Cold plasma on full-thickness cutaneous wound accelerates healing through promoting inflammation, re-epithelialization and wound contraction

A combined treatment for self-traumatic chronic skin lesions associated with post-surgical neuropathic pain in a domestic cat: a pharmacological and cold atmospheric plasma approach

Cold atmospheric plasma (CAP) has been employed as a therapy against both acute and chronic skin lesions, contaminated or not, and has effects on angiogenesis and reepithelialization promoting healing. In this context, the present study aimed to evaluate the effects of a CAP jet associated with pharmacological treatment described by the 2015 AAHA/AAFP pain management guidelines and the 2022 WSAVA guidelines for the recognition, assessment, and treatment of pain, on the healing of chronic skin lesions caused by a pruritic reaction resulting from post-surgical neuropathic pain. To this end, a single CAP application was performed on a feline patient with a 6 months old recurrent contaminated cervical skin lesions along with administration of ketamine (10 µg/kg/min) following the prescription of prednisone (1 mg/kg, SID, 6 days), gabapentin (8 mg/kg, BID, 60 days) and amitriptyline (0.5 mg /kg, SID, 60 days). A single application of plasma associated with an NMDA antagonist, anti-inflammatory steroid, tricyclic antidepressant and gabapentinoid thus provided a significant improvement in the macroscopic appearance of the lesion within 10 days, and the owner reported the cessation of intense itching within the first four hours after treatment and a consequent improvement in the animal's quality of life. The medical treatment was finished almost a year since the writing of this paper, without clinical or reported recurrent signs of the condition. Therefore, we observed that single dose CAP application associated with ketamine, gabapentin, amitriptyline and prednisone leads to significant healing of chronically infected skin lesions resulting from post-surgical neuropathic pain.

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.

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.

Innovative Treatment Strategies to Accelerate Wound Healing: Trajectory and Recent Advancements

Wound healing is highly specialized dynamic multiple phase process for the repair of damaged/injured tissues through an intricate mechanism. Any failure in the normal wound healing process results in abnormal scar formation, and chronic state which is more susceptible to infections. Chronic wounds affect patients’ quality of life along with increased morbidity and mortality and are huge financial burden to healthcare systems worldwide, and thus requires specialized biomedical intensive treatment for its management. The clinical assessment and management of chronic wounds remains challenging despite the development of various therapeutic regimens owing to its painstakingly long-term treatment requirement and complex wound healing mechanism. Various conventional approaches such as cell therapy, gene therapy, growth factor delivery, wound dressings, and skin grafts etc., are being utilized for promoting wound healing in different types of wounds. However, all these abovementioned therapies are not satisfactory for all wound types, therefore, there is an urgent demand for the development of competitive therapies. Therefore, there is a pertinent requirement to develop newer and innovative treatment modalities for multipart therapeutic regimens for chronic wounds. Recent developments in advanced wound care technology includes nanotherapeutics, stem cells therapy, bioengineered skin grafts, and 3D bioprinting-based strategies for improving therapeutic outcomes with a focus on skin regeneration with minimal side effects. The main objective of this review is to provide an updated overview of progress in therapeutic options in chronic wounds healing and management over the years using next generation innovative approaches. Herein, we have discussed the skin function and anatomy, wounds and wound healing processes, followed by conventional treatment modalities for wound healing and skin regeneration. Furthermore, various emerging and innovative strategies for promoting quality wound healing such as nanotherapeutics, stem cells therapy, 3D bioprinted skin, extracellular matrix-based approaches, platelet-rich plasma-based approaches, and cold plasma treatment therapy have been discussed with their benefits and shortcomings. Finally, challenges of these innovative strategies are reviewed with a note on future prospects.

Applications of Plasma Produced with Electrical Discharges in Gases for Agriculture and Biomedicine

The use of thermal and non-thermal atmospheric pressure plasma to solve problems related to agriculture and biomedicine is the focus of this paper. Plasma in thermal equilibrium is used where heat is required. In agriculture, it is used to treat soil and land contaminated by the products of biomass, plastics, post-hospital and pharmaceutical waste combustion, and also by ecological phenomena that have recently been observed, such as droughts, floods and storms, leading to environmental pollution. In biomedical applications, thermal plasma is used in so-called indirect living tissue treatment. The sources of thermal plasma are arcs, plasma torches and microwave plasma reactors. In turn, atmospheric pressure cold (non-thermal) plasma is applied in agriculture and biomedicine where heat adversely affects technological processes. The thermodynamic imbalance of cold plasma makes it suitable for organic syntheses due its low power requirements and the possibility of conducting chemical reactions in gas at relatively low and close to ambient temperatures. It is also suitable in the treatment of living tissues and sterilisation of medical instruments made of materials that are non-resistant to high temperatures. Non-thermal and non-equilibrium discharges at atmospheric pressure that include dielectric barrier discharges (DBDs) and atmospheric pressure plasma jets (APPJs), as well as gliding arc (GAD), can be the source of cold plasma. This paper presents an overview of agriculture and soil protection problems and biomedical and health protection problems that can be solved with the aid of plasma produced with electrical discharges. In particular, agricultural processes related to water, sewage purification with ozone and with advanced oxidation processes, as well as those related to contaminated soil treatment and pest control, are presented. Among the biomedical applications of cold plasma, its antibacterial activity, wound healing, cancer treatment and dental problems are briefly discussed.

Atmospheric pressure plasma jet-mouse skin interaction: Mitigation of damages by liquid interface and gas flow control

The possible benefits of an atmospheric pressure plasma jet skin treatment have been tested in vivo on mouse skin. Many studies have been conducted in vitro on mouse skin cells, but only a few in vivo where, due to the complexity of the biological system, plasma can cause severe damages. For this reason, we investigated how kHz plasma generated in a jet that is known to inflict skin damage interacts with mouse skin and explored how we can reduce the skin damage. First, the focus was on exploring plasma effects on skin damage formation with different plasma gases and jet inclinations. The results pointed to the perpendicular orientation of a He plasma jet as the most promising condition with the least skin damage. Then, the skin damage caused by a He plasma jet was explored, focusing on damage mitigation with different liquid interfaces applied to the treatment site, adding N₂ to the gas mixture, or alternating the gas flow dynamics by elongating the jet's glass orifice with a funnel. All these mitigations proved highly efficient, but the utmost benefits for skin damage reduction were connected to skin temperature reduction, the reduction in reactive oxygen species (ROS), and the increase in reactive nitrogen species (RNS).

Emerging treatment strategies in wound care

Wound healing is a complex process in tissue regeneration through which the body responds to the dissipated cells as a result of any kind of severe injury. Diabetic and non-healing wounds are considered an unmet clinical need. Currently, different strategic approaches are widely used in the treatment of acute and chronic wounds which include, but are not limited to, tissue transplantation, cell therapy and wound dressings, and the use of an instrument. A large number of literatures have been published on this topic; however, the most effective clinical treatment remains a challenge. The wound dressing involves the use of a scaffold, usually using biomaterials for the delivery of medication, autologous stem cells, or growth factors from the blood. Antibacterial and anti-inflammatory drugs are also used to stop the infection as well as accelerate wound healing. With an increase in the ageing population leading to diabetes and associated cutaneous wounds, there is a great need to improve the current treatment strategies. This research critically reviews the current advancement in the therapeutic and clinical approaches for wound healing and tissue regeneration. The results of recent clinical trials suggest that the use of modern dressings and skin substitutes is the easiest, most accessible, and most cost-effective way to treat chronic wounds with advances in materials science such as graphene as 3D scaffold and biomolecules hold significant promise. The annual market value for successful wound treatment exceeds over $50 billion US dollars, and this will encourage industries as well as academics to investigate the application of emerging smart materials for modern dressings and skin substitutes for wound therapy.

The Anti-Fibrotic Effect of Cold Atmospheric Plasma on Localized Scleroderma In Vitro and In Vivo

Cold Atmospheric Plasma (CAP) has shown promising results in the treatment of various skin diseases. The therapeutic effect of CAP on localized scleroderma (LS), however, has not yet been evaluated. We investigated the effects of CAP on LS by comparing human normal fibroblasts (hNF), human TGF-β-activated fibroblasts (hAF), and human localized scleroderma-derived fibroblasts (hLSF) after direct CAP treatment, co-cultured with plasma-treated human epidermal keratinocytes (hEK) and with an experimental murine model of scleroderma. In hAF and hLSF, 2 min CAP treatment with the MicroPlaSterβ^® plasma torch did not affect pro-fibrotic gene expression of alpha smooth muscle actin, fibroblast activating protein, and collagen type I, however, it promoted re-expression of matrix metalloproteinase 1. Functionally, CAP treatment reduced cell migration and stress fiber formation in hAF and hLSF. The relevance of CAP treatment was confirmed in an in vivo model of bleomycin-induced dermal fibrosis. In this model, CAP-treated mice showed significantly reduced dermal thickness and collagen deposition as well as a decrease in both alpha smooth muscle actin-positive myofibroblasts and CD68-positive macrophages in the affected skin in comparison to untreated fibrotic tissue. In conclusion, this study provides the first evidence for the successful use of CAP for treating LS and may be the basis for clinical trials including patients with LS.

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.

Effects of cold physical plasma on oral lichen planus: An in vitro study (Effects of CAP on OLP)

OBJECTIVES

In the search for more effective and safe treatment avenues, we investigated cold physical plasma as a new treatment modality for therapy of oral lichen planus (OLP).

MATERIAL AND METHODS

Healthy and diseased human mucosal tissue samples with a size of 3 mm in diameter obtained from OLP patients were subjected to plasma treatment ex vivo or were left untreated. Tissue sections were quantified for immune-infiltration of CD4+ , CD8+ , CD45RA+ , and CD45R0+ T cells. Moreover, the tissues' inflammatory profile was assessed by analyzing 12 different cytokines in the surrounding media.

RESULTS

A significantly increased infiltrate of CD8+ and CD45-R0+ T cells was detected in OLP tissue samples when compared to healthy tissue. A higher concentration of interleukin (IL) 1β, IL6, IL8, and granulocyte macrophage-colony stimulating factor (GM-CMF) was detected in OLP samples compared to healthy mucosal tissue. For all cytokines and chemokines investigated, 23 out of 24 comparisons showed a decrease in tendency (significant for IL1β, IL2, IL10, and GM-CSF) in response to plasma treatment. In ex vivo-treated tissue, a decrease of T-cell infiltrate in OLP lesions compared with healthy tissue was observed.

CONCLUSION

Our findings suggest cold physical plasma can be a promising therapeutic option for OLP that requires further validation in vivo.

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.

The influence of a biofilm-dispersing wound gel on the wound healing process

Topical antimicrobials that reduce the bacterial bioburden within a chronically‐infected wound may have helpful or harmful effects on the healing process. We used murine models of full‐thickness skin wounds to determine the effects of the novel biofilm‐dispersing wound gel (BDWG) and its gel base on the healing of uninfected wounds. The rate of wound closure over 19 days was comparable among the BDWG‐treated (BT) wounds and the controls. Compared with the controls, histology of the BT wounds showed formation of a stable blood clot at day 1, more neovascularisation and reepithelialisation at day 3, and more organised healing at day 7. Fluorescence‐activated cell sorting analysis showed a lower percentage of neutrophils in wounded tissues of the BT group at days 1 and 3, and significantly more M2 macrophages at day 3. Levels of proinflammatory cytokines and chemokines were increased over the uninjured baseline within the wounds of all treatment groups but the levels were significantly lower in the BT group at day 1, modulating the inflammatory response. Our results suggest that BDWG does not interfere with the wound healing process and may enhance it by lowering inflammation and allowing transition to the proliferative stage of wound healing by day 3.

Could cold plasma act synergistically with allogeneic mesenchymal stem cells to improve wound skin regeneration in a large size animal model?

Skin wound healing may sometimes lead to open sores that persist for long periods and expensive hospitalization is needed. Among different kinds of therapeutic innovative approaches, mesenchymal stem cells (MSCs) and low-temperature atmospheric pressure cold plasma (ionized gas) have been recently tested to improve this regenerative process. To optimize wound healing the present study intended to combine, for the first time, these two novel approaches in a large size animal wound healing model with the aim of assessing the putative dual beneficial effects. Based on clinical, histopathological, and molecular results a synergistic action in a second intention healing wound in sheep has been observed. Experimental wounds treated with cold plasma and MSCs showed a slower but more effective healing compared to the single treatment, as observed in previous studies. The combined treatment improved the correct development of skin appendages and structural proteins of the dermis showing the potential of the dual combination as a safe and effective tool for skin regeneration in the veterinary clinical field.

Plasma-activated interfaces for biomedical engineering

As an important phenomenon to monitor disease development, cell signaling usually takes place at the interface between organisms/cells or between organisms/cells and abiotic materials. Therefore, finding a strategy to build the specific biomedical interfaces will help regulate information transmission and produce better therapeutic results to benefit patients. In the past decades, plasmas containing energetic and active species have been employed to construct various interfaces to meet biomedical demands such as bacteria inactivation, tissue regeneration, cancer therapy, and so on. Based on the potent functions of plasma modified surfaces, this mini-review is aimed to summarize the state-of-art plasma-activated interfaces and provide guidance to researchers to select the proper plasma and processing conditions to design and prepare interfaces with the optimal biological and related functions. After a brief introduction, plasma-activated interfaces are described and categorized according to different criteria including direct plasma-cells interfaces and indirect plasma-material-cells interfaces and recent research activities on the application of plasma-activated interfaces are described. The authors hope that this mini-review will spur interdisciplinary research efforts in this important area and expedite associated clinical applications.

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The Interfaces between organisms/cells and abiotic materials are crucial for cell signaling.

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Plasmas containing energetic and active species are potent tool to construct biomedical interfaces.

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The objective here is to summarize recent plasma-activated interfaces to spur interdisciplinary efforts for clinical applications.

Plasma medicine: Opportunities for nanotechnology in a digital age

Advances in digital technologies have opened new opportunities for creating more reliable, time- and cost-effective, safer and mobile methods of diagnosing, managing and treating diseases. A few examples of advanced nano- and digital technologies are already FDA-approved for diagnosing and treating diseases. Plasma treatment is still emerging as a new healthcare technology, but it is showing a strong potential for treatment of many diseases including cancers and antimicrobial-resistant infections, with little or no adverse side effects. Here, we argue that with the ever-increasing complex healthcare challenges facing communities, including the ongoing COVID-19 pandemic, it is critical to consider combining unique properties of emerging healthcare technologies into a single multimodal treatment modality that could lead to unprecedented healthcare benefits. In this article, we focus on the healthcare opportunities created by establishing a nexus between plasma, nano- and digital technologies. We argue that the combination of plasma, nano- and digital technologies into a single multimodal healthcare package may significantly improve patient outcomes and comfort, and reduce the economic burden on community healthcare, as well as alleviate many problems related to overcrowded healthcare systems.

Utility of Reactive Species Generation in Plasma Medicine for Neuronal Development

Reactive oxygen species (ROS) are critical signaling molecules for neuronal physiology that stimulate growth and development and play vital roles in several pathways when in a balanced state, but they cause neurodegeneration when unbalanced. As ROS levels above a certain threshold cause the activation of the autophagy system, moderate levels of ROS can be used as treatment strategies. Currently, such treatments are used together with low-level laser or photodynamic therapies, photo-bio modulation, or infrared treatments, in different chronic diseases but not in the treatment of neurodegeneration. Recently, non-thermal plasma has been successfully used in biomedical applications and treatments, and beneficial effects such as differentiation, cell growth, and proliferation, stimulation of ROS based pathways have been observed. Besides the activation of a wide range of biological signaling pathways by generating ROS, plasma application can be an effective treatment in neuronal regeneration, as well as in neuronal diseases. In this review, we summarize the generation and role of ROS in neurons and provide critical insights into their potential benefits on neurons. We also discuss the underlying mechanisms of ROS on neuronal development. Regarding clinical applications, we focus on ROS-based neuronal growth and regeneration strategies and in the usage of non-thermal plasma in neuronal and CNS injury treatments.

Evaluation of efficacy of non-thermal atmospheric pressure plasma in treatment of periodontitis: a randomized controlled clinical trial

OBJECTIVES

In this clinical study, we aim to evaluate the effectiveness of non-thermal atmospheric pressure plasma (NAPP), which is a novel procedure used in periodontal pocket decontamination adjunctive to non-surgical periodontal treatment (NSPT).

METHODS

The study included 25 systemically healthy periodontitis patients. In the split-mouth design, NAPP application into the pockets, in addition to NSPT, was performed. Clinical periodontal data, gingival crevicular fluid, and subgingival plaque samples of patients were taken before and during the first and third months of treatment. Biochemical assays were conducted using enzyme-linked immunosorbent assay. Analysis of bacteria was performed with polymerase chain reaction method.

RESULTS

There was more clinical attachment level (CAL) gain in the 3rd month in the test group (deep pockets: 3.90 mm, pockets ≥ 5 mm: 2.72 mm) compared to the control group (deep pockets: 3.40 mm, pockets ≥ 5 mm: 2.58 mm) (p < 0.05), but no significant difference between groups in CAL. Clinical periodontal parameters improved in both study groups (p < 0.05). However, the gingival index (GI) and the bleeding on probing (BOP) rate decreased more in the test group (GI: 0.55, BOP: 9.48%, and GI: 0.38, BOP: 8.46% in the 1st and 3rd months, respectively) compared to the control group (GI: 0.68, BOP: 13.43%, and GI: 0.52, BOP: 14.58%) (p < 0.05). In addition, there was no significant difference in probing depth and biochemical markers between groups (p > 0.05). It was observed that NAPP reduced the number of bacteria more than the control group in the 1st and 3rd months.

CONCLUSIONS

It was seen that the single-time NAPP application concurrent with NSPT provided additional CAL gain, elimination of putative periodontopathogens and reduced their recolonization. Longitudinal studies with larger population and longer time are required.

CLINICAL RELEVANCE

NSPT is an effective method for the treatment of periodontitis but bacteria recolonization that causes recurrence of the periodontal disease occurs within a short period. NAPP can reduce the recurrence of periodontal disease by providing better bacterial elimination and should, therefore, be used in maintenance of periodontitis.

The effect of nitrogen plasma on the skin and hair follicles: a possible promising future for the treatment of alopecia

Nowadays, there is a great attention to the plasma applications in medicine. Not only does cold atmospheric pressure plasma provide a therapeutic opportunity to control redox-based processes, it is also an innovative method in rejuvenation. Given the current interest in new methods of rejuvenation, we aimed to introduce a novel pulsed nitrogen plasma torch with potential use in rejuvenation. We investigated production of reactive species at different pulse energy by spectroscopy and also measured nitric oxide and O₂ concentration and evaluated the flame temperature. Fifteen Wistar rats were divided into three groups based on the applied energy settings; the skin of the animals was processed with plasma. For quantitative evaluation of dermis, epidermis and hair follicles (to confirm the effects of this technique on rejuvenation), skin biopsies were taken from both unexposed and treated areas. The spectroscopy results showed the presence of nitric oxide in plasma and the concentration was suitable for dermatological applications. A significant increase was observed in epidermal thickness, fibroblast cell proliferation and collagenesis (P < 0.05). Interestingly, plasma led to a temporary increase in the diameter of primary and secondary hair follicles compared to the controls. The results confirmed the positive effects of this pulsed nitrogen plasma torch on rejuvenation and also revealed a new possible aspect of cold plasma; its effect on hair follicles as a promising area in the treatment of alopecia that requires further clinical and molecular studies.

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.

Cold Argon Plasma as Adjuvant Tumour Therapy on Progressive Head and Neck Cancer: A Preclinical Study

Investigating cold argon plasma (CAP) for medical applications is a rapidly growing, innovative field of research. The controllable supply of reactive oxygen and nitrogen species through CAP has the potential for utilization in tumour treatment. Maxillofacial surgery is limited if tumours grow on vital structures such as the arteria carotis. Here CAP could be considered as an option for adjuvant intraoperative tumour therapy especially in the case of squamous cell carcinoma of the head and neck. Further preclinical research is necessary to investigate the efficacy of this technology for future clinical applications in cancer treatment. Initially, a variety of in vitro assays was performed on two cell lines that served as surrogate for the squamous cell carcinoma (SCC) and healthy tissue, respectively. Cell viability, motility and the activation of apoptosis in SCC cells (HNO97) was compared with those in normal HaCaT keratinocytes. In addition, induction of apoptosis in ex vivo CAP treated human tissue biopsies of patients with tumours of the head and neck was monitored and compared to healthy control tissue of the same patient. In response to CAP treatment, normal HaCaT keratinocytes differed significantly from their malignant counterpart HNO97 cells in cell motility only whereas cell viability remained similar. Moreover, CAP treatment of tumour tissue induced more apoptotic cells than in healthy tissue that was accompanied by elevated extracellular cytochrome c levels. This study promotes a future role of CAP as an adjuvant intraoperative tumour therapy option in the treatment of head and neck cancer. Moreover, patient-derived tissue explants complement in vitro examinations in a meaningful way to reflect an antitumoral role of CAP.

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.

Prevention of Peritoneal Adhesions by Non-Thermal Dielectric Barrier Discharge Plasma Treatment on Mouse Model: A Proof of Concept Study

Purposes: Formation of peritoneal adhesions is a common consequence of abdominopelvic surgeries and remarkably increases the mortality and morbidity. Moreover, peritoneal adhesions linked to chronic abdominopelvic pain and infertility in women. Various attempts for prevention of peritoneal adhesions were reported. However, these methods either remain insufficient to prevent formation of peritoneal adhesions or carry some practical limitations and thus, there is a need for novel techniques that could effectively decrease the formation of peritoneal adhesions. The aim of the present prospective, randomized, controlled, and single blinded study was to evaluate the effect of non-thermal atmospheric plasma (NTAP) treatment on prevention of peritoneal adhesions. Materials and Methods: Sixteen male CD-1 mice were randomly divided into two groups: control and plasma. Excisional and abrasion adhesion models were generated on the peritoneal side wall and cecum, respectively. Ten days after creating adhesion models, mice were sacrificed and adhesion formations were evaluated macroscopically using Knightly's and Linsky's grading systems to assess the intensity and extent of adhesions, respectively. Zühlke's grading system was used for microscopic assessment of adhesions. Results: The mean scores for peritoneum and cecum in control group according to Knightly's grading system were determined as 3.3 and 2.6, respectively. In NTAP-treated group, Knightly's score was determined as 1.6 and 0.5 for peritoneum and cecum, respectively. NTAP treatment reduced Linsky's score from 3.8 to 1.3 and 2.1 to 1.1 on peritoneum and cecum. Finally, in microscopic evaluation, NTAP treatment reduced Zühlke's score from 3.4 to 1.5 and 2.6 to 1.3 for peritoneum and cecum, respectively. Conclusions: The results of the present proof of concept study suggest that NTAP could be a novel method to reduce and/or prevent the formation of peritoneal adhesions after abdominopelvic surgeries.

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.

Long-lived and short-lived reactive species produced by a cold atmospheric pressure plasma jet for the inactivation of Pseudomonas aeruginosa and Staphylococcus aureus

Different chemical pathways leading to the inactivation of Pseudomonas aeruginosa and Staphylococcus aureus by a cold atmospheric pressure plasma jet (APPJ) in buffered and non-buffered solutions are reported. As APPJs produce a complex mixture of reactive species in solution, a comprehensive set of diagnostics were used to assess the liquid phase chemistry. This includes absorption and electron paramagnetic resonance spectroscopy in addition to a scavenger study to assess the relative importance of the various plasma produced species involved in the inactivation of bacteria. Different modes of inactivation of bacteria were found for the same plasma source depending on the solution and the plasma feed gas. The inactivation of bacteria in saline is due to the production of short-lived species in the case of argon plasma when the plasma touches the liquid. Long-lived species (ClO^-) formed by the abundant amount of O^. radicals produced by the plasmas played a dominant role in the case of Ar + 1% O₂ and Ar + 1% air plasmas when the plasma is not in direct contact with the liquid. Inactivation of bacteria in distilled water was found to be due to the generation of short-lived species: O^. &O₂^.- for Ar + 1% O₂ plasma and O₂^.- (and ^.OH in absence of saline) for Ar plasma.

Wound Healing in Streptozotocin-Induced Diabetic Rats Using Atmospheric-Pressure Argon Plasma Jet

In this study, we used an argon-based round atmospheric-pressure plasma jet (APPJ) for enhancing wound healing in streptozotocin (STZ) induced diabetic rats. The APPJ was characterized by optical emission spectroscopy. We induced Type 1 and Type 2 diabetes in rats with different amounts of STZ combined with normal and high-fat diets, respectively. The wound area ratio of all the plasma-treated normal and diabetic groups was greatly reduced (up to 30%) compared with that of the untreated groups during healing. Histological analysis revealed faster re-epithelialization, collagen deposition, less inflammation, and a complete skin structure in the plasma-treated groups was found as compared with the untreated control groups. In addition, the new blood vessels of plasma-treated tissues decreased more than untreated tissues in the middle (Day 14) and late (Day 21) stages of wound healing. The plasma-treated wounds demonstrated more transforming growth factor beta (TGF-β) expression in the early stage (Day 7), whereas they decreased in the middle and late stages of wound healing. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) increased after plasma treatment. In addition, plasma-treated water had a higher concentration of hydrogen peroxide, nitrite and nitrate when the plasma treatment time was longer. In summary, the proposed argon APPJ based on the current study could be a potential tool for treating diabetic wounds.

In vivo study of non-invasive effects of non-thermal plasma in pressure ulcer treatment

According to high incidence and prevalence of pressure ulcers worldwide, the purpose of this study is using of non-thermal atmospheric plasma as a novel therapy for pressure ulcers. Cold plasma was produced by applying a high-voltage (5 kV) and high-frequency (25 kHz), to helium gas. Under general anesthesia and sterile conditions, two circular magnets were used to create pressure ulcers on the dorsal skin of adult rats. The wounds were divided randomly into control and plasma-treated groups. Animals in the plasma-treated group received plasma radiation for 5 days, each day 3 times and every time 60 s. Mechanical assays were performed to determine plasma effects on the mechanical strength of the repaired tissue. The results showed that mechanical strength of repaired wound in the plasma-treated group was significantly higher than that in the control group (p < 0.05). In addition, evidence from histological studies indicates a significantly accelerated wound re-epithelialization in comparison with the control group; angiogenesis and fibrosis (collagen synthesis) were also significantly increased and the inflammation phase of wound healing was shorter in the plasma-treated group. The plasma treatment also resulted in significant wound contraction and acceleration of wound healing. The findings of present study indicate the effects of cold plasma on pressure ulcer treatment.

A cold plasma jet accelerates wound healing in a murine model of full-thickness skin wounds

Cold plasma has been successfully applied in several fields of medicine that require, for example, pathogen inactivation, implant functionalization or alteration of cellular activity. Previous studies have provided evidence that plasma supports the healing of wounds owing to its beneficial mixtures of reactive species and modulation of inflammation in cells and tissues. To investigate the wound healing activity of an atmospheric pressure plasma jet in vivo, we examined the cold plasma's efficacy on dermal regeneration in a murine model of dermal full-thickness ear wound. Over 14 days, female mice received daily plasma treatment. Quantitative analysis by transmitted light microscopy demonstrated a significantly accelerated wound re-epithelialization at days 3-9 in comparison with untreated controls. In vitro, cold plasma altered keratinocyte and fibroblast migration, while both cell types showed significant stimulation resulting in accelerated closure of gaps in scratch assays. This plasma effect correlated with the downregulation of the gap junctional protein connexin 43 which is thought to be important in the regulation of wound healing. In addition, plasma induced profound changes in adherence junctions and cytoskeletal dynamics as shown by downregulation of E-cadherin and several integrins as well as actin reorganization. Our results theorize cold plasma to be a beneficial treatment option supplementing existing wound therapies.

Low temperature plasma induces angiogenic growth factor via up-regulating hypoxia-inducible factor 1α in human dermal fibroblasts

Numerous studies on the application of low temperature plasma (LTP) have produced impressive results, including antimicrobial, antitumor, and wound healing effects. Although LTP research has branched out to include medical applications, the detailed effects and working mechanisms of LTP on wound healing have not been fully investigated. Here, we investigated the potential effect of inducing growth factor after exposure to LTP and demonstrated the increased expression of angiogenic growth factor mediated by LTP-induced HIF1α expression in primary cultured human dermal fibroblasts. In cell viability assays, fibroblast viability was reduced 6 h and 24 h after LTP treatment for only 5 min, and pre-treating with NAC, a ROS scavenger, prevented cell loss. Fibroblast migration significantly increased at 6 h and 24 h in scratch wound healing assays, the expression of cytokines significantly changed, and regulatory growth factors were induced at 6 h and 24 h after exposure to LTP in RT-PCR or ELISAs. Specifically, LTP treatment significantly induced the expression of HIF1α, an upstream regulator of angiogenesis. Pre-treatment with the inhibitor CAY10585 abolished HIF1α expression and prevented LTP-induced angiogenic growth factor production according to immunoblotting, immunocytochemistry, and ELISA results. Taken together, our results provide information on the molecular mechanism by which LTP application may promote angiogenesis and will aid in developing methods to improve wound healing.

Novel design of high voltage pulse source for efficient dielectric barrier discharge generation by using silicon diodes for alternating current

This work focuses on design, construction, and optimization of configuration of a novel high voltage pulse power source for large-scale dielectric barrier discharge (DBD) generation. The pulses were generated by using the high-speed switching characteristic of an inexpensive device called silicon diodes for alternating current and the self-terminated characteristic of DBD. The operation started to be powered by a primary DC low voltage power supply flexibly equipped with a commercial DC power supply, or a battery, or DC output of an independent photovoltaic system without transformer employment. This flexible connection to different types of primary power supply could provide a promising solution for the application of DBD, especially in the area without power grid connection. The simple modular structure, non-control requirement, transformer elimination, and a minimum number of levels in voltage conversion could lead to a reduction in size, weight, simple maintenance, low cost of installation, and high scalability of a DBD generator. The performance of this pulse source has been validated by a load of resistor. A good agreement between theoretically estimated and experimentally measured responses has been achieved. The pulse source has also been successfully applied for an efficient DBD plasma generation.

Antibacterial efficacy of a novel plasma reactor without an applied gas flow against methicillin resistant Staphylococcus aureus on diverse surfaces

The use of nonthermal plasma in the clinic has gained recent interest, as the need for alternative or supplementary strategies are necessary for preventing multi-drug resistant infections. The purpose of this study was to evaluate the antibacterial efficacy of a novel plasma reactor based on a high current version of sliding discharge and operated by nanosecond voltage pulses without an applied gas flow. This modification is advantageous for both portability and convenience. Bacterial inactivation was determined within a chamber by direct quantification of colony Jing units. Plasma exposure significantly inhibited the growth of Escherichia coli and Staphylococcus epidermidis following a 1-min application (p<0.001). S. epidermidis was more susceptible to the plasma after a 5-min exposure compared to E. coli. Temperature and pH measurements taken immediately before and after plasma exposure determined neither heat nor pH changes play a role in bacterial inactivation. Because of the notable effect on S. epidermidis, the effect of plasma exposure on several isolates and strains of the related opportunistic pathogen Staphylococcus aureus was quantified. While S. aureus isolates and strains were efficiently inactivated on an agar surface, subsequent testing on other clinically relevant surfaces demonstrated that the inactivation level, although significant, was reduced. This reduction appeared to depend on both the surface texture and the surface moisture content. These findings suggest this novel plasma source lacking an applied gas flow has potential application for surface bacterial decontamination.

The repetitive use of non-thermal dielectric barrier discharge plasma boosts cutaneous microcirculatory effects

BACKGROUND

Non-thermal atmospheric plasma has proven its benefits in sterilization, cauterization and even in cancer reduction. Furthermore, physical plasma generated by dielectric barrier discharge (DBD) promotes wound healing in vivo and angiogenesis in vitro. Moreover, cutaneous blood flow and oxygen saturation can be improved in human skin. These effects are mostly explained by reactive oxygen species (ROS), but electric fields, currents and ultraviolet radiation may also have an impact on cells in the treated area. Usually, single session application is used. The aim of this study was to evaluate the effects of the repetitive use of cold atmospheric plasma (rCAP) on cutaneous microcirculation.

HYPOTHESIS

The repetitive use of non-thermal atmospheric plasma boosts cutaneous microcirculation effects.

METHODS

Microcirculatory data was assessed at a defined skin area of the radial forearm of 20 healthy volunteers (17 males, 3 females; mean age 39.1±14.8years; BMI 26.4±4.6kg/m(2)). Microcirculatory measurements were performed under standardized conditions using a combined laser Doppler and photospectrometry system. After baseline measurement, CAP was applied by a DBD plasma device for 90s and cutaneous microcirculation was assessed for 10min. Afterwards, a second session of CAP application was performed and microcirculation was measured for another 10min. Then, the third application was made and another 20min of microcirculatory parameters were assessed.

RESULTS

Tissue oxygen saturation and postcapillary venous filling pressure significantly increased after the first application and returned to baseline values within 10min after treatment. After the second and third applications, both parameters increased significantly vs. baseline until the end of the 40-minute measuring period. Cutaneous blood flow was significantly enhanced for 1min after the first application, with no significant differences found during the remainder of the observation period. The second application improved and prolonged the effect significantly until 7min and the third application until 13min.

CONCLUSION

These data indicate that the repetitive use of non-thermal atmospheric plasma boosts and prolongs cutaneous microcirculation and might therefore be a potential tool to promote wound healing.

Improvement of cutaneous microcirculation by cold atmospheric plasma (CAP): Results of a controlled, prospective cohort study

BACKGROUND

Cold atmospheric plasma (CAP) has proven its benefits in the reduction of various bacteria and fungi in both in vitro and in vivo studies. Moreover, CAP generated by dielectric barrier discharge (DBD) promoted wound healing in vivo. Charged particles, chemically reactive species (such as O3, OH, H2O2, O, NxOy), ultraviolet radiation (UV-A and UV-B), strong oscillating electric fields as well as weak electric currents are produced by DBD operated in air. However, wound healing is a complex process, depending on nutrient and oxygen supply via cutaneous blood circulation. Therefore, this study examined the effects of CAP on cutaneous microcirculation in a prospective cohort setting.

HYPOTHESIS

Cold atmospheric plasma application enhances cutaneous microcirculation.

METHODS

Microcirculatory data of 20 healthy subjects (11 males, 9 females; mean age 35.2 ± 13.8 years; BMI 24.3 ± 3.1 kg/m(2)) were recorded continuously at a defined skin area at the radial forearm. Under standardized conditions, microcirculatory measurements were performed using a combined laser Doppler and photospectrometry system. After baseline measurement, CAP was applied by a DBD plasma device for 90 s to the same defined skin area of 22.5 cm(2). Immediately after the application cutaneous microcirculation was assessed for 30 min at the same site.

RESULTS

After CAP application, tissue oxygen saturation immediately increased by 24% (63.8 ± 13.8% from 51.4 ± 13.2% at baseline, p<0.001) and stayed significantly elevated for 8 min. Cutaneous blood flow increased by 73% (41.0 ± 31.2 AU from 23.7 ± 20.8 AU at baseline, p<0.001) and remained upregulated for 11 min. Furthermore, cutaneous blood flow showed two peaks at 14 (29.8 ± 25.0 AU, p=0.049) and 19 min (29.8 ± 22.6 AU, p=0.048) after treatment. Postcapillary venous filling pressure continuously increased, but showed no significant change vs. baseline in the non-specific BMI group. Subgroup analysis revealed that tissue oxygen saturation, postcapillary venous filling pressure and blood flow increased more in case of a lower BMI.

CONCLUSION

CAP increases cutaneous tissue oxygen saturation and capillary blood flow at the radial forearm of healthy volunteers. These results support recently published data on wound healing after CAP treatment. However, further studies are needed to determine if this treatment can improve the reduced microcirculation in diabetic foot ulcers. Moreover, repetitive application protocols have to be compared with a single session treatment approach.

On the effect of serum on the transport of reactive oxygen species across phospholipid membranes

The transport of plasma generated reactive oxygen species (ROS) across a simple phospholipid membrane mimic of a (real) cell was investigated. Experiments were performed in cell culture media (Dulbecco's modified Eagle's medium, DMEM), with and without 10% serum. A (broad spectrum) ROS reporter dye, 2,7-dichlorodihydrofluorescein (DCFH), was used to detect the generation of ROS by a helium (He) plasma jet in DMEM using free DCFH and with DCFH encapsulated inside phospholipid membrane vesicles dispersed in DMEM. The authors focus on the concentration and on the relative rates (arbitrary units) for oxidation of DCFH [or the appearance of the oxidized product 2,7-dichlorofluorescein (DCF)] both in solution and within vesicles. In the first 1 h following plasma exposure, the concentration of free DCF in DMEM was ~15× greater in the presence of serum (cf. to the serum-free DMEM control). The DCF in vesicles was ~2× greater in DMEM containing serum compared to the serum-free DMEM control. These data show that serum enhances plasma ROS generation in DMEM. As expected, the role of the phospholipid membrane was to reduce the rate of oxidation of the encapsulated DCFH (with and without serum). And the efficiency of ROS transport into vesicles was lower in DMEM containing serum (at 4% efficiency) when compared to serum-free DMEM (at 32% efficiency). After 1 h, the rate of DCFH oxidation was found to have significantly reduced. Based upon a synthesis of these data with results from the open literature, the authors speculate on how the components of biological fluid and cellular membranes might affect the kinetics of consumption of plasma generated ROS.