Dual effects of atmospheric pressure plasma jet on skin wound healing of mice

Effectiveness of cold plasma application in oral wound healing process: A scoping review

OBJECTIVE

Cold atmospheric plasma (CAP) has shown an ability to promote wound healing by modulating biological processes without causing thermal damage. This scoping review aimed to evaluate the effectiveness of CAP application in the oral wound healing process.

DESIGN

An electronic literature search was conducted using PubMed/Medline, Embase, Web of Science, Scopus, and grey literature (Google Scholar). The search included all articles published up to October 11, 2023. Only studies focusing on the different CAP types' effects on oral cavity wounds or cells were included in the review.

RESULTS

This review analyzed 13 studies including seven cell culture studies, one animal study, and five human studies (three in vivo and two ex vivo). The findings from the reviewed articles suggest that CAP may have therapeutic potential. It can maintain cell viability and influence gene expression, accelerate wound healing, and modulate inflammation-related cytokines. DBD plasma exhibited time-sensitive effects on cellular behavior and microplasma irradiation positively impacted cell count, biochemical profiles, and cellular migration.

CONCLUSION

The application of CAP has been shown to have a positive impact on the healing of oral wounds in cell culture, animal, and human studies.

Low-temperature plasma jet suppresses bacterial colonisation and affects wound healing through reactive species

An argon-based low-temperature plasma jet (LTPJ) was used to treat chronically infected wounds in Staphylococcus aureus-laden mice. Based on physicochemical property analysis and in vitro antibacterial experiments, the effects of plasma parameters on the reactive nitrogen and oxygen species (RNOS) content and antibacterial capacity were determined, and the optimal treatment parameters were determined to be 4 standard litre per minute and 35 W. Additionally, the plasma-treated activation solution had a bactericidal effect. Although RNOS are related to the antimicrobial effect of plasma, excess RNOS may be detrimental to wound remodelling. In vivo studies demonstrated that medium-dose LTPJ promoted MMP-9 expression and inhibited bacterial growth during the early stages of healing. Moreover, LTPJ increased collagen deposition, reduced inflammation, and restored blood vessel density and TGF-β levels to normal in the later stages of wound healing. Therefore, when treating chronically infected wounds with LTPJ, selecting the medium dose of plasma is more advantageous for wound recovery. Overall, our study demonstrated that low-temperature plasma jets may be a potential tool for the treatment of chronically infected wounds.

A Nonclinical Safety Evaluation of Cold Atmospheric Plasma for Medical Applications: The Role of Genotoxicity and Mutagenicity Studies

Atmospheric nonthermal plasma (ANTP) has rapidly evolved as an innovative tool in biomedicine with various applications, especially in treating skin diseases. In particular, the formation of reactive oxygen species (ROS) and nitrogen species (RNS), which are generated by ANTP, plays an important role in the biological signaling pathways of human cells. Unfortunately, excessive amounts of these reactive species significantly result in cellular damage and cell death induction. To ensure the safe application of ANTP, preclinical in vitro studies must be conducted before proceeding to in vivo or clinical trials involving humans. Our study aimed to investigate adverse effects on genetic substances in murine fibroblast cells exposed to ANTP. Cell viability and proliferation were markedly reduced after exposing the cells with plasma. Both extracellular and intracellular reactive species, especially RNS, were significantly increased upon plasma exposure in the culture medium and the cells. Notably, significant DNA damage in the cells was observed in the cells exposed to plasma. However, plasma was not classified as a mutagen in the Ames test. This suggested that plasma led to the generation of both extracellular and intracellular reactive species, particularly nitrogen species, which affect cell proliferation and are also known to induce genetic damage in fibroblast cells. These results highlight the genotoxic and mutagenic effects of ANTP, emphasizing the need for the cautious selection of plasma intensity in specific applications to avoid adverse side effects resulting from reactive species production.

Cold atmospheric plasma is bactericidal to wound-relevant pathogens and is compatible with burn wound healing

Burn wound healing can be significantly delayed by infection leading to increased morbidity and hypertrophic scarring. An optimal antimicrobial agent would have the ability to kill bacteria without negatively affecting the host skin cells that are required for healing. Currently available products provide antimicrobial coverage, but may also cause reductions in cell proliferation and migration. Cold atmospheric plasma is a partially ionized gas that can be produced under atmospheric pressure at room temperature. In this study a novel handheld Aceso Plasma Generator was used to produce and test Aceso Cold Plasma (ACP) in vitro and in vivo. ACP showed a potent ability to eliminate bacterial load in vitro for a number of different species. Deep partial-thickness and full-thickness wounds that were treated with ACP after burning, after excision, after autografting, and at days 5, 7, and 9 did not show any negative effects on their wound healing trajectories. On par with in vitro analysis, bioburden was decreased in treated wounds vs. control. In addition, metrics of hypertrophic scar such as dyschromia, elasticity, trans-epidermal water loss (TEWL), and epidermal and dermal thickness were the same between the two treatment groups.It is likely that ACP can be used to mitigate the risk of bacterial infection during the phase of acute burn injury while patients await surgery for definitive closure. It may also be useful in treating wounds with delayed re-epithelialization that are at risk for infection and hypertrophic scarring. A handheld cold plasma device will be useful in treating all manner of wounds and surgical sites in order to decrease bacterial burden in an efficient and highly effective manner without compromising wound healing.

Effects of the application of low-temperature atmospheric plasma on titanium implants on wound healing in peri-implant connective tissue in rats

PURPOSE

This study aimed to clarify the effects of surface modification of titanium (Ti) implants by low-temperature atmospheric pressure plasma treatment on wound healing and cell attachment for biological sealing in peri-implant soft tissue.

METHODS

Hydrophilization to a Ti disk using a handheld low-temperature atmospheric pressure plasma device was evaluated by a contact angle test and compared with an untreated group. In in vivo experiments, plasma-treated pure Ti implants using a handheld plasma device (experimental group: PL) and untreated implants (control group: Cont) were placed into the rat upper molar socket, and samples were harvested at 3, 7 and 14 days after surgery. Histological evaluation was performed to assess biological sealing, collagen- and cell adhesion-related gene expression by reverse transcription quantitative polymerase chain reaction, collagen fiber detection by Picrosirius Red staining, and immunohistochemistry for integrins.

RESULTS

In in vivo experiments, increased width of the peri-implant connective tissue (PICT) and suppression of epithelial down growth was observed in PL compared with Cont. In addition, high gene expression of types I and XII collagen at 7 days and acceleration of collagen maturation was recognized in PL. Strong immunoreaction of integrin α2, α5, and β1 was observed at the implant contact area of PICT in PL.

CONCLUSIONS

The handheld low-temperature atmospheric pressure plasma device provided hydrophilicity on the Ti surface and maintained the width of the contact area of PICT to the implant surface as a result of accelerated collagen maturation and fibroblast adhesion, compared to no plasma application.

Application of cold atmospheric microwave plasma as an adjunct therapy for wound healing in dogs and cats

BACKGROUND

Cold atmospheric plasma is a novel innovative approach for wound care, and it is currently underrepresented in veterinary medicine.

OBJECTIVES

To investigate the efficacy and safety of using cold atmospheric microwave plasma (CAMP) as an adjunct therapy for wound healing in dogs and cats.

METHODS

Wound healing outcomes were retrospectively analyzed using clinical records of client-owned dogs and cats who were first managed through standard wound care alone (pre-CAMP period) and subsequently via CAMP therapy (CAMP period). The degree of wound healing was estimated based on wound size and a modified wound scoring system.

RESULTS

Of the 27 acute and chronic wounds included in the analysis, 81.48% showed complete healing after the administration of CAMP as an adjunct therapy to standard care. Most wounds achieved complete healing in < 5 weeks. Compared with the pre-CAMP period, the rate of wound healing significantly increased every week in the CAMP period in terms of in wound size (first week, p < 0.001; second week, p = 0.012; third week, p < 0.001) and wound score (first week, p < 0.001; second week, p < 0.001; third week, p = 0.001). No adverse events were noted except for mild discomfort and transient erythema.

CONCLUSIONS

CAMP is a well-tolerated therapeutic option with immense potential to support the treatment of wounds of diverse etiology in small animal practice. Further research is warranted to establish specific criteria for CAMP treatment according to wound characteristics.

An Atmospheric Plasma Jet Induces Expression of Wound Healing Genes in Progressive Burn Wounds in a Comb Burn Rat Model: A Pilot Study

Burn-related injuries are devastating injuries with a high mortality rate that affect people of all ages worldwide. We assessed the effectiveness of plasma jet treatment in altering the expression of genes involved in wound healing in a prospective longitudinal observational animal study. Six male Sprague-Dawley rats weighing 350 g were used, and burn wounds were made by applying a preheated brass comb (100°C) to the back of the rats, resulting in four full-thickness burn wounds separated by three interspaces. A total of 18 burn wounds were induced on three rats. One side of the burn, on each rat received plasma treatment (plasma group), while the other side did not (control group). The interspaces were subjected to the plasma jet for 2 minutes per day until 7 days post-wounding. Plasma treatment significantly decreased the expression of proinflammatory cytokines. Furthermore, an increase in the expression of anti-inflammatory cytokines was observed in the plasma group. We showed that plasma jet treatment could improve burn wound healing by altering the expression of genes involved in the development of wound healing.

The Regulatory Mechanism of Cold Plasma in Relation to Cell Activity and Its Application in Biomedical and Animal Husbandry Practices

As an innovative technology in biological applications, cold plasma is widely used in oral treatment, tissue regeneration, wound healing, and cancer therapy, etc., because of the adjustable composition and temperature which allow the plasma to react with bio-objects safely. Reactive oxygen species (ROS) produced by cold plasma regulate cell activity in an intensity- and time-dependent manner. A low level of ROS produced by cold plasma treatment within the appropriate intensities and times promotes proliferation of skin-related cells and increases angiogenesis, which aid in the acceleration of the wound healing process, while a high level of ROS produced by cold plasma treatment performed at a high intensity or over a long period of time inhibits the proliferation of endothelial cells, keratinocytes, fibroblasts, and cancer cells. Moreover, cold plasma can regulate stem cell proliferation by changing niche interface and producing nitric oxide directly. However, the molecular mechanism of cold plasma regulating cell activity and its potential application in the field of animal husbandry remain unclear in the literature. Therefore, this paper reviews the effects and possible regulatory mechanisms of cold plasma on the activities of endothelial cells, keratinocytes, fibroblasts, stem cells, and cancer cells to provide a theoretical basis for the application of cold plasma to skin-wound healing and cancer therapy. In addition, cold plasma exposure at a high intensity or an extended time shows excellent performances in killing various microorganisms existing in the environment or on the surface of animal food, and preparing inactivated vaccines, while cold plasma treatment within the appropriate conditions improves chicken growth and reproductive capacity. This paper introduces the potential applications of cold plasma treatment in relation to animal-breeding environments, animal health, their growth and reproduction, and animal food processing and preservation, which are all beneficial to the practice of animal husbandry and guarantee good animal food safety results.

Cold Plasma Treatment Promotes Full-thickness Healing of Skin Wounds in Murine Models

Cold plasma can be beneficial for promoting skin wound healing and has a high potential of being effectively used in treating various wounds. Our aim was to verify the effect of cold plasma in accelerating wound healing and investigate its underlying mechanism in vitro and in vivo. For the in vivo experiments, 2 full-thickness dermal wounds were created in each mouse (n = 30). While one wound was exposed to 2 daily plasma treatments for 3 min, the other wound served as a control. The wounds were evaluated by imaging and histological analyses at 4, 7, and 11 days post the wound infliction process. Immunohistochemical studies were also performed at the same time points. In vitro proliferation and scratch assay using HaCaT keratinocytes and fibroblasts were performed. The expression levels of wound healing-related genes were analyzed by real-time polymerase chain reaction and western blot analysis. On day 7, the wound healing rates were 53.94% and 63.58% for the control group and the plasma-treated group, respectively. On day 11, these rates were 76.05% and 93.44% for the control and plasma-treated groups, respectively, and the difference between them was significant (P = .039). Histological analysis demonstrated that plasma treatment promotes the formation of epidermal keratin and granular layers. Immunohistochemical studies also revealed that collagen 1, collagen 3, and alpha-smooth muscle actin appeared more abundantly in the plasma-treated group than in the control group. In vitro, the proliferation of keratinocytes was promoted by plasma exposure. Scratch assay showed that fibroblast exposure to plasma increased their migration. The expression levels of collagen 1, collagen 3, and alpha-smooth muscle actin were elevated upon plasma treatment. In conclusion, cold plasma can accelerate skin wound healing and is well tolerated.

Low Temperature Plasma Jet Affects Acute Skin Wounds in Diabetic Mice Through Reactive Components

As a common complication of diabetes, diabetic foot ulcers serious affect the life quality even lead to amputation if it's not properly treated. In this paper, we developed a Low Temperature Plasma Jet (LTPJ) system for treating diabetic foot ulcers on streptozotocin-induced diabetic mice. This system generates time-dependent reactive nitrogen and oxygen species (RNOS), which have temperature below 40°C. The wound area of normal mice was significantly reduced after LTPJ treatment. Histological and immunohistochemistry analysis showed faster deposition of collagen and more vessel formation both in plasma-treated normal and diabetic mice on Day 3. However, diabetic wounds showed poor collagen deposition and angiogenesis on Day 8, which might be the reason of slow wound healing. Reactive nitrogen species (RNS) that generated by LTPJ can promote endogenous nitric oxide (NO) production in diabetic wounds, thus promoting inflammation, stromal deposition, angiogenesis, cell proliferation and remodeling, while excess reactive oxygen species (ROS) will exacerbate oxidative stress in wound tissues of diabetic mice. In conclusion, LTPJ improved acute wound healing in normal mice, increased collagen deposition and angiogenesis in initial diabetic wound healing, but had no significant effect on diabetic wound healing rate.

Wound healing in db/db mice with type 2 diabetes using non-contact exposure with an argon non-thermal atmospheric pressure plasma jet device

A non-thermal atmospheric pressure plasma jet (APPJ) may stimulate cells and tissues or result in cell death depending on the intensity of plasma at the target; therefore, we herein investigated the effects of non-thermal plasma under non-contact conditions on the healing of full-thickness wounds in diabetic mice (DM+ group) and normal mice (DM- group). A hydrogen peroxide colorimetric method and high performance liquid chromatography showed that APPJ produced low amounts of reactive oxygen and nitrogen species. Ten-week-old male C57BL/6j mice with normal blood glucose levels (DM- group) and 10-week-old male C57BLKS/J Iar-+Leprdb/+Leprdb mice (DM+ group) received two full-thickness cutaneous wounds (4 mm in diameter) on both sides of the dorsum. Wounds were treated with or without the plasma jet or argon gas for 1 minute and were then covered with a hydrocolloid dressing (Hydrocolloid), according to which mice were divided into the following groups: DM+Plasma, DM+Argon, DM+Hydrocolloid, DM-Plasma, DM-Argon, and DM-Hydrocolloid. Exudate weights, wound areas, and wound area ratios were recorded every day. Hematoxylin and eosin staining was performed to assess re-epithelialization and α-SMA immunohistological staining to evaluate the formation of new blood vessels. Non-thermal plasma under non-contact conditions reduced the production of exudate. Exudate weights were smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups. The wound area ratio was smaller for plasma-treated wounds, and was also smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups on days 1-21 (p<0.01). Wound areas were smaller in the DM-Plasma group than in the DM-Argon group until day 14 and differences were significant on days 1-5 (p<0.01). The percentage of re-epithelialization was significantly higher in the DM+Plasma group than in the DM+Argon and DM+Hydrocolloid groups (p<0.01). The number of new blood vessels that had formed by day 7 was significantly higher in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups (p<0.05). These results indicate that treatment with the current non-thermal plasma APPJ device under non-contact conditions accelerated wound healing in diabetic mice.

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

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

Tolerance effect of a shock-free atmospheric plasma on human skin

In this work, a shock-free argon-fed plasma plume was generated by a variable-frequency power supply and the discharge characteristics were investigated from the voltage and current waveforms between 72 and 92 kHz frequencies. The higher electron temperature dominates the plasma chemical process and the average plasma temperature is about 30 ℃ under these conditions. The influence of non-thermal atmospheric plasma plume length and plume temperature on Ar gas flow is optimized at 7 sL/min. The average charge accumulation on the plume tip area and the dependence of flow rate on the plasma irradiation area were also explored. This atmospheric pressure plasma jet (APPJ) has been proposed for human-skin irradiation on different areas (even on the tongue) owing to its less painful, tingling and burning effect. Optical emission spectroscopy (OES) confirmed the presence of excited argon with reactive nitrogen (RNS) and oxygen species (ROS). This study contributes to a better understanding of non-thermal plasma effects on the human body which may find prospects for disinfection and prevention of different diseases during the current pandemic time.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00339-022-06022-w.

Cold atmospheric pressure plasmas applications in dentistry

Cold atmospheric pressure plasmas (CAP) is widely used for various therapeutic applications in health care. With the enormous progress in the understanding of plasma physics and development of plasma devices, the application of CAP is greatly promoted in dentistry. The reactive chemical species and electromagnetic radiation generated by CAP can activate and control various biochemical procedures. Therefore, CAP showed promising usage in surface modification of dental materials, biofilm removal, disinfection, endodontic therapy, periodontitis treatment, wound healing, and head and neck cancer control. Therefore, the objective of the present review is to present recently published studies on CAP in dentistry.

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.

Improving Vascularization of Biomaterials for Skin and Bone Regeneration by Surface Modification: A Narrative Review on Experimental Research

Artificial tissue substitutes are of great interest for the reconstruction of destroyed and non-functional skin or bone tissue due to its scarcity. Biomaterials used as scaffolds for tissue regeneration are non-vascularized synthetic tissues and often based on polymers, which need ingrowth of new blood vessels to ensure nutrition and metabolism. This review summarizes previous approaches and highlights advances in vascularization strategies after implantation of surface-modified biomaterials for skin and bone tissue regeneration. The efficient integration of biomaterial, bioactive coating with endogenous degradable matrix proteins, physiochemical modifications, or surface geometry changes represents promising approaches. The results show that the induction of angiogenesis in the implant site as well as the vascularization of biomaterials can be influenced by specific surface modifications. The neovascularization of a biomaterial can be supported by the application of pro-angiogenic substances as well as by biomimetic surface coatings and physical or chemical surface activations. Furthermore, it was confirmed that the geometric properties of the three-dimensional biomaterial matrix play a central role, as they guide or even enable the ingrowth of blood vessels into a biomaterial.

An active ingredient isolated from Ganoderma lucidum promotes burn wound healing via TRPV1/SMAD signaling

The mushroom Ganoderma lucidum is a traditional Chinese medicine and G. lucidum spore oil (GLSO) is the lipid fraction isolated from Ganoderma spores. We examined the effect of GLSO on burn wound healing in mice. Following wounding, GLSO was applied on the wounds twice daily. Repair analysis was performed by Sirius-Red-staining at different time points. Cell proliferation and migration assays were performed to verify the effect of GLSO on growth. Network pharmacology analysis to identify possible targets was also carried out, followed by Western blotting, nuclear translocation, cell proliferation, and immunofluorescence assays for in-depth investigation of the mechanism. Our study showed that GLSO significantly promoted cell proliferation, and network pharmacology analysis suggested that GLSO might act through transient receptor potential vanilloid receptor 1 (TRPV1)/SMAD signaling. Furthermore, GLSO elevated SMAD2/3 expression in skin burn and promoted its nuclear translocation, and TRPV1 expression was also increased upon exposure to GLSO. Cell proliferation and immunofluorescence assays with TRPV1 inhibitor showed that GLSO accelerated skin burn wound healing through TRPV1 and SMADs signaling, which provides a foundation for clinical application of GLSO in the healing of deep skin burns.

Low-intensity cold atmospheric plasma reduces wrinkles on photoaged skin through hormetic induction of extracellular matrix protein expression in dermal fibroblasts

BACKGROUND

Recent evidence indicates that cold atmospheric plasma (CAP) can upregulate the production of extracellular matrix (ECM) proteins in dermal fibroblasts and enhance transdermal drug delivery when applied at a low intensity.

OBJECTIVES

The aim of this study was to evaluate the effect of low-intensity CAP (LICAP) on photoaging-induced wrinkles in an animal model and the expression profiles of ECM proteins in human dermal fibroblasts.

METHODS

Each group was subjected to photoaging induction and allocated to therapy (LICAP, topical polylactic acid (PLA), or both). The wrinkles were evaluated via visual inspection, quantitative analysis, and histology. The expression of collagen I/III and fibronectin was assessed using reverse transcription-quantitative polymerase chain reaction, western blot analysis, and immunofluorescence. The amount of aqueous reactive species produced by LICAP using helium and argon gas was also measured.

RESULTS

Wrinkles significantly decreased in all treatment groups compared to those in the untreated control. The differences remained significant for at least 4 weeks. Dermal collagen density increased following LICAP and PLA application. LICAP demonstrated a hormetic effect on ECM protein expression in human dermal fibroblasts. The production of reactive species increased, showing a biphasic pattern, with an initial linear phase and a slow saturation phase. The initial linearity was sustained for a longer time in the helium plasma (~60 s) than in the argon plasma (~15 s).

CONCLUSION

LICAP appears to be a novel treatment option for wrinkles on the photodamaged skin. This treatment effect seems to be related to its hormetic effect on dermal ECM production.

In vivo assessment of APPJ discharge on the earthworm: coelomic TAC and MDA levels, cell death, and tissue regeneration

The effective medical applications of cold atmospheric pressure plasma jet (APPJ) have been reported by many researchers, including sterilization of liquid and solid surfaces, treatment of chronic wounds, treatment of cancer tumors, and blood clots. Therefore, in this study, we exposed Aporrectodea trapezoides and Eisenia fetida earthworms to APPJ discharge (0-30 s) to evaluate the impacts on regeneration of missed segments, apoptosis, lipid peroxidation (LPo), catalase activity (CAT), total antioxidant capacity (TAC), total proteins, and protein profile. Results showed APPJ induced significant effects on regeneration ability of earthworms after 20 and 30 s of exposure (p < 0.05). Atmospheric pressure plasma jet did not have significant effects on MDA content and TUNEL-positive cells, but this effect was significant for TAC and CAT in both species (p < 0.05). In conclusion, the present study revealed for the first time that regeneration of missed segments in earthworms can be stimulated by plasma treatment.

Improvement of Cell Growth of Uterosacral Ligament Fibroblast Derived from Pelvic Organ Prolapse Patients by Cold Atmospheric Plasma Treated Liquid

Pelvic organ prolapse (POP) is a chronic disorder that affects quality of life in women. Several POP treatments may be accompanied by abrasion, constant infection, and severe pain. Therefore, new treatment methods and improvements in current treatments for POP are required. Non-thermal atmospheric-pressure plasma is a rising biomedical therapy that generates a mixed cocktail of reactive species by different mechanisms. In this study, we applied a cylinder-type dielectric barrier discharge plasma device to create a plasma-treated liquid (PTL). The PTL was added to primary cultured human uterosacral ligament fibroblast (hUSLF) cells from POP patients at each stage. Surprisingly, treatment with diluted PTL increased hUSLF cell viability but decreased ovarian cancer cell viability. PTL also decreased cell apoptosis in hUSLF cells but increased it in SKOV3 cells. Our results suggest that PTL protects hUSLF cells from cell apoptosis by controlling the p53 pathway and improves cell viability, implying that PTL is a promising application for POP therapy.

Plasma Damage Control: From Biomolecules to Cells and Skin

The antibacterial and cell-proliferative character of atmospheric pressure plasma jets (APPJs) helps in the healing process of chronic wounds. However, control of the plasma-biological target interface remains an open issue. High vacuum ultraviolet/ultraviolet (VUV/UV) radiation and RONS flux from plasma may cause damage of a treated tissue; therefore, controlled interaction is essential. VUV/UV emission from argon APPJs and radiation control with aerosol injection in plasma effluent is the focus of this research. The aerosol effect on radiation is studied by a fluorescent target capable of resolving the plasma oxidation footprint. In addition, DNA damage is evaluated by plasmid DNA radiation assay and cell proliferation assay to assess safety aspects of the plasma jet, the effect of VUV/UV radiation, and its control with aerosol injection. Inevitable emission of VUV/UV radiation from plasmas during treatment is demonstrated in this work. Plasma has no antiproliferative effect on fibroblasts in short treatments (t < 60 s), while long exposure has a cytotoxic effect, resulting in decreased cell survival. Radiation has no effect on cell survival in the medium due to absorption. However, a strong cytotoxic effect on the attached fibroblasts without the medium is apparent. VUV/UV radiation contributes 70% of the integral plasma effect in induction of single- and double-strand DNA breaks and cytotoxicity of the attached cells without the medium. Survival of the attached cells increases by 10% when aerosol is introduced between plasma and the cells. Injection of aerosol in the plasma effluent can help to control the plasma-cell/tissue interaction. Aerosol droplets in the effluent partially absorb UV emission from the plasma, limiting photon flux in the direction of the biological target. Herein, cold and safe plasma-aerosol treatment and a safe operational mode of treatment are demonstrated in a murine model.

Medical gas plasma-stimulated wound healing: Evidence and mechanisms

Defective wound healing poses a significant burden on patients and healthcare systems. In recent years, a novel reactive oxygen and nitrogen species (ROS/RNS) based therapy has received considerable attention among dermatologists for targeting chronic wounds. The multifaceted ROS/RNS are generated using gas plasma technology, a partially ionized gas operated at body temperature. This review integrates preclinical and clinical evidence into a set of working hypotheses mainly based on redox processes aiding in elucidating the mechanisms of action and optimizing gas plasmas for therapeutic purposes. These hypotheses include increased wound tissue oxygenation and vascularization, amplified apoptosis of senescent cells, redox signaling, and augmented microbial inactivation. Instead of a dominant role of a single effector, it is proposed that all mechanisms act in concert in gas plasma-stimulated healing, rationalizing the use of this technology in therapy-resistant wounds. Finally, addressable current challenges and future concepts are outlined, which may further promote the clinical utilization, efficacy, and safety of gas plasma technology in wound care in the future.

Gas Plasma-Augmented Wound Healing in Animal Models and Veterinary Medicine

The loss of skin integrity is inevitable in life. Wound healing is a necessary sequence of events to reconstitute the body’s integrity against potentially harmful environmental agents and restore homeostasis. Attempts to improve cutaneous wound healing are therefore as old as humanity itself. Furthermore, nowadays, targeting defective wound healing is of utmost importance in an aging society with underlying diseases such as diabetes and vascular insufficiencies being on the rise. Because chronic wounds’ etiology and specific traits differ, there is widespread polypragmasia in targeting non-healing conditions. Reactive oxygen and nitrogen species (ROS/RNS) are an overarching theme accompanying wound healing and its biological stages. ROS are signaling agents generated by phagocytes to inactivate pathogens. Although ROS/RNS’s central role in the biology of wound healing has long been appreciated, it was only until the recent decade that these agents were explicitly used to target defective wound healing using gas plasma technology. Gas plasma is a physical state of matter and is a partially ionized gas operated at body temperature which generates a plethora of ROS/RNS simultaneously in a spatiotemporally controlled manner. Animal models of wound healing have been vital in driving the development of these wound healing-promoting technologies, and this review summarizes the current knowledge and identifies open ends derived from in vivo wound models under gas plasma therapy. While gas plasma-assisted wound healing in humans has become well established in Europe, veterinary medicine is an emerging field with great potential to improve the lives of suffering animals.

Cold atmospheric plasma selectively induces G0/G1 cell cycle arrest and apoptosis in AR-independent prostate cancer cells

Purpose: Androgen receptor-independent prostate cancers do not respond to androgen blockage therapies and suffer from high recurrence rate. We aim to contribute to the establishment of novel therapeutic approaches against such malignancies.

Materials and Methods: We examined whether and how cold atmospheric plasma delivers selectivity against AR-independent prostate cancers via cell viability, transwell assay, wound healing, cell apoptosis assay, flow cytometry, intracellular hydrogen peroxide determination assay, RONS scavenger assay and western blot using human normal epithelial prostatic cells PNT1A and AR-negative DU145 prostate cancer cells.

Results: We show that cold atmospheric plasma could selectively halt cell proliferation and migration in androgen receptor-independent cells as a result of induced cell apoptosis and G0/G1 stage cell cycle arrest, and such outcomes were achieved through modulations on the MAPK and NF-kB pathways in response to physical plasma induced intracellular redox level.

Conclusion: Our study reports cold atmospheric plasma induced reduction on the proliferation and migration of androgen receptor-independent prostate cancer cells that offers novel therapeutic insights on the treatment of such cancers, and provides the first evidence on physical plasma induced cell cycle G0/G1 stage arrest that warrants the exploration on the synergistic use of cold atmospheric plasma and drugs such as chemotherapies in eradicating such cancer cells.

The repetitive application of cold atmospheric plasma (CAP) improves microcirculation parameters in chronic wounds

BACKGROUND

Chronic wounds, such as venous leg ulcers, diabetic foot ulcers, and pressure ulcers, impose a significant burden on patients and health care systems worldwide. Cold atmospheric plasma (CAP) accelerates wound healing and decreases bacterial load in chronic wounds in both in vitro and in vivo experiments. For the first time, we examined the effects of a repetitive application of CAP on the microcirculation in chronic wounds.

HYPOTHESIS

The repetitive application of cold atmospheric plasma application further improves microcirculation in chronic wounds.

METHODS

Twenty patients with chronic wounds were treated repetitively with CAP. The repetitive application consisted of three CAP sessions, each lasting 90 s and separated by a 10-minute microcirculation measuring period. Microcirculation parameters were assessed with combined Laser-Doppler-Flowmetry and spectrophotometry in a tissue depth of 2 mm.

RESULTS

Tissue oxygen saturation was significantly increased after the first CAP application. The effect amplitude and duration were further increased after the second and third CAP application with a maximum increase by 16,7% (percent change; p = 0,004 vs. baseline) after the third application. There was no significant increase in capillary blood flow until the third CAP application. After the third CAP application, an increase by 22,6% (p = 0,014) was observed. Postcapillary filling pressure was not significantly increased over the measuring period. The repetitive application of CAP further enhances the microcirculation in chronic wounds compared to a single application.

CONCLUSION

The repetitive application of CAP boosts and prolongs tissue oxygen saturation and capillary blood flow in chronic wounds compared to a single application. This insight could provide an impetus for new treatment protocols.

Effects of non-thermal atmospheric pressure plasma on palatal wound healing of free gingival grafts: a randomized controlled clinical trial

OBJECTIVE

The aim of this trial was to evaluate the effects of non-thermal atmospheric pressure plasma (NAPP) on wound healing, epithelization, local pain, bleeding, and alteration of sensation in palatal donor site.

MATERIALS AND METHODS

Forty patients with inadequate attached gingiva were included in the study. Patients were divided into two groups: (i) NAPP group (Free gingival graft [FGG] + NAPP) and (ii) control group (FGG alone). NAPP was performed immediately after the operation and on days 3 and 7. Pain, bleeding, and the amount of medication were recorded by patients every day. Epithelization in donor site, alteration of sensation and color match were assessed weekly for 2 months. Inter-group comparisons of continuous variables by time were performed with two-way repeated measures ANOVA test and a general linear model. Categorical variables were compared using Chi-square exact test. A p value of < 0.05 was considered significant.

RESULTS

At week 2, the number of patients with complete epithelization was greater in the NAPP group compared to the control group (p < 0.05). Additionally, color match in donor site was better in the NAPP group than in the control group (p < 0.05) during the first five follow-up assessments. No significant difference was found between the two groups with regard to bleeding, pain level, drug use, and alteration of sensation.

CONCLUSION

The NAPP application increased the epithelization and accelerated the wound healing process although it did not decrease the level of pain and sensation.

CLINICAL RELEVANCE

Our data suggested that the NAPP application may help epithelization and thus may shorten the recovery time after oral surgeries.

Optical Emission Spectroscopy as a Diagnostic Tool for Characterization of Atmospheric Plasma Jets

A suitable technique for localized surface treatment of solid materials is an atmospheric pressure plasma jet (APPJ). The properties of the APPJ plasma often depend on small details like the concentration of gaseous impurities what influences the surface kinetics. The simplest and often most useful configuration of the APPJ is presented, characterized by optical emission spectroscopy (OES), and results are discussed in view of various papers. Furthermore, results of additional recent papers on the characterization of the APPJ by OES are presented as well. Because the APPJ is operating at atmospheric pressure, even the water vapor traces may significantly alter the type and concentration of reactive species. The APPJ sustained in noble gases represents a source of vacuum ultraviolet (VUV) radiation that is absorbed in the surface of the treated material, thus causing bond scission. The addition of minute amounts of reactive gases causes significant suppression of VUV radiation and the formation of reactive radicals. These radicals such as OH, O, N, NO, O3, and alike interact chemically with the surface causing its functionalization. Huge gradients of these radicals have been reported, so the surface finish is limited to the area reached by the radicals. Particularly OH radicals significantly prevail in the OES spectra, even when using very pure noble gas. They may cause suppression of other spectral features. OH radicals are especially pronounced in Ar plasmas. Their density decreases exponentially with a distance from the APPJ orifice.

Cold Atmospheric Plasma: A New Strategy Based Primarily on Oxidative Stress for Osteosarcoma Therapy

Osteosarcoma is the most common primary bone tumor, and its first line of treatment presents a high failure rate. The 5-year survival for children and teenagers with osteosarcoma is 70% (if diagnosed before it has metastasized) or 20% (if spread at the time of diagnosis), stressing the need for novel therapies. Recently, cold atmospheric plasmas (ionized gases consisting of UV-Vis radiation, electromagnetic fields and a great variety of reactive species) and plasma-treated liquids have been shown to have the potential to selectively eliminate cancer cells in different tumors through an oxidative stress-dependent mechanism. In this work, we review the current state of the art in cold plasma therapy for osteosarcoma. Specifically, we emphasize the mechanisms unveiled thus far regarding the action of plasmas on osteosarcoma. Finally, we review current and potential future approaches, emphasizing the most critical challenges for the development of osteosarcoma therapies based on this emerging technique.

The antimicrobial and tissue healing efficacy of the atmospheric pressure cold plasma on grade III infected pressure ulcer: randomized controlled in vivo experiment

AIM

To evaluate the antimicrobial efficacy and wound healing effect of atmospheric pressure cold plasma (APCP) on an infected pressure ulcer (IPUs) model that was created on rats.

METHODS

A total of 18 rats was divided into APCP, silver sulfadiazine (AgS) and control groups to have six rats in each group. A third-grade pressure ulcer model was developed on the back of each of the rats, and pressure ulcers were infected by inoculation of multidrug resistance (MDR) Pseudomonas aeruginosa. A portable dielectric barrier discharge device was used to generate cold air plasma. APCP, AgS and saline treatments were carried out once a day for 14 days. The effectiveness of the treatment was evaluated on days 5, 10 and 15. Surface area, depth, pressure ulcer healing scale (PUSH) and microbiological examination were used for evaluation.

RESULTS

The results of this study showed that APCP was superior over AgS application and irrigation with saline by means of the reduction in surface area and depth of ulcers. Furthermore, PUSH score in plasma group was lower than other groups and histopathological examination showed a higher epithelization in APCP group. The average reductions of MDR P. aeruginosa for APCP, AgS and control groups were determined as 5·64 ± 1·87, 1·91 ± 0·90 and 1·22 ± 0·88 log10 CFU per gram tissue, respectively.

CONCLUSION

Atmospheric pressure cold plasma healed IPUs better than AgS.

SIGNIFICANCE AND IMPACT OF THE STUDY

Portable cold plasma devices could be a potential novel treatment modality for the patients who have IPUs.

Wound Healing Effect of Nonthermal Atmospheric Pressure Plasma Jet on a Rat Burn Wound Model: A Preliminary Study

Worldwide, an estimated 6 million patients seek medical attention for burns annually. Various treatment methods and materials have been investigated and developed to enhance burn wound healing. Recently, a new technology, plasma medicine, has emerged to offer new solutions in wound care. As the development of plasma medicine has shown benefit in wound healing, we aimed to assess the effects of plasma medicine on burn wounds. To investigate the effectiveness of a nonthermal atmospheric pressure plasma jet (NAPPJ) for burn wound treatment on a brass comb burn wound rat model. Burn wounds were made by applying a preheated brass comb (100°C) for 2 minutes, which resulted in four full-thickness burn wounds separated by three interspaces. Interspaces were exposed to NAPPJ treatment for 2 minutes and morphological changes and neutrophil infiltration were monitored at 0, 4, and 7 days post-wounding. The percentage of necrotic interspace was higher in the control group than in the plasma-treated group (51.8 ± 20.5% vs 31.5 ± 19.0%, P < .001). Moreover, the exposure of interspace to NAPPJ greatly reduced the number of infiltrating neutrophils. In addition, the percentage of interspace that underwent full-thickness necrosis in the plasma-treated group was smaller than that in the control group (28% vs 67%). NAPPJ exposure on interspaces has a positive effect on burn wounds leading to wound healing by reducing burn injury progression.

Development and Characterization of a Non-Thermal Plasma Source for Therapeutic Treatments

OBJECTIVE

an innovative non-thermal plasma (NTP) system constituted by a radiofrequency (RF) power generator directly coupled to a treatment probe is described and characterized. This system is intended to be applied as a medical device for therapeutic treatments.

METHODS

electrical characterization of the radiofrequency power generator supplying the treatment probe was performed. Meanwhile, generated NTP was optically analyzed. Obtained data were studied to establish the safety profile of plasma application on heat sensitive matter.

RESULTS

the NTP system was validated through bacterial deactivation trials, as well as, of being capable of deactivating carcinogenic cells. Besides promoting and accelerating wound closure in vivo performed in mice, demonstrating faster healing than that done with conventional treatments.

CONCLUSION

the NTP system's characterization is an essential stage to determine the adequate application of the generated plasma over organic media. The therapeutic benefits of the NTP system were proved by the development of in vivo experiences involving laboratory mice.

SIGNIFICANCE

the generated NTP interacts with surrounding air particles producing reactive oxygen and nitrogen species, which, exhibit bactericidal and antiseptic effects due to their strong biochemical reactivity; functioning like critical mediators in animal physiology and promoting wound healing processes. These properties make the NTP system a feasible technology intended for therapeutic treatments.

Autologous Platelet-Rich Plasma Enhances the Healing of Large Cutaneous Wounds in Dogs

Platelet-rich plasma (PRP) is known to play a crucial role in skin wound healing, in both Human and Veterinary Medicine. Remarkably, until now, no studies have reported PRP treatment in subacute full-thickness skin wounds of the dog. The aim of this study was to evaluate the effects of two consecutive applications of autologous PRP, with the second application after 15 days, in 6 dogs showing large subacute skin wounds. The percentage of contraction, re-epithelialization and healing in all treated patients indicated that no complications or side effects, associated with consecutive PRP treatments, occurred in any patient and all wounds achieved complete closure and re-epithelialization. Our results suggest a positive effect of repeated autologous topical PRP treatments in large cutaneous subacute wounds of different etiology. Therefore, this PRP treatment could represent a simple, cost-effective, and valid alternative to promote healing processes in subacute large wounds cases in dogs.

ZNRD1 and Its Antisense Long Noncoding RNA ZNRD1-AS1 Are Oppositely Regulated by Cold Atmospheric Plasma in Breast Cancer Cells

Cold atmospheric plasma (CAP) has been recognized as a potential alternative or supplementary cancer treatment tool, which is attributed by its selective antiproliferation effect on cancer cells over normal cells. Standardization of the CAP treatment in terms of biological outputs such as cell growth inhibition and gene expression change is essential for its clinical application. This study aims at identifying genes that show consistent expression profiles at a specific CAP condition, which could be used to monitor whether CAP is an appropriate treatment to biological targets. To do this, genes showing differential expression by two different CAP treatment conditions were screened in the MCF-7 breast cancer cells. As a result, ZNRD1 was identified as a potential marker with being consistently upregulated by 600 s but downregulated by the 10 × 30 s CAP treatment scheme. Expression of ZNRD1 was increased in breast cancer tissues compared to normal tissues, judged by cancer tissue database analysis, and supported by the antiproliferation after siRNA-induced downregulation in MCF-7. Interestingly, the antisense long noncoding RNA (lncRNA) of ZNRD1, ZNRD1-AS1, was regulated to the opposite direction of ZNRD1 by CAP. The siRNA-based qPCR analysis indicates that ZNRD1 downregulates ZNRD1-AS1, but not vice versa. ZNRD1-AS1 was shown to increase a few cis-genes such as HLA-A, HCG9, and PPP1R11 that were also regulated by CAP. Altogether, this study identified a pair of gene and its antisense lncRNA of which expression is precisely controlled by CAP in a dose-dependent manner. These genes could help elucidate the molecular mechanism how CAP regulates lncRNAs in cancer cells.

Long-Term Risk Assessment for Medical Application of Cold Atmospheric Pressure Plasma

Despite increasing knowledge gained based on multidisciplinary research, plasma medicine still raises various questions regarding specific effects as well as potential risks. With regard to significant statements about in vivo applicability that cannot be prognosticated exclusively based on in vitro data, there is still a deficit of clinical data. This study included a clinical follow-up of five probands who had participated five years previously in a study on the influence of cold atmospheric pressure plasma (CAP) on the wound healing of CO2 laser-induced skin lesions. The follow-up included a complex imaging diagnostic involving dermatoscopy, confocal laser scanning microscopy (CLSM) and hyperspectral imaging (HSI). Hyperspectral analysis showed no relevant microcirculatory differences between plasma-treated and non-plasma-treated areas. In summary of all the findings, no malignant changes, inflammatory reactions or pathological changes in cell architecture could be detected in the plasma-treated areas. These unique in vivo long-term data contribute to a further increase in knowledge about important safety aspects in regenerative plasma medicine. However, to confirm these findings and secure indication-specific dose recommendations, further clinical studies are required.

Long-term Risk Assessment for Medical Application of Cold Atmospheric Pressure Plasma

Despite increasing knowledge gained based on multidisciplinary research, plasma medicine still raises various questions regarding specific effects as well as potential risks. With regard to significant statements about in vivo applicability that cannot be prognosticated exclusively based on in vitro data, there is still a deficit of clinical data. This study included a clinical follow-up of five probands who had participated five years previously in a study on the influence of cold atmospheric pressure plasma (CAP) on the wound healing of CO₂ laser-induced skin lesions. The follow-up included a complex imaging diagnostic involving dermatoscopy, confocal laser scanning microscopy (CLSM) and hyperspectral imaging (HSI). Hyperspectral analysis showed no relevant microcirculatory differences between plasma-treated and non-plasma-treated areas. In summary of all the findings, no malignant changes, inflammatory reactions or pathological changes in cell architecture could be detected in the plasma-treated areas. These unique in vivo long-term data contribute to a further increase in knowledge about important safety aspects in regenerative plasma medicine. However, to confirm these findings and secure indication-specific dose recommendations, further clinical studies are required.

Cold Plasma-Treated Ringer's Saline: A Weapon to Target Osteosarcoma

Osteosarcoma (OS) is the main primary bone cancer, presenting poor prognosis and difficult treatment. An innovative therapy may be found in cold plasmas, which show anti-cancer effects related to the generation of reactive oxygen and nitrogen species in liquids. In vitro models are based on the effects of plasma-treated culture media on cell cultures. However, effects of plasma-activated saline solutions with clinical application have not yet been explored in OS. The aim of this study is to obtain mechanistic insights on the action of plasma-activated Ringer’s saline (PAR) for OS therapy in cell and organotypic cultures. To that aim, cold atmospheric plasma jets were used to obtain PAR, which produced cytotoxic effects in human OS cells (SaOS-2, MG-63, and U2-OS), related to the increasing concentration of reactive oxygen and nitrogen species generated. Proof of selectivity was found in the sustained viability of hBM-MSCs with the same treatments. Organotypic cultures of murine OS confirmed the time-dependent cytotoxicity observed in 2D. Histological analysis showed a decrease in proliferating cells (lower Ki-67 expression). It is shown that the selectivity of PAR is highly dependent on the concentrations of reactive species, being the differential intracellular reactive oxygen species increase and DNA damage between OS cells and hBM-MSCs key mediators for cell apoptosis.

Physical plasma and leukocytes - immune or reactive?

Leukocytes are professionals in recognizing and removing pathogenic or unwanted material. They are present in virtually all tissues, and highly motile to enter or leave specific sites throughout the body. Less than a decade ago, physical plasmas entered the field of medicine to deliver their delicate mix of reactive species and other physical agents for mainly dermatological or oncological therapy. Plasma treatment thus affects leukocytes via direct or indirect means: immune cells are either present in tissues during treatment, or infiltrate or exfiltrate plasma-treated areas. The immune system is crucial for human health and resolution of many types of diseases. It is therefore vital to study the response of leukocytes after plasma treatment in vitro and in vivo. This review gathers together the major themes in the plasma treatment of innate and adaptive immune cells, and puts these into the context of wound healing and oncology, the two major topics in plasma medicine.

Modulation of Metamorphic and Regenerative Events by Cold Atmospheric Pressure Plasma Exposure in Tadpoles, Xenopus laevis

Atmospheric pressure plasma has found wide clinical applications including wound healing, tissue regeneration, sterilization, and cancer treatment. Here, we have investigated its effect on developmental processes like metamorphosis and tail regeneration in tadpoles. Plasma exposure hastens the process of tail regeneration but delays metamorphic development. The observed differences in these two developmental processes following plasma exposure are indicative of physiological costs associated with developmental plasticity for their survival. Ultrastructural changes in epidermis and mitochondria in response to the stress of tail amputation and plasma exposure show characteristics of cellular hypoxia and oxidative stress. Mitochondria show morphological changes such as swelling with wide and fewer cristae and seem to undergo processes such as fission and fusion. Complex interactions between calcium, peroxisomes, mitochondria and their pore transition pathways are responsible for changes in mitochondrial structure and function, suggesting the subcellular site of action of plasma in this system.

Regeneration and Repair of Skin Wounds: Various Strategies for Treatment

Skin as a mechanical barrier between the inner and outer environment of our body protects us against infection and electrolyte loss. This organ consists of 3 layers: the epidermis, dermis, and hypodermis. Any disruption in the integrity of skin leads to the formation of wounds, which are divided into 2 main categories: acute wounds and chronic wounds. Generally, acute wounds heal relatively faster. In contrast to acute wounds, closure of chronic wounds is delayed by 3 months after the initial insult. Treatment of chronic wounds has been one of the most challenging issues in the field of regenerative medicine, promoting scientists to develop various therapeutic strategies for a fast, qualified, and most cost-effective treatment modality. Here, we reviewed more recent approaches, including the development of stem cell therapy, tissue-engineered skin substitutes, and skin equivalents, for the healing of complex wounds.

Cold atmospheric plasma promotes different types of superficial skin erosion wounds healing

Superficial skin erosion wounds are very common in the clinic, and conventional treatments are not always effective; thus, effective and novel therapy is needed. Cold atmospheric plasma (CAP) has been recognised as a promising approach to wound healing. The purpose of this study is to show the potential clinical application of CAP for the healing of different kinds of superficial skin wounds. Seven patients with different kinds of superficial skin wounds (two patients with pyoderma gangrenosum, two patients with trauma would, one patient with giant genital wart, one patient with diabetic foot, and one patient with chronic eczema) were recruited to this study. All patients accepted and received CAP treatment every other day till the wound healed. The expected results were complete wound healing after CAP treatment. All patients achieved complete wound healing after several rounds (range from two to eight) of CAP treatment, and there was no side effect observed. CAP may provide a new and effective choice to solve the problem of the healing of superficial wounds that are not only caused by trauma but also because of eczema. CAP has certain value in the treatment of superficial skin diseases in the future.

Short exposure to cold atmospheric plasma induces senescence in human skin fibroblasts and adipose mesenchymal stromal cells

Cold Atmospheric Plasma (CAP) is a novel promising tool developed in several biomedical applications such as cutaneous wound healing or skin cancer. Nevertheless, in vitro studies are lacking regarding to CAP effects on cellular actors involved in healthy skin healing and regarding to the mechanism of action. In this study, we investigated the effect of a 3 minutes exposure to CAP-Helium on human dermal fibroblasts and Adipose-derived Stromal Cells (ASC) obtained from the same tissue sample. We observed that CAP treatment did not induce cell death but lead to proliferation arrest with an increase in p53/p21 and DNA damages. Interestingly we showed that CAP treated dermal fibroblasts and ASC developed a senescence phenotype with p16 expression, characteristic morphological changes, Senescence-Associated β-galactosidase expression and the secretion of pro-inflammatory cytokines defined as the Senescence-Associated Secretory Phenotype (SASP). Moreover this senescence phenotype is associated with a glycolytic switch and an increase in mitochondria content. Despite this senescence phenotype, cells kept in vitro functional properties like differentiation potential and immunomodulatory effects. To conclude, we demonstrated that two main skin cellular actors are resistant to cell death but develop a senescence phenotype while maintaining some functional characteristics after 3 minutes of CAP-Helium treatment in vitro.

Effect of cold atmospheric plasma treatment on the metabolites of human leukemia cells

Background

Acute myeloid leukemia (AML) is a typically fatal malignancy and new drug and treatment need to be developed for a better survival outcome. Cold atmospheric plasma (CAP) is a novel technology, which has been widely applied in biomedicine, especially in various of cancer treatment. However, the changes in cell metabolism after CAP treatment of leukemia cells have been rarely studied.

Methods

In this study, we investigated the metabolite profiling of plasma treatment on leukemia cells based on Gas Chromatography Tandem Time-of-Flight Mass Spectrometry (GC-TOFMS). Simultaneously, we conducted a series of bioinformatics analysis of metabolites and metabolic pathways with significant differences after basic data analysis.

Results

800 signals were detected by GC–TOF mass-spectrometry and then evaluated using PCA and OPLS-DA. All the differential metabolites were listed and the related metabolic pathways were analyzed by KEGG pathway. The results showed that alanine, aspartate and glutamate metabolism had a significant change after plasma treatment. Meanwhile, d-glutamine and d-glutamate metabolism were significantly changed by CAP. Glutaminase activity was decreased after plasma treatment, which might lead to glutamine accumulation and leukemia cells death.

Conclusions

We found the above two metabolic pathways vulnerable to plasma treatment, which might result in leukemia cells death and might be the cornerstone of further exploration of plasma treatment targets.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0856-4) contains supplementary material, which is available to authorized users.

Determination of proper treatment time for in vivo blood coagulation and wound healing application by non-thermal helium plasma jet

The aim of this research was to determine the time of blood coagulation of in vivo cuts that treated by the non-thermal atmospheric pressure plasma jet. Also, the effect of different treatment times on wound healing has been studied. The non-thermal atmospheric pressure plasma jet working in helium gas has been used. The averaged treatment time of 8.6 s for in vivo cuts on the Balb/c mouse liver showed the complete blood coagulation. Also, the effect of tretament time on wound healing has been studied by applying plasma on the wounds for different times (10, 20, 30, 40 and 50 s). It was obtained from morphological analysis that the treatment groups of 30 s, 40 s and 50 s cause the wounds to be healed faster than the groups 10 s and 20 s.The histological analysis showed that in 30 s and 40 s treatment time groups, the repair process of treated wounds has been accelerated, while for 50 s group, it has not been completed, yet. The 30 s treatment time has been chosen because of imposing lower dose to living tissue. The treated wound area reduction ratios against the control wound reduction ratios for 30 s group were obtained 78%, 77% and 63% at the 3rd, 5th and 8th days, respectively.

Bacterial inactivation by plasma treated water enhanced by reactive nitrogen species

There is a growing body of literature that recognizes the importance of plasma treated water (PTW) for inactivation of microorganism. However, very little attention has been paid to the role of reactive nitrogen species (RNS) in deactivation of bacteria. The aim of this study is to explore the role of RNS in bacterial killing, and to develop a plasma system with increased sterilization efficiency. To increase the concentration of reactive oxygen and nitrogen species (RONS) in solution, we have used vapor systems (DI water/HNO₃ at different wt%) combined with plasma using N₂ as working gas. The results show that the addition of the vapor system yields higher RONS contents. Furthermore, PTW produced by N₂ + 0.5 wt% HNO₃ vapor comprises a large amount of both RNS and ROS, while PTW created by N₂ + H₂O vapor consists of a large amount of ROS, but much less RNS. Interestingly, we observed more deactivation of E. Coli with PTW created by N₂ + 0.5 wt% HNO₃ vapor plasma as compared to PTW generated by the other plasma systems. This work provides new insight into the role of RNS along with ROS for deactivation of bacteria.

CAP modifies the structure of a model protein from thermophilic bacteria: mechanisms of CAP-mediated inactivation

Cold atmospheric plasma (CAP) has great potential for sterilization in the food industry, by deactivation of thermophilic bacteria, but the underlying mechanisms are largely unknown. Therefore, we investigate here whether CAP is able to denature/modify protein from thermophilic bacteria. We focus on MTH1880 (MTH) from Methanobacterium thermoautotrophicum as model protein, which we treated with dielectric barrier discharge (DBD) plasma operating in air for 10, 15 and 20 mins. We analysed the structural changes of MTH using circular dichroism, fluorescence and NMR spectroscopy, as well as the thermal and chemical denaturation, upon CAP treatment. Additionally, we performed molecular dynamics (MD) simulations to determine the stability, flexibility and solvent accessible surface area (SASA) of both the native and oxidised protein.

High throughput image cytometry micronucleus assay to investigate the presence or absence of mutagenic effects of cold physical plasma

Promising cold physical plasma sources have been developed in the field of plasma medicine. An important prerequisite to their clinical use is lack of genotoxic effects in cells. During optimization of one or even different plasma sources for a specific application, large numbers of samples need to be analyzed. There are soft and easy-to-assess markers for genotoxic stress such as phosphorylation of histone H2AX (γH2AX) but only few tests are accredited by the OECD with regard to mutagenicity detection. The micronucleus (MN) assay is among them but often requires manual counting of many thousands of cells per sample under the microscope. A high-throughput MN assay is presented using image flow cytometry and image analysis software. A human lymphocyte cell line was treated with plasma generated with ten different feed gas conditions corresponding to distinct reactive species patterns that were investigated for their genotoxic potential. Several millions of cells were automatically analyzed by a MN quantification strategy outlined in detail in this work. Our data demonstrates the absence of newly formed MN in any feed gas condition using the atmospheric pressure plasma jet kINPen. As positive control, ionizing radiation gave a significant 5-fold increase in micronucleus frequency. Thus, this assay is suitable to assess the genotoxic potential in large sample sets of cells exposed chemical or physical agents including plasmas in an efficient, reliable, and semiautomated manner. Environ. Mol. Mutagen. 59:268-277, 2018. © 2018 Wiley Periodicals, Inc.

Low-temperature Plasma Promotes Fibroblast Proliferation in Wound Healing by ROS-activated NF-κB Signaling Pathway

Low-temperature plasma (LTP) has shown great promise in wound healing, although the underlying mechanism remains poorly understood. In the present study, an argon atmospheric pressure plasma jet was employed to treat L929 murine fibroblasts cultured in vitro and skin wounds in BALB/c mice. The in vitro analysis revealed that treatment of fibroblasts with LTP for 15 s resulted in a significant increase in cell proliferation, secretion of epidermal growth factor (EGF) and transforming growth factor-βi (TGF-βi), production of intracellular reactive oxygen species (ROS), and the percentage of cells in S phase, protein expression of phosphorylated p65 (P-p65) and cyclinD1, but a noted decrease in the protein expression of inhibitor kappa B (IκB). The in vitro experiments demonstrated that 30-s LTP treatment enhanced the number of fibroblasts and the ability of collagen synthesis, while 50-s treatment led to the opposite outcomes. These results suggested that LTP treatment promotes the fibroblast proliferation in wound healing by inducing the generation of ROS, upregulating the expression of P-p65, downregulating the expression of IκB, and activating the NF-κB signaling pathway and consequently altering cell cycle progression (increased DNA synthesis in S phage).