of genome alteration. In many cancers, the Nrf2 transcription system is activated via mutations either in Nrf2 or Keap1 ubiquitin ligase, leading to persistent activation of the genes with antioxidative functions. Furthermore, deep sequencing of passenger mutations is clarifying responsible cancer causative agent(s) in each case, including aging, APOBEC activation, smoking and UV. Therefore, it is most likely that oxidative stress is the principal initiating factor in carcinogenesis, with the involvement of two essential molecules for life, iron and oxygen. There is evidence based on epidemiological and animal studies that excess iron is a major risk for carcinogenesis, suggesting the importance of ferroptosis-resistance. Microscopic visualization of catalytic Fe(II) has recently become available. Although catalytic Fe(II) is largely present in lysosomes, proliferating cells harbor catalytic Fe(II) also in the cytosol and mitochondria. Oxidative stress catalyzed by Fe(II) is counteracted by thiol systems at different functional levels. Nitric oxide, carbon monoxide and hydrogen (per)sulfide modulate these reactions. Mitochondria generate not only energy but also heme/iron sulfur cluster cofactors and remain mostly dysfunctional in cancer cells, leading to Warburg effects. Cancer cells are under persistent oxidative stress with a delicate balance between catalytic iron and thiols, thereby escaping ferroptosis. Thus, high-dose L-ascorbate and non-thermal plasma as well as glucose/glutamine deprivation may provide additional benefits as cancer therapies over preexisting therapeutics.

Meristem Plant Cells as a Sustainable Source of Redox Actives for Skin Rejuvenation

Recently, aggressive advertisement claimed a “magic role” for plant stem cells in human skin rejuvenation. This review aims to shed light on the scientific background suggesting feasibility of using plant cells as a basis of anti-age cosmetics. When meristem cell cultures obtained from medicinal plants are exposed to appropriate elicitors/stressors (ultraviolet, ultrasound ultraviolet (UV), ultrasonic waves, microbial/insect metabolites, heavy metals, organic toxins, nutrient deprivation, etc.), a protective/adaptive response initiates the biosynthesis of secondary metabolites. Highly bioavailable and biocompatible to human cells, low-molecular weight plant secondary metabolites share structural/functional similarities with human non-protein regulatory hormones, neurotransmitters, pigments, polyamines, amino-/fatty acids. Their redox-regulated biosynthesis triggers in turn plant cell antioxidant and detoxification molecular mechanisms resembling human cell pathways. Easily isolated in relatively large quantities from contaminant-free cell cultures, plant metabolites target skin ageing mechanisms, above all redox imbalance. Perfect modulators of cutaneous oxidative state via direct/indirect antioxidant action, free radical scavenging, UV protection, and transition-metal chelation, they are ideal candidates to restore photochemical/redox/immune/metabolic barriers, gradually deteriorating in the ageing skin. The industrial production of plant meristem cell metabolites is toxicologically and ecologically sustainable for fully “biological” anti-age cosmetics.