New insights on molecular internalization and drug delivery following plasma jet exposures

Effects of discharge plasma on seed germination and volatile compounds content of Agropyron Mongolicum

To investigate the effects of discharge plasma on Agropyron mongolicum seeds, various treatments including direct exposure to discharge plasma, combined treatment with discharge plasma and plasma-activated water (PAW) were applied to the seeds. The changes in germination rate, MDA content, and volatile compound levels of Agropyron mongolicum seeds after different treatments were examined. The results showed that the direct effect of plasma had no significant effect on the MDA content or germination rate of Agropyron mongolicum seeds due to the limited penetration depth. However, the combined effect of plasma and activated water could cause active nitrogen and oxygen particles to enter the seeds and cause oxidative stress damage. After 18 h of combined treatment, the MDA content increased significantly, and the germination rate decreased to below the semilethal dose, which was 33.44 %. After plasma treatment, 55 volatile compounds, mainly alcohols, aldehydes and ketones, were identified from the seeds of Agropyron mongolicum. Due to the oxidation and modification of the plasma, the content of most aldehydes increased with increasing reaction time. After screening, 13 volatile organic compounds could be used as potential markers to distinguish between different treatment methods. These results reveal the mechanism underlying the biological effects of plasma treatment on Agropyron mongolicum seeds.

Comprehensive studies on the biological activities of human metastatic (MDA-MB-231) and non-metastatic (MCF-7) breast cancer cell lines, directly or combinedly treated using non-thermal plasma-based approaches

Progressive incidence and a pessimistic survival rate of breast cancer in women worldwide remains one of the most concerning topics. Progressing research indicates a potentially high effectiveness of use cold atmospheric plasma (CAP) systems. The undoubted advantage seems its simplicity in combination with other anti-cancer modalities. Following observed trend of studies, one inventory CAP system was applied to directly treat human breast cancer cell lines and culturing in two different Plasma Activated Media (PAM) for combined utilization. Proposed CAP treatments on MCF-10 A, MCF-7, and MDA-MB-231 cell lines were studied in terms of impact on cell viability by MTT assay. Disturbances in cell motility following direct and combined CAP application were assessed by scratch test. Finally, the induction of apoptosis and necrosis was verified with annexin V and propidium iodide staining. Reactive species generated during CAP treatment were determined based on optical emission spectrometry analysis along with colorimetric methods to qualitatively assess the NO2-, NO3-, H2O2, and total ROS with free radicals concentration. The most effective approach for CAP utilization was combined treatment, leading to significant disruption in cell viability, motility and mostly apoptosis induction in breast cancer cell lines. Determined CAP dose allows for mild outcome, showing insignificant harm for the non-cancerous MCF-10 A cell line, while the highly aggressive MDA-MB-231 cell line shows the highest sensitivity on proposed CAP treatment. Direct CAP treatment seems to drive the cells into the sensitive state in which the effectiveness of PAM is boosted. Observed anti-cancer response of CAP treatment was mostly triggered by RNS (mostly NO2- ions) and ROS along with free radicals (such as H2O2, OH•, O2-•, 1O2, HO2•). The combined application of one CAP source represent a promising alternative in the development of new and effective modalities for breast cancer treatment.

Toxicity study of rats treated by plasma-activated solution

Background

Cold atmospheric plasma (CAP) is an effective treatment for various skin diseases. Plasma-activated solution (PAS) is an indirect method of CAP treatment that produces biological effects similar to those of direct treatment with plasma devices. The anticancer and bacteriostatic effects of PAS have been demonstrated in vitro experiments; however, on the basis of the lack of toxicological studies on PAS, its effects on living mammals when administered by subcutaneous injection is poorly known.

Purpose

The purpose of this study was to evaluate the effects of PAS on local skin tissue cells, blood system, heart, liver, lungs, kidneys and other vital organs of the rat when injected subcutaneously.

Methods

PAS was prepared by CAP irradiation of phosphate-buffered saline (PBS). PBS and different PBS groups (CAP irradiation for 1, 3, or 5 min) were injected subcutaneously once every 48 h. The rats were euthanized immediately after 10 cycles of therapy.

Results

No adverse effects were observed during the entire period of the experiment. Histopathological examination of organs and tissues revealed no structural changes. Moreover, no obvious structural changes were observed in skin tissue. DNA damage and cancerous proliferative changes were not detected in skin tissue treated with PAS. Subsequently, RNA sequencing and western blotting were performed. The results showed that PAS increased the expression of growth factors like transforming growth factor beta (TGF-β) and vascular endothelial growth factor A (VEGFA). These results might be directly linked to the role of PAS in stimulating TGF-β receptor signaling pathway and angiogenesis.

Conclusion

The results showed that multiple subcutaneous injections of PAS did not show significant toxic side effects on local skin tissues and some vital organs in rats, providing a scientific basis to support the future treatment of skin diseases with PAS.

Cold plasma-treated medium preferentially eliminates doxorubicin-resistant osteosarcoma cells

Osteosarcoma (OS) is an aggressive bone cancer with poor prognosis, largely due to the limited effectiveness of current treatments such as doxorubicin (DX). Developing ways to overcome DX resistance is a significant clinical challenge. Here, we used two DX-resistant models to study the potential of Cold Plasma Treated Medium (PTM) to prevent DX resistance in OS. During the acquisition of the resistant phenotype upon long-term DX exposure, OS resistant cells became less proliferative, overexpressed the drug resistance-related efflux pump MDR1 and displayed a concomitant loss of SOD2 or GPX1. According to the reduced expression of these antioxidant enzymes, PTM treatment produced higher levels of oxidative express and was more effective in eradicating DX-resistant cells. Moreover, PTM reduced the expression of MDR1, thus sensitizing resistant cells to DX. These findings uncover new vulnerabilities of DX-resistant cells related with their inability to cope with excessive oxidative stress and their dependence on MDR1 that can be exploited using PTM-based treatments to provide new therapeutic approaches for the management of drug resistance in OS.

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.

Molecular dynamics simulation of the transmembrane transport process of reactive species under the synergistic effect of plasma oxidation and an electric field

Cold atmospheric pressure plasma (CAP)-assisted cancer therapy has become a popular topic in plasma biomedical research. Membrane lipid oxidation and local electric fields are two important factors in plasma-cell interactions, and the study of their synergistic effect is highly significant for optimizing the regulatory mechanism of the plasma-induced apoptosis of cancer cells. In this paper, a model of oxidized phospholipids was established, and the transmembrane process of reactive species was simulated by the classical molecular dynamics (MD) method under the conditions of oxidation and an electric field. The results showed that hydrophilic reactive oxygen species could not penetrate the membrane lipids through oxidation. The formation of electroporation provided a new channel for reactive species to penetrate the membrane, and the oxidation effect reduced the electric field threshold of membrane electroporation. Our simulation could provide theoretical support for the plasma-induced apoptosis of cancer cells at the microscopic level, provide mechanistic guidance for the practical application of plasma-induced cancer therapy, and promote the development of CAP in the field of cancer therapy.

Increased radiosensitivity of melanoma cells through cold plasma pretreatment mediated by ICG

Radiation therapy (RT) is the primary treatment for many cancers, but its effectiveness is reduced due to radioresistance and side effects. The study aims to investigate an emerging treatment for cancer, cold atmospheric plasma (CAP), as a selectable treatment between cancerous and healthy cells and its role in the occurrence of photodynamic therapy (PDT) utilizing indocyanine green (ICG) as a photosensitizer. We examined whether the efficiency of radiotherapy could be improved by combining CAP with ICG. The PDT effect induced by cold plasma irradiation and the radiosensitivity of ICG were investigated on DFW and HFF cell lines. Then, for combined treatment, ICG was introduced to the cells and treated with radiotherapy, followed by cold plasma treatment simultaneously and 24-h intervals. MTT and colony assays were used to determine the survival of treated cells, and flow cytometry was used to identify apoptotic cells. Despite a decrease in the survival of melanoma cells in CAP, ICG did not affect RT. Comparing the ICG + CAP group with CAP, a significant reduction in cell survival was observed, confirming the photodynamic properties of plasma utilizing ICG. The treatment outcome depends on the duration of CAP. The results for healthy and cancer cells also confirmed the selectivity of plasma function. Moreover, cold plasma sensitized melanoma cells to radiotherapy, increasing treatment efficiency. Treatment of CAP with RT can be effective in treating melanoma. The inclusion of ICG results in plasma treatment enhancement. These findings help to select an optimal strategy for a combination of plasma and radiotherapy.

Current Status and Future Trends of Cold Atmospheric Plasma as an Oncotherapy

Cold atmospheric plasma (CAP), a redox modulation tool, is capable of inhibiting a wide spectrum of cancers and has thus been proposed as an emerging onco-therapy. However, with incremental successes consecutively reported on the anticancer efficacy of CAP, no consensus has been made on the types of tumours sensitive to CAP due to the different intrinsic characteristics of the cells and the heterogeneous design of CAP devices and their parameter configurations. These factors have substantially hindered the clinical use of CAP as an oncotherapy. It is thus imperative to clarify the tumour types responsive to CAP, the experimental models available for CAP-associated investigations, CAP administration strategies and the mechanisms by which CAP exerts its anticancer effects with the aim of identifying important yet less studied areas to accelerate the process of translating CAP into clinical use and fostering the field of plasma oncology.

A novel approach to expedite wound healing with plasma brush of cold flame

Excessive or persistent infection is a major contributing factor in impeding chronic wound healing. Wound bed preparations using antiseptics do not necessarily target the entire bacterial spectrum, and the highly proliferating granulation tissue may be sensitive to the cytotoxic effects, impairing tissue repair. Non-thermal gas atmospheric pressure plasmas are partially ionized gases that contain highly reactive particles while the gas phase remains near room temperature, thus having the capability of accessing small irregular cavities and fissures and killing bacteria because of the diffusive nature of gas phase plasma species that are chemically reactive, providing an ideal approach to topical wound disinfection. A non-thermal plasma brush device of novel design has been developed that is suitable for clinical application in the disinfection of oral and wound bacteria. In vivo studies have indicated that the plasma brush treatment rendered no harmful effect on healthy skin or tissues, while it could improve wound healing in Pseudomonas aeruginosa biofilm infected wounds exposed to an optimized treatment with argon plus 1% nitrogen (Ar + N2) plasma.

Metrology of Ar-N2/O2 Mixture Atmospheric Pressure Pulsed DC Jet Plasma and its Application in Bio-Decontamination

Atmospheric pressure plasma jets are gaining a lot of attention due to their widespread applications in the field of bio-decontamination, polymer modification, material processing, deposition of thin film, and nanoparticle fabrication. Herein, we are reporting the disinfection of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli bacteria using plasma jet. In this regard, Ar-O₂, Ar-N₂, and Ar-O₂-N₂ mixture plasma is generated and characterized using optical and electrical characterization. Variation in plasma parameters like electron temperature, electron density, and reactive species production is monitored with discharge parameters such as applied voltage and feed gas concentration. Results show that the peak average power consumed in Ar-O₂, Ar-N₂, and Ar-O₂-N₂ mixture plasma is found to be 4.45, 2.93, and 4.35 W respectively, at 8 kV. Moreover, it is noted that by increasing applied voltage, the electron temperature, electron density, and reactive species production also increases. It is worth noting that electron temperature increases with increase in oxygen concentration in the mixture (, while it decreases with increase in nitrogen concentration in the mixture (Ar-N₂). Similarly, a decreasing trend in electron temperature is noted for Ar-O₂-N₂ mixture plasma. On the other hand, a decreasing trend in electron density is noted for all the mixtures. Reduction in viable colonies of Pseudomonas aeruginosa, Staphylococcus Aureus, and Escherichia coli were confirmed by the serial dilution method. The inactivation efficiency of pulsed DC plasma generated, in the Ar-N₂ mixture at 8 kV and 6 KHz, was evaluated against P. aeruginosa, S. aureus and E. coli bacteria by measuring the number of surviving cells versus plasma treatment time. Results showed that after 240 s of plasma treatment, the number of survival colonies of the mentioned bacteria was reduced to less than 30 CFU/mL.

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

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

Portable Cold Atmospheric Plasma Patch-Mediated Skin Anti-Inflammatory Therapy

Although plasma is a promising technology in various fields, its clinical application is restricted by several limitations. A cold atmospheric plasma (CAP) patch is fabricated to help overcome hurdles, especially when treating skin diseases. This patch has surface dielectric barrier discharge, which generates reactive oxygen species (ROS) and reactive nitrogen species (RNS) on a flexible polymer film surface on which the embedded electrode induces a locally strong electric field. The effect of the CAP patch on psoriasis is also evaluated. The distinct characteristics of psoriasis between the lesion and non-lesion area allow the CAP patch to be suitable for only lesion area for its treatment. The CAP patch induces the opening of calcium channels in keratinocytes, thereby restoring abnormal keratinocyte differentiation and the collapse of the tight junction; thus, alleviating psoriatic symptoms. In addition, the favorable effect is due to the induction of ROS/RNS by the CAP patch, not the electric field generated during plasma generation. The findings indicate that the proposed portable CAP patch can help treat inflammatory skin disorders, especially psoriasis. As this can be used easily as a combination therapy with existing drugs, it may help reduce side effects caused by existing drugs.

The Effect of Plasma on Bacteria and Normal Cells in Infected Wound

Infected wound is one of the most common and serious problem in wound management. Cold atmospheric plasma (CAP) is considered to have a good effect in wound healing as a new type medicine. However, there is a key issue that has not been addressed in the treatment of infected wounds by plasma. Bacteria are always found in the deep region of the wound. When plasma is used to treat wounds, it also acts on normal tissue cells while decontaminating. What is the difference between the same dose of plasma acting on bacteria and normal cells? In this study, the most common bacteria (S. aureus, P. aeruginosa, and E. coli) in infected wound and two kinds of normal skin cells (human keratinocyte and human skin fibroblasts (HSF)) were selected to study the difference of the effects of the same dose of plasma on bacteria and cells. The results reveal that three kinds of 10⁶ CFU mL bacteria could be effectively inactivated by 5 order after plasma treatment 3 min, and P. aeruginosa was more sensitive to plasma (could be inactivated 5 order after 2 min treatment). The 10⁴ mL keratinocyte and HSF were treated with the same dose of plasma; keratinocyte can maintain over 90% of the activity and HSF cells can maintain over 70% of the activity. Moreover, the level of collagen I secreted by HSF increased. Therefore, cells can remain a high activity when a plasma dose capable of inactivating bacteria is applied to them.

Low-temperature argon plasma jet with cascading electrode technique for biological applications

In this study, the design, performance, and characteristics of a low-temperature argon plasma jet with cascading electrode technique (APJCE) are presented. APJCE is designed based on a tip-ring structure with a cascading ring. The effect of plasma jet driven by repetitive high-voltage microsecond pulses in APJCE structure was measured qualitatively in local surface temperature detection system. Then, by applying the generated plasma jet to biological surface and measuring and characterizing the electrical parameters, we obtained a plasma jet, which is electrically and thermally in the cold plasma regime. Simulation of the electric field distribution in the nozzle also yielded similar results to the experimental results. Finally, by cascading electrodes, we guided the plasma column to the nozzle output so that the plasma temperature within four centimeters of the nozzle output is 37 °C. The resulting plasma jets were studied by atomic emission spectroscopy and the intensity of the spectral lines of the atmospheric argon plasma jet spectra was obtained as a final experimental result at the output.

Characterization and evaluation of cold atmospheric plasma as seedborne fungal disinfectant and promoting mediator for physico-chemical characteristics of Moringa oleifera seedlings

Non-thermal atmospheric pressure plasmas are a powerful tool to impact seed germination and microbial decontamination. Air large volume atmospheric pressure glow discharge plasma was developed and investigated to improve the biological activities of Moringa oleifera seeds. Ninty ns magnetic pulse compression high voltage system was used to generate the plasma. The plasma discharges current increases with increasing applied voltage and it decreases with increasing discharge gap. There was a steady reduction in the count of seedborne fungi on the application of air cold plasma with complete elimination of fungi at ≥ 10.94 mJ per pulse. The low doses of plasma (2.46 and 4.35 mJ) induced an increase in the seed germination, a significant increase in chlorophyll content (chl a and chl b) and antioxidant activities of the seedlings emerged from soaked or wet seeds rather than dry seeds. At lower plasma doses (2.46 and 4.35 mJ) there was a significant increase in leaf area and chlorophyll content (chl a and chl b) of the seedlings that emerged from H₂O₂ soaked seeds rather than that of free from H₂O₂. The plasma was harmful when applied at higher doses (≥ 10.94 mJ) and more harmful to the wet seeds compared to the dry ones.

A van der Waals force-based adhesion study of stem cells exposed to cold atmospheric plasma jets

Cold atmospheric plasma has established its effect on cell adhesion. Given the importance of cell adhesion in stem cells, the current study investigates the effect of plasma treatment on Human Bone Marrow Mesenchymal Stem Cells (HBMMSCs) adhesion by which the differentiation and fate of cells are determined. In this paper, adhesion modification is considered not only for cell- ECM (Extra cellular Matrix), but also between suspended cells, and enhanced adhesions were found in both circumstances. Regarding the previous works, the increase of the cell–ECM adhesion during the plasma therapy was mostly attributed to the enhancement of the production and activity of integrin proteins. Nevertheless, considering the importance of van der Waals forces at the cellular level, the effect of cold plasma on VDWFs and so its effect on adhesion is investigated in this work for the first time, to the best of our knowledge. For this purpose, employing the semi-empirical methods, the role of the plasma therapy on the VDWF between the cells has been studied at three levels; (a) plasma-induced dipole formation, (b) Hammaker coefficient modification of culture medium, and c) cell roughness modification. For suspended cell condition, we conclude and support that van der Waals forces (VDWFs) enhancement has a key role in cell adhesion processes. We believe that, the present work gives a new physical insight in studying the plasma therapy method at the cellular level.

Plasma Dermatology: Skin Therapy Using Cold Atmospheric Plasma

Cold atmospheric plasma-based plasma medicine has been expanding the diversity of its specialties. As an emerging branch, plasma dermatology takes advantage of the beneficial complexity of plasma constituents (e.g., reactive oxygen and nitrogen species, UV photons, and electromagnetic emission), technical versatility (e.g., direct irradiation and indirect aqueous treatment), and practical feasibility (e.g., hand-held compact device and clinician-friendly operation). The objective of this comprehensive review is to summarize recent advances in the CAP-dominated skin therapy by broadly covering three aspects. We start with plasma optimisation of intact skin, detailing the effect of CAP on skin lipids, cells, histology, and blood circulation. We then conduct a clinically oriented and thorough dissection of CAP treatment of various skin diseases, focusing on the wound healing, inflammatory disorders, infectious conditions, parasitic infestations, cutaneous malignancies, and alopecia. Finally, we conclude with a brief analysis on the safety aspect of CAP treatment and a proposal on how to mitigate the potential risks. This comprehensive review endeavors to serve as a mini textbook for clinical dermatologists and a practical manual for plasma biotechnologists. Our collective goal is to consolidate plasma dermatology’s lead in modern personalized medicine.

Insight into the Impact of Oxidative Stress on the Barrier Properties of Lipid Bilayer Models

As a new field of oxidative stress-based therapy, cold physical plasma is a promising tool for several biomedical applications due to its potential to create a broad diversity of reactive oxygen and nitrogen species (RONS). Although proposed, the impact of plasma-derived RONS on the cell membrane lipids and properties is not fully understood. For this purpose, the changes in the lipid bilayer functionality under oxidative stress generated by an argon plasma jet (kINPen) were investigated by electrochemical techniques. In addition, liquid chromatography-tandem mass spectrometry was employed to analyze the plasma-induced modifications on the model lipids. Various asymmetric bilayers mimicking the structure and properties of the erythrocyte cell membrane were transferred onto a gold electrode surface by Langmuir-Blodgett/Langmuir-Schaefer deposition techniques. A strong impact of cholesterol on membrane permeabilization by plasma-derived species was revealed. Moreover, the maintenance of the barrier properties is influenced by the chemical composition of the head group. Mainly the head group size and its hydrogen bonding capacities are relevant, and phosphatidylcholines are significantly more susceptible than phosphatidylserines and other lipid classes, underlining the high relevance of this lipid class in membrane dynamics and cell physiology.

Aurora Borealis in dentistry: The applications of cold plasma in biomedicine

Plasma is regularly alluded to as the fourth form of matter. Its bounty presence in nature along with its potential antibacterial properties has made it a widely utilized disinfectant in clinical sciences. Thermal plasma and non-thermal (or cold atmospheric) plasma (NTP) are two types of plasma. Atoms and heavy particles are both available at the same temperature in thermal plasma. Cold atmospheric plasma (CAP) is intended to be non-thermal since its electrons are hotter than the heavier particles at ambient temperature. Direct barrier discharge (DBD), atmospheric plasma pressure jet (APPJ), etc. methods can be used to produce plasma, however, all follow a basic concept in their generation. This review focuses on the anticipated uses of cold atmospheric plasma in dentistry, such as its effectiveness in sterilizing dental instruments by eradicating bacteria, its advantage in dental cavity decontamination over conventional methods, root canal disinfection, its effects on tooth whitening, the benefits of plasma treatment on the success of dental implant placement, and so forth. Moreover, the limitations and probable solutions has also been anticipated. These conceivable outcomes thus have proclaimed the improvement of more up-to-date gadgets, for example, the plasma needle and plasma pen, which are efficient in treating the small areas like root canal bleaching, biofilm disruption, requiring treatment in dentistry.

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Non-thermal plasma (NTP) has regarded as an important tool for biomedical application especially dental application.

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The surface application of NTP can be used for disinfecting microbial infection in endodontic issues.

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NTP can be used to eradicate the microorganism biofilm responsible for dental caries.

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NTP can also be utilized in would healing, implant modifications and adhesive restoration.

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NTP is potential candidate for clinical application in dentistry based on the experimental proofs.

Inhibition of corrosion causing Pseudomonas aeruginosa using plasma-activated water

AIMS

The cost of Microbiologically Influenced Corrosion (MIC) significantly affects a wide range of sectors. This study aims to assess the efficiency of a novel technology based on the use of plasma-activated water (PAW) in inhibiting corrosion caused by bacteria.

METHODS AND RESULTS

This study evaluated the effectiveness of PAW, produced by a plasma bubble reactor, in reducing corrosion causing Pseudomonas aeruginosa planktonic cells in tap water and biofilms were grown onto stainless steel (SS) coupons. Planktonic cells and biofilms were treated with PAW at different discharge frequencies (500-1500 Hz) and exposure times (0-20 min). P. aeruginosa cells in tap water were significantly reduced after treatment, with higher exposure times and discharge frequencies achieving higher reductions. Also, PAW treatment led to a gradual reduction for young and mature biofilms, achieving >4-Log reductions after 20 min. Results were also used to develop two predictive inactivation models.

CONCLUSIONS

This work presents evidence that PAW can be used to inactivate both planktonic cells and biofilms of P. aeruginosa. Experimental and theoretical results also demonstrate that reduction is dependent on discharge frequency and exposure time.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work demonstrates the potential of using PAW as means to control MIC.

The Potential Effects of Dielectric Barrier Discharge Plasma on the Extraction Efficiency of Bioactive Compounds in Radix Paeoniae Alba

Radix paeoniae alba (RPA) is a kind of herbal medicine of traditional Chinese medicine (TCM) that is widely used for the treatment of liver diseases and rheumatoid arthritis in clinical practice. As a result of the low extraction efficiency of RPA by the conventional method, many patients are given high dosages. In this study, four exposure doses of dielectric barrier discharge (DBD) plasma (0, 60, 120, and 180 s) were applied to modify the extraction efficiency of paeoniflorin, benzoylpaeoniflorin, tannic acid, gallic acid, 2′-hydroxy-4′-methoxyacetophenone, and polysaccharide in RPA. Finally, the application of plasma for 180 s exhibited a 24.6% and 12.0% (p < 0.001) increase of tannic acid and polysaccharide contents, however, a 2.1% (p < 0.05) and 5.4% (p < 0.001) reduction of paeoniflorin and gallic acid composition, respectively, and no significant difference (p > 0.05) in results obtained from benzoylpaeoniflorin and 2′-hydroxy-4′-methoxyacetophenone contents. Our results of scanning electron microscopy (SEM), automatic specific surface area and pore analyzer, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA) indicated that DBD plasma can etch the surface and undergo graft polymerization by reactive species thereby changing the water/oil holding capacity and eventually changing the extraction efficiency of bioactive compounds in RPA. Overall, our observations provide a scientific foundation for modifying the extraction efficiency of bioactive ingredients related to the pharmacological activities of RPA.

Anti-Bacterial Action of Plasma Multi-Jets in the Context of Chronic Wound Healing

This work is a contribution to the development and implementation of non-thermal plasma technology for decontamination in the perspective of nosocomial and chronic wound innovative therapies. Multi jets devices based on Plasma Gun® technology in static and scanning operation modes and bacterial lawns inoculated with resistant and non-resistant bacterial strains were designed and used. A pilot toxicity study exploring plasma treatment of wound bearing patients, performed with a low voltage plasma applicator, is documented as a first step for the translation of in vitro experiments to clinical care. Bacterial inactivation was demonstrated for Staphylococcus aureus, Pseudomonas aeruginosa and drug resistant S. aureus, P. aeruginosa and Escherichia Coli strains collected from patient wounds at Orleans (France) hospital. A few square centimeter large contaminated samples were inactivated following a single plasma exposure as short as one minute. Samples inoculated with a single but also a mix of three resistant pathogens were successfully inactivated not only right after their contamination but for mature lawns as well. Similar bactericidal action was demonstrated for antibiotic-resistant and non-resistant P. aeruginosa. The time exposure dependent increase of the inhibition spots, following multi jets exposure, is discussed as either the accumulation of reactive species or the likely combinatory action of both the reactive species and transient electric field delivery on inoculated samples.

The Anticancer Efficacy of Plasma-Oxidized Saline (POS) in the Ehrlich Ascites Carcinoma Model In Vitro and In Vivo

Cold physical plasma, a partially ionized gas rich in reactive oxygen species (ROS), is receiving increasing interest as a novel anticancer agent via two modes. The first involves its application to cells and tissues directly, while the second uses physical plasma-derived ROS to oxidize liquids. Saline is a clinically accepted liquid, and here we explored the suitability of plasma-oxidized saline (POS) as anticancer agent technology in vitro and in vivo using the Ehrlich Ascites Carcinoma (EAC) model. EAC mainly grows as a suspension in the peritoneal cavity of mice, making this model ideally suited to test POS as a putative agent against peritoneal carcinomatosis frequently observed with colon, pancreas, and ovarium metastasis. Five POS injections led to a reduction of the tumor burden in vivo as well as in a decline of EAC cell growth and an arrest in metabolic activity ex vivo. The treatment was accompanied by a decreased antioxidant capacity of Ehrlich tumor cells and increased lipid oxidation in the ascites supernatants, while no other side effects were observed. Oxaliplatin and hydrogen peroxide were used as controls and mediated better and worse outcomes, respectively, with the former but not the latter inducing profound changes in the inflammatory milieu among 13 different cytokines investigated in ascites fluid. Modulation of inflammation in the POS group was modest but significant. These results promote POS as a promising candidate for targeting peritoneal carcinomatosis and malignant ascites and suggest EAC to be a suitable and convenient model for analyzing innovative POS approaches and combination therapies.

Synergistic effect of cold atmospheric pressure plasma and free or liposomal doxorubicin on melanoma cells

The aim of the present study was to investigate combined effects of cold atmospheric plasma (CAP) and the chemotherapeutic drug doxorubicin (DOX) on murine and human melanoma cells, and normal cells. In addition to free drug, the combination of CAP with a liposomal drug (DOX-LIP) was also studied for the first time. Thiazolyl blue tetrazolium bromide (MTT) and Trypan Blue exclusion assays were used to evaluate cell viability; the mechanism of cell death was evaluated by flow cytometry. Combined treatment effects on the clonogenic capability of melanoma cells, was also tested with soft agar colony formation assay. Furthermore the effect of CAP on the cellular uptake of DOX or DOX-LIP was examined. Results showed a strong synergistic effect of CAP and DOX or DOX-LIP on selectively decreasing cell viability of melanoma cells. CAP accelerated the apoptotic effect of DOX (or DOX-LIP) and dramatically reduced the aggressiveness of melanoma cells, as the combination treatment significantly decreased their anchorage independent growth. Moreover, CAP did not result in increased cellular uptake of DOX under the present experimental conditions. In conclusion, CAP facilitates DOX cytotoxic effects on melanoma cells, and affects their metastatic potential by reducing their clonogenicity, as shown for the first time.

Prospective, comparative clinical pilot study of cold atmospheric plasma device in the treatment of atopic dermatitis

Cold atmospheric plasma generates free radicals through the ionization of air at room temperature. Its effect and safety profile as a treatment modality for atopic dermatitis lesions have not been evaluated prospectively enough. We aimed to investigate the effect and safety of cold atmospheric plasma in patients with atopic dermatitis with a prospective pilot study. Cold atmospheric plasma treatment or sham control treatment were applied respectively in randomly assigned and symmetric skin lesions. Three treatment sessions were performed at weeks 0, 1, and 2. Clinical severity indices were assessed at weeks 0, 1, 2, and 4 after treatment. Additionally, the microbial characteristics of the lesions before and after treatments were analyzed. We included 22 patients with mild to moderate atopic dermatitis presented with symmetric lesions. We found that cold atmospheric plasma can alleviate the clinical severity of atopic dermatitis. Modified atopic dermatitis antecubital severity and eczema area and severity index score were significantly decreased in the treated group. Furthermore, scoring of atopic dermatitis score and pruritic visual analog scales significantly improved. Microbiome analysis revealed significantly reduced proportion of Staphylococcus aureus in the treated group. Cold atmospheric plasma can significantly improve mild and moderate atopic dermatitis without safety issues.

Cold Atmospheric Plasma Promotes the Immunoreactivity of Granulocytes In Vitro

Cold atmospheric plasma (CAP) reduces bacteria and interacts with tissues and cells, thus improving wound healing. The CAP-related induction of neutrophils was recently described in stained sections of wound tissue in mice. Consequently, this study aimed to examine the functionality of human polymorphonuclear cells (PMN)/granulocytes through either a plasma-treated solution (PTS) or the direct CAP treatment with different plasma modes and treatment durations. PTS analysis yielded mode-dependent differences in the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) after CAP treatment. Live-cell imaging did not show any chemo-attractive or NETosis-inducing effect on PMNs treated with PTS. The time to maximum ROS production (TmaxROS) in PMNs was reduced by PTS and direct CAP treatment. PMNs directly treated with CAP showed an altered cell migration dependent on the treatment duration as well as decreased TmaxROS without inducing apoptosis. Additionally, flow cytometry showed enhanced integrin and selectin expression, as a marker of activation, on PMN surfaces. In conclusion, the modification of PMN immunoreactivity may be a main supporting mechanism for CAP-induced improvement in wound healing.

Intracellular Responses Triggered by Cold Atmospheric Plasma and Plasma-Activated Media in Cancer Cells

Cold atmospheric plasma (CAP), an ionized gas operating at room temperature, has been increasingly studied with respect to its potential use in medicine, where its beneficial effects on tumor reduction in oncology have been demonstrated. This review discusses the cellular changes appearing in cell membranes, cytoplasm, various organelles, and DNA content upon cells’ direct or indirect exposure to CAP or CAP-activated media/solutions (PAM), respectively. In addition, the CAP/PAM impact on the main cellular processes of proliferation, migration, protein degradation and various forms of cell death is addressed, especially in light of CAP use in the oncology field of plasma medicine.