Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species

Enhanced Fat Graft Viability and Remodeling Using a Helium-based Radiofrequency Device to Prepare the Recipient Site

BACKGROUND

Improvements to autologous fat grafting for soft tissue augmentation are needed to overcome the unpredictable volume retention. Approaches such as fat harvesting and processing, injection technique, preparation of the recipient site, and supplemental biologics are topics of ongoing research. Here, an energy-based device was investigated as a stimulatory tool for recipient site preparation for improving fat graft retention.

OBJECTIVE

The objective was to measure the stimulatory responses in fat grafts after 4 weeks when using a helium-based radiofrequency device to pretreat the recipient tissue.

METHODS

Using an autologous fat grafting mouse model, the inguinal fat pad was grafted in a small cranial pocket after either a saline injection alone (control) or a saline injection followed by pretreatment (treated). The fat pad was resected after 4 weeks, sectioned and stained with immunofluorescence markers to investigate tissue remodeling.

RESULTS

Pretreatment resulted in higher viability of adipocytes, a higher concentration of viable ASCs in areas of adipose tissue regeneration, and localized macrophages in the areas of regeneration when compared to the control. There was no observable difference in vascularity or angiogenesis. The staining for ASCs was higher in the pretreated group in comparison with the control group (5.0% vs. 3.3%, p=0.36) when using a pixel classifier in QuPath in the viable adipose tissue regions.

CONCLUSIONS

The use of a helium-based radiofrequency device as a pretreatment tool appears to increase the viability of the adipose tissue likely due to higher concentration of ASCs. The apparent increase in viable ASCs may be due to enhanced proliferation or paracrine recruitment of these cells in response to the helium-based radiofrequency treatment.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 . Bullet List of Important Points: Pretreatment of the fat graft recipient site increases the viability of the adipose tissue after 4 weeks in comparison with the control grafts. The increased viability is likely due to the observed increase in adipose-derived stem cells in the pretreated group. Pretreatment enhanced the adipose tissue remodeling as colocalization of adipose-derived stem cells and macrophages showed an active remodeling, whereas the control group exhibited more necrotic and fibrotic tissue.

Applications of cold atmospheric plasma in immune-mediated inflammatory diseases via redox homeostasis: evidence and prospects

As a representative technology in plasma medicine, cold atmospheric plasma (CAP) has beneficial outcomes in surface disinfection, wound repair, tissue regeneration, solid tumor therapy. Impact on immune response and inflammatory conditions was also observed in the process of CAP treatment. Relevant literatures were collected to assess efficacy and summarize possible mechanisms of the innovation. CAP mediates alteration in local immune microenvironment mainly through two ways. One is to down-regulate the expression level of several cytokines, impeding further conduction of immune or inflammatory signals. Intervening the functional phenotype of cells through different degree of oxidative stress is the other approach to manage the immune-mediated inflammatory disorders. A series of preclinical and clinical studies confirmed the therapeutic effect and side effects free of CAP. Moreover, several suggestions proposed in this manuscript might help to find directions for future investigation.

Cold Atmospheric Pressure Plasma: A Growing Paradigm in Diabetic Wound Healing-Mechanism and Clinical Significance

Diabetes is one of the most significant causes of death all over the world. This illness, due to abnormal blood glucose levels, leads to impaired wound healing and, as a result, foot ulcers. These ulcers cannot heal quickly in diabetic patients and may finally result in amputation. In recent years, different research has been conducted to heal diabetic foot ulcers: one of them is using cold atmospheric pressure plasma. Nowadays, cold atmospheric pressure plasma is highly regarded in medicine because of its positive effects and lack of side effects. These conditions have caused plasma to be considered a promising technology in medicine and especially diabetic wound healing because studies show that it can heal chronic wounds that are resistant to standard treatments. The positive effects of plasma are due to different reactive species, UV radiation, and electromagnetic fields. This work reviews ongoing cold atmospheric pressure plasma improvements in diabetic wound healing. It shows that plasma can be a promising tool in treating chronic wounds, including ones resulting from diabetes.

A Meaningful Attempt: Applying Dielectric Barrier Discharge Plasma to Induce Polarization of Macrophages

Macrophage polarization plays an important role in many macrophage-related diseases. This study was designed to preliminarily explore the effects of dielectric barrier discharge (DBD) plasma on the polarization direction and cell activity of macrophages with different phenotypes (ie, M0, M1, and M2). The M1 macrophage marker inducible nitric oxide synthase (iNOS) and M2 macrophage marker cluster of differentiation 206 (CD206) were detected by western blot (WB). The effects of DBD plasma on macrophage viability were analyzed by using a cell counting kit-8 detection kit. M0, M1, and M2 macrophages exhibited a decrease in iNOS expression and an increase in CD206 expression after the DBD plasma intervention. Additionally, the decrease in macrophage viability remained non-significant after initiating the intervention. DBD plasma can promote the transformation of M0 and M1 macrophages to M2 macrophages, and can further enhance the expression of the M2 macrophage phenotype marker CD206. Our study not only demonstrates the potential therapeutic value of DBD plasma for macrophage-related diseases, but it also provides a new direction for research to improve the treatment of macrophage-related diseases. © 2023 Bioelectromagnetics Society.

Gas Flow-Dependent Modification of Plasma Chemistry in μAPP Jet-Generated Cold Atmospheric Plasma and Its Impact on Human Skin Fibroblasts

The micro-scaled Atmospheric Pressure Plasma Jet (µAPPJ) is operated with low carrier gas flows (0.25-1.4 slm), preventing excessive dehydration and osmotic effects in the exposed area. A higher yield of reactive oxygen or nitrogen species (ROS or RNS) in the µAAPJ-generated plasmas (CAP) was achieved, due to atmospheric impurities in the working gas. With CAPs generated at different gas flows, we characterized their impact on physical/chemical changes of buffers and on biological parameters of human skin fibroblasts (hsFB). CAP treatments of buffer at 0.25 slm led to increased concentrations of nitrate (~352 µM), hydrogen peroxide (H₂O₂; ~124 µM) and nitrite (~161 µM). With 1.40 slm, significantly lower concentrations of nitrate (~10 µM) and nitrite (~44 µM) but a strongly increased H₂O₂ concentration (~1265 µM) was achieved. CAP-induced toxicity of hsFB cultures correlated with the accumulated H₂O₂ concentrations (20% at 0.25 slm vs. ~49% at 1.40 slm). Adverse biological consequences of CAP exposure could be reversed by exogenously applied catalase. Due to the possibility of being able to influence the plasma chemistry solely by modulating the gas flow, the therapeutic use of the µAPPJ represents an interesting option for clinical use.

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.

Bioactive Nonthermal Biocompatible Plasma Enhances Migration on Human Gingival Fibroblasts

This study hypothesizes that the application of low-dose nonthermal biocompatible dielectric barrier discharge plasma (DBD-NBP) to human gingival fibroblasts (HGFs) will inhibit colony formation but not cell death and induce matrix metalloproteinase (MMP) expression, extracellular matrix (ECM) degradation, and subsequent cell migration, which can result in enhanced wound healing. HGFs treated with plasma for 3 min migrate to each other across the gap faster than those in the control and 5-min treatment groups on days 1 and 3. The plasma-treated HGFs show significantly high expression levels of the cell cycle arrest-related p21 gene and enhanced MMP activity. Focal adhesion kinase (FAK) mediated attenuation of wound healing or actin cytoskeleton rearrangement, and plasma-mediated reversal of this attenuation support the migratory effect of DBD-NBP. Further, this work performs computer simulations to investigate the effect of oxidation on the stability and conformation of the catalytic kinase domain (KD) of FAK. It is found that the oxidation of highly reactive amino acids (AAs) Cys427, Met442, Cys559, Met571, Met617, and Met643 changes the conformation and increases the structural flexibility of the FAK protein and thus modulates its function and activity. Low-dose DBD-NBP-induces host cell cycle arrest, ECM breakdown, and subsequent migration, thus contributing to the enhanced wound healing process.

Topically Confined Enhancement of Cutaneous Microcirculation by Cold Plasma

INTRODUCTION

We aim to explore potentials and modalities of cold atmospheric pressure plasma (CAP) for the subsequent development of therapies targeting an increased perfusion of the lower leg skin tissue. In this study, we addressed the question whether the microcirculation enhancement is restricted to the tissue in direct contact with plasma or if adjacent tissue might also benefit.

METHODS

A dielectric barrier discharge (DBD)-generated CAP device exhibiting an electrode area of 27.5 cm2 was used to treat the anterior lower leg of ten healthy subjects for 4.5 min. Subsequently, hyperspectral imaging was performed to measure the tempospatially resolved characteristics of microcirculation parameters in superficial (up to 1 mm) and deeper (up to 5 mm) skin layers.

RESULTS

In the tissue area covered by the plasma electrode, DBD-CAP treatment enhances most of the perfusion parameters. The maximum oxygen saturation increase reached 8%, the near-infrared perfusion index (NIR) increased by a maximum of 4%, and the maximum tissue hemoglobin increase equaled 14%. Tissue water index (TWI) was lower in both the control and the plasma groups, thus not affected by the DBD-CAP treatment. Yet, our study reveals that adjacent tissue is hardly affected by the enhancements in the electrode area, and the effects are locally confined.

CONCLUSION

Application of DBD-CAP to the lower leg resulted in enhancement of cutaneous microcirculation that extended 1 h beyond the treatment period with localization to the tissue area in direct contact with the cold plasma. This suggests the possibility of tailoring application schemes for topically confined enhancement of skin microcirculation, e.g., in the treatment of chronic wounds.

Efficacy of Cold Atmospheric Plasma Therapy on Chronic Wounds: An Updated Systematic Review and Meta-Analysis of RCTs

Objective

A previous meta-analysis has revealed that cold atmospheric plasma (CAP) might not be clinically beneficial to chronic wounds. However, several new randomized controlled trials (RCTs) reported that CAP was an effective treatment option for accelerating wound healing in chronic wounds. The purpose of this review is to incorporate these new results and evaluate the efficacy of CAP in chronic wounds.

Methods

The major databases, including PubMed, Embase, Cochrane Library, and Web of Science, were searched for articles related to CAP treatment in chronic wounds until March 21, 2022. The literature retrieval and evaluation were carried out by two independent researchers.

Result

A total of 13 randomized clinical trials published between 2010 and 2022 were finally included. CAP therapy showed to be more effective in reducing the area of wounds (mean difference (MD): -1.74, 95%; confidence interval (CI): [-3.14, -0.33], p = 0.02), compared with non-CAP treatments. The immediate reduction of the bacterial load was higher in the CAP group than in the control group. (MD: -0.37, 95%; CI: [-0.7, -0.05], p = 0.02).

Conclusion

No significant changes were found in long-term antibacterial efficacy and pain perception between the two groups. However, more RCTs of excellent methodological quality are required to confirm technical details of the source of AP and the appropriate duration of the treatment with plasma.

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.

Enhanced growth factor expression in chronic diabetic wounds treated by cold atmospheric plasma

AIMS

Cold atmospheric plasma (CAP) has been proven to enhance wound healing in superficial, chronically infected, diabetic foot ulcers. We aimed to investigate the molecular drivers responsible for this macroscopically observed improvement in diabetic wound healing.

METHODS

Wound exudate was available from each change of dressing within a prospective, randomised, patient-blinded clinical trial. Specific protein level analyses were conducted via multiplex ELISA for wound samples of a representative subcohort (placebo: n = 13; CAP: n = 14). Expression of fibroblast growth factor 2 (FGF-2), vascular endothelial growth factor A (VEGF-A), cytokines and matrix metalloproteinases (MMPs) were evaluated over a treatment period of about 14 days.

RESULTS

Analysis revealed increased levels of the growth factors FGF-2 (placebo: median 46.9 range [32.0-168.6] AU vs. CAP: 113.7[55.8-208.1] AU) and VEGF-A (placebo: 79.7 [52.4-162.7] AU vs. CAP: 120.8 [51.1-198.1] AU) throughout the treatment period and in head-to-head comparison in a daily assessment. CAP-treated wounds showed increased levels of tumour necrosis factor-alpha, interleukins 1α and 8. However, the total protein amounts were not significantly elevated. The total protein amounts of MMPs were not altered by CAP.

CONCLUSIONS

Induction of crucial growth factors, like FGF-2 and VEGF-A, and interleukins appears to be an important component of CAP-mediated promotion of granulation, vascularisation and reepithelialisation in the diabetic foot. These findings demonstrate for the first time that CAP-mediated growth factor induction also occurs in persons with diabetes, as previously described only in several in vitro and rodent experiments. Clinical Trial registration KPWTRIAL: NCT04205942, ClinicalTrials.gov.

A Non-thermal Biocompatible Plasma-Modified Chitosan Scaffold Enhances Osteogenic Differentiation in Bone Marrow Stem Cells

Non-thermal biocompatible plasma (NBP) was considered as an efficient tool in tissue engineering to modify the surface of biomaterials. Three-dimensional chitosan scaffolds have been extensively used in different ways because it holds some remarkable properties, including biodegradability and biocompatibility. In this study, we evaluated the osteogenic potential of NBP-treated chitosan scaffolds using two different plasma sources: a dielectric barrier discharge (NBP-DBD) and a soft jet (NBP-J). The surface modification of the scaffold was evaluated using scanning electron microscopy. For osteogenic differentiation of cells, proliferation and differentiation were tested by using bone marrow-derived stem cells (BMSCs). We observed that cell viability using NBP-DBD and NBP-J treated chitosan scaffolds yielded significant improvements in cell viability and differentiation. The results obtained with MTT and live/dead assays showed that NBP-modified scaffold increases cell metabolic by MTT assay and live/dead assay. It also observed that the NBP treatment is more effective at 5 min with DBD and was selected for further investigations. Enhanced osteogenic differentiation was observed using NBP-treated scaffolds, as reflected by increased alkaline phosphatase activity. Our findings showed that NBP is an innovative and beneficial tool for modifying chitosan scaffolds to increase their activity, making them suitable as biocompatible materials and for bone tissue engineering.

Effect on healing rates of wounds treated with direct cold atmospheric plasma: a case series

OBJECTIVE

The response of different critical acute and hard-to-heal wounds to an innovative wound care modality-direct application of cold atmospheric plasma (CAP)-was investigated in this clinical case series.

METHOD

Over an observation period of two years, acute wounds with at least one risk factor for chronification, as well as hard-to-heal wounds were treated for 180 seconds three times per week with CAP. CAP treatment was additional to standard wound care. Photographs were taken for wound documentation. The wound sizes before the first CAP treatment, after four weeks, after 12 weeks and at wound closure/end of observation time were determined using image processing software, and analysed longitudinally for the development of wound size.

RESULTS

A total of 27 wounds (19 hard-to-heal and eight acute wounds) with a mean wound area of 15cm² and a mean wound age of 49 months were treated with CAP and analysed. All (100%) of the acute wounds and 68% of the hard-to-heal wounds healed after an average treatment duration of 14.2 weeks. At the end of the observation period, 21% of hard-to-heal wounds were not yet closed but were reduced in size by >80%. In 11% of the hard-to-heal wounds (n=2) therapy failed.

CONCLUSION

The results suggested a beneficial effect of additional CAP therapy on wound healing.

DECLARATION OF INTEREST

This work was carried out within the research projects 'Plasma for Life' (funding reference no. 13FH6I04IA) with financial support from the German Federal Ministry of Education and Research (BMBF). In the past seven years AFS has provided consulting services to Evonik and has received institutional support by Heraeus, Johnson & Johnson and Evonik. There are no royalties to disclose. The Department for Trauma Surgery, Orthopaedics and Plastic Surgery received charitable donations by CINOGY GmbH. CINOGY GmbH released the di_CAP devices and electrodes for the study. WV and AH were involved in the development of the used di_CAP device (Plasmaderm, CINOGY GmbH). WV is shareholder of the outsourced start-up company CINOGY GmbH.

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.

The evaluation of efficacy of atmospheric pressure plasma in diabetic ulcers healing: A randomized clinical trial

The aim of this study is to evaluate the efficacy and safety of cold atmospheric plasma (CAP) as a novel therapy for diabetic foot ulcers. This was an investigator-blinded, randomized controlled trial of 14 weeks (6 weeks of treatment and 8 weeks of follow-up). Twenty patients with diabetic foot ulcers were divided into two groups: the control group receiving standard wound care and the plasma group, which received CAP twice a week for six consecutive weeks in addition to standard wound care. The ulcer size, amount of exudate, and wound grading were determined weekly. Cold plasma was produced by applying a high voltage (4.5 kV) and a high frequency (22 kHz) to helium gas. Exudate from wounds treated with CAP showed a significant reduction in the third week after complete treatment (p = 0.039). The wound grading of the ulcers improved by the sixth week (p = 0.019), and the sizes of ulcers significantly decreased in the plasma group at the end of the treatment period (p = 0.007). In this randomized clinical trial, CAP was an effective treatment option for diabetic foot ulcers in terms of wound surface reduction and antibacterial effects.

Liquid-type nonthermal atmospheric plasma enhanced regenerative potential of silk-fibrin composite gel in radiation-induced wound failure

Delayed wound healing in heavily irradiated areas is a serious clinical complication that makes widespread therapeutic use of radiation difficult. Efficient treatment strategies are urgently required for addressing radiation-induced wound failure. Herein, we applied liquid-type nonthermal atmospheric plasma (LTP) to a silk-fibrin (SF) composite gel to investigate whether controlled release of LTP from SF hydrogel not only induced favorable cellular events in an irradiated wound bed but also modulated the SF hydrogel microstructure itself, eventually facilitating the development of a regenerative microenvironment. Scanning electron microscopy and Fourier-transform infrared spectroscopy revealed that LTP modulated the microstructures and chemical bindings of the SF gel. Improved cell viability, morphology, and extracellular matrix depositions by the LTP-treated SF hydrogel were identified with wound-healing assays and immunofluorescence staining. An irradiated random-pattern skin-flap animal model was established in six-week-old C57/BL6 mice. Full-thickness skin was flapped from the dorsum and SF hydrogel was placed underneath the raised skin flap. Postoperative histological analysis of the irradiated random-pattern skin-flap mice model suggested that LTP-treated SF hydrogel much improved wound regeneration and the inflammatory response compared to the SF hydrogel- and sham-treated groups. These results support that LTP-treated SF hydrogel significantly enhanced irradiated wound healing. Cellular and tissue reactions to released LTP from the SF hydrogel were favorable for the regenerative process of the wound; furthermore, mechanochemical properties of the SF gel were improved by LTP.

Non-thermal atmospheric pressure plasma activates Wnt/β-catenin signaling in dermal papilla cells

There is an unmet need for novel, non-pharmacological therapeutics to treat alopecia. Recent studies have shown the potential biological benefits of non-thermal atmospheric pressure plasma (NTAPP), including wound healing, angiogenesis, and the proliferation of stem cells. We hypothesized that NTAPP might have a stimulatory effect on hair growth or regeneration. We designed an NTAPP-generating apparatus which is applicable to in vitro and in vivo experiments. The human dermal papilla (DP) cells, isolated fresh hair follicles, and mouse back skin were exposed with the NTAPP. Biological outcomes were measured using RNA-sequencing, RT-PCR, Western blots, and immunostaining. The NTAPP treatment increased the expression levels of Wnt/β-catenin pathway-related genes (AMER3, CCND1, LEF1, and LRG1) and proteins (β-catenin, p-GSK3β, and cyclin D1) in human DP cells. In contrast, inhibitors of Wnt/β-catenin signaling, endo-IWR1 and IWP2, attenuated the levels of cyclin D1, p-GSK3β, and β-catenin proteins induced by NTAPP. Furthermore, we observed that NTAPP induced the activation of β-catenin in DP cells of hair follicles and the mRNA levels of target genes of the β-catenin signaling pathway (CCND1, LEF1, and TCF4). NTAPP-treated mice exhibited markedly increased anagen induction, hair growth, and the protein levels of β-catenin, p-GSK3β, p-AKT, and cyclin D1. NTAPP stimulates hair growth via activation of the Wnt/β-catenin signaling pathway in DP cells. These findings collectively suggest that NTAPP may be a potentially safe and non-pharmacological therapeutic intervention for alopecia.

The Response and Tolerability of a Novel Cold Atmospheric Plasma Wound Dressing for the Healing of Split Skin Graft Donor Sites: A Controlled Pilot Study

INTRODUCTION

Cold atmospheric plasma (CAP) has positive effects on wound healing and antimicrobial properties. However, an ongoing challenge is the development of specific modes of application for different clinical indications.

OBJECTIVES

We investigated in a prospective pilot study the response and tolerability of a newly developed CAP wound dressing for the acute healing of split skin graft donor sites compared to conventional therapy.

METHODS

We applied both treatments to each patient (n = 10) for 7 days and measured 4 parameters of wound healing every other day (i.e., 1,440 measurements) using a hyperspectral imaging camera. Additionally, we evaluated the clinical appearance and pain levels reported by the patients.

RESULTS

The CAP wound dressing was superior to the control (p < 0.001) in the improvement of 3 wound parameters, that is, deep tissue oxygen saturation, hemoglobin distribution, and tissue water distribution. CAP was well tolerated, and pain levels were lower in CAP-treated wound areas.

CONCLUSION

CAP wound dressing is a promising new tool for acute wound healing.

The Quest to Quantify Selective and Synergistic Effects of Plasma for Cancer Treatment: Insights from Mathematical Modeling

Cold atmospheric plasma (CAP) and plasma-treated liquids (PTLs) have recently become a promising option for cancer treatment, but the underlying mechanisms of the anti-cancer effect are still to a large extent unknown. Although hydrogen peroxide (H2O2) has been recognized as the major anti-cancer agent of PTL and may enable selectivity in a certain concentration regime, the co-existence of nitrite can create a synergistic effect. We develop a mathematical model to describe the key species and features of the cellular response toward PTL. From the numerical solutions, we define a number of dependent variables, which represent feasible measures to quantify cell susceptibility in terms of the H2O2 membrane diffusion rate constant and the intracellular catalase concentration. For each of these dependent variables, we investigate the regimes of selective versus non-selective, and of synergistic versus non-synergistic effect to evaluate their potential role as a measure of cell susceptibility. Our results suggest that the maximal intracellular H2O2 concentration, which in the selective regime is almost four times greater for the most susceptible cells compared to the most resistant cells, could be used to quantify the cell susceptibility toward exogenous H2O2. We believe our theoretical approach brings novelty to the field of plasma oncology, and more broadly, to the field of redox biology, by proposing new ways to quantify the selective and synergistic anti-cancer effect of PTL in terms of inherent cell features.

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.

[Effect of sliding discharge on proliferation and death of brain microvessel endothelial cells in vitro]

The dose-dependent effects of plasma exposure to a unipolar nanosecond sliding discharge over the surface of the culture medium in a closed plate on the cells of cerebral endothelium in vitro were studied. Using a 24-well plate, the surface plasma energy density of one pulse was 360 μJ/cm2 at a pulse frequency of 100 Hz. It has been shown that in the creeping discharge plasma there is an active excitation of air molecules, the formation of positive nitrogen and oxygen ions, and the formation of carbon monoxide. In the dose density range of 0-32 J/cm2, the dose-dependent effects were assessed in the 4-12 h post-radiation period. Cell death was analyzed with an assessment of the total number of cells, necrotic cells, cells in apoptosis (phosphatidylserine externalization, internucleosomal DNA fragmentation) and their proliferative activity (Ki67-immunopositive cells). A preliminary assessment of subtle dose-dependent effects indicates the peculiarities of the effect of small doses.

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.

On the Anti-Cancer Effect of Cold Atmospheric Plasma and the Possible Role of Catalase-Dependent Apoptotic Pathways

Cold atmospheric plasma (CAP) is a promising new agent for (selective) cancer treatment, but the underlying cause of the anti-cancer effect of CAP is not well understood yet. Among different theories and observations, one theory in particular has been postulated in great detail and consists of a very complex network of reactions that are claimed to account for the anti-cancer effect of CAP. Here, the key concept is a reactivation of two specific apoptotic cell signaling pathways through catalase inactivation caused by CAP. Thus, it is postulated that the anti-cancer effect of CAP is due to its ability to inactivate catalase, either directly or indirectly. A theoretical investigation of the proposed theory, especially the role of catalase inactivation, can contribute to the understanding of the underlying cause of the anti-cancer effect of CAP. In the present study, we develop a mathematical model to analyze the proposed catalase-dependent anti-cancer effect of CAP. Our results show that a catalase-dependent reactivation of the two apoptotic pathways of interest is unlikely to contribute to the observed anti-cancer effect of CAP. Thus, we believe that other theories of the underlying cause should be considered and evaluated to gain knowledge about the principles of CAP-induced cancer cell death.

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.

Rapid Airborne Influenza Virus Quantification Using an Antibody-Based Electrochemical Paper Sensor and Electrostatic Particle Concentrator

Airborne influenza viruses are responsible for serious respiratory diseases, and most detection methods for airborne viruses are based on extraction of nucleic acids. Herein, vertical-flow-assay-based electrochemical paper immunosensors were fabricated to rapidly quantify the influenza H1N1 viruses in air after sampling with a portable electrostatic particle concentrator (EPC). The effects of antibodies, anti-influenza nucleoprotein antibodies (NP-Abs) and anti-influenza hemagglutinin antibodies (HA-Abs), on the paper sensors as well as nonpulsed high electrostatic fields with and without corona charging on the virus measurement were investigated. The antigenicity losses of the surface (HA) proteins were caused by H₂O₂ via lipid oxidation-derived radicals and ¹O₂ via direct protein peroxidation upon exposure of a high electrostatic field. However, minimal losses in antigenicity of NP of the influenza viruses were observed, and the concentration of the H1N1 viruses was more than 160 times higher in the EPC than the BioSampler upon using NP-Ab based paper sensors after 60 min collection. This NP-Ab-based paper sensors with the EPC provided measurements comparable to quantitative polymerase chain reaction (qPCR) but much quicker, specific to the influenza H1N1 viruses in the presence of other airborne microorganisms and beads, and more cost-effective than enzyme-linked immunosorbent assay and qPCR.

Critical Analysis of Non-Thermal Plasma-Driven Modulation of Immune Cells from Clinical Perspective

The emerged field of non-thermal plasma (NTP) shows great potential in the alteration of cell redox status, which can be utilized as a promising therapeutic implication. In recent years, the NTP field considerably progresses in the modulation of immune cell function leading to promising in vivo results. In fact, understanding the underlying cellular mechanisms triggered by NTP remains incomplete. In order to boost the field closer to real-life clinical applications, there is a need for a critical overview of the current state-of-the-art. In this review, we conduct a critical analysis of the NTP-triggered modulation of immune cells. Importantly, we analyze pitfalls in the field and identify persisting challenges. We show that the identification of misconceptions opens a door to the development of a research strategy to overcome these limitations. Finally, we propose the idea that solving problems highlighted in this review will accelerate the clinical translation of NTP-based treatments.

Quantitation of the ROS production in plasma and radiation treatments of biotargets

Medical treatment utilizing non-thermal plasma is based on the production of reactive oxygen species (ROS) and their interactions with biomatters. On the basis of empirical data from practices, plasma treatment has been planned with regard to the setup of a plasma generator's parameters, including gas combination, gas-flow rate, and applied voltage. In this study, we quantitated plasma treatment in terms of the plasma dose on the target matter, which can be contrasted with the radiation dose to targets under radiation exposure. We measured the OH radical production in cell culture medium and intracellular ROS production from plasma treatment in comparison with those from X-ray exposure. The clonogenic cell deaths from plasma and X-ray exposures were also compared. In plasma treatment, the clonogenic cell death was better predicted by intracellular ROS production rather than by medium OH production.

The Effect of Atmospheric Cold Plasma on Bacterial Stress Responses and Virulence Using Listeria monocytogenes Knockout Mutants

Listeria monocytogenes is an opportunistic intracellular pathogen commonly associated with serious infections and multiple food-borne outbreaks. In this study, we investigated the influence of atmospheric cold plasma (80 kV, 50 Hz) on L. monocytogenes (EGD-e) and its knockout mutants of sigB, rsbR, prfA, gadD, and lmo0799 genes at different treatment time intervals. Further, to ascertain if sub-lethal environmental stress conditions could influence L. monocytogenes survival and growth responses, atmospheric cold plasma (ACP) resistance was evaluated for the cultures exposed to cold (4°C) or acid (pH 4) stress for 1 h. The results demonstrate that both wild-type and knockout mutants were similarly affected after 1 min exposure to ACP (p > 0.05), with a difference in response noted only after 3 min of treatment. While all L. monocytogenes strains exposed to acid/cold stress were hypersensitive to ACP treatment and were significantly reduced or inactivated within 1 min of treatment (p < 0.05). The results indicate sigB and prfA are important for general stress resistance and biofilm, respectively, loss of these two genes significantly reduced bacterial resistance to ACP treatment. In addition, exposure to sub-lethal 1min ACP increased the gene expression of stress associated genes. SigB showed the highest gene expression, increasing by 15.60 fold, followed by gadD2 (7.19) and lmo0799 (8.6) after 1 min exposure. Overall, an increase in gene expression was seen in all stress associated genes analyzed both at 1 min treatment; while long treatment time reduced the gene expression and some cases down-regulated prfA and gadD3 gene expression. By comparing the response of mutants under ACP exposure to key processing parameters, the experimental results presented here provide a baseline for understanding the bacterial genetic response and resistance to cold plasma stress and offers promising insights for optimizing ACP applications.

Modifying the Tumour Microenvironment: Challenges and Future Perspectives for Anticancer Plasma Treatments

Tumours are complex systems formed by cellular (malignant, immune, and endothelial cells, fibroblasts) and acellular components (extracellular matrix (ECM) constituents and secreted factors). A close interplay between these factors, collectively called the tumour microenvironment, is required to respond appropriately to external cues and to determine the treatment outcome. Cold plasma (here referred as ‘plasma’) is an emerging anticancer technology that generates a unique cocktail of reactive oxygen and nitrogen species to eliminate cancerous cells via multiple mechanisms of action. While plasma is currently regarded as a local therapy, it can also modulate the mechanisms of cell-to-cell and cell-to-ECM communication, which could facilitate the propagation of its effect in tissue and distant sites. However, it is still largely unknown how the physical interactions occurring between cells and/or the ECM in the tumour microenvironment affect the plasma therapy outcome. In this review, we discuss the effect of plasma on cell-to-cell and cell-to-ECM communication in the context of the tumour microenvironment and suggest new avenues of research to advance our knowledge in the field. Furthermore, we revise the relevant state-of-the-art in three-dimensional in vitro models that could be used to analyse cell-to-cell and cell-to-ECM communication and further strengthen our understanding of the effect of plasma in solid tumours.

Study on Chemical Modifications of Glutathione by Cold Atmospheric Pressure Plasma (Cap) Operated in Air in the Presence of Fe(II) and Fe(III) Complexes

Cold atmospheric pressure plasma is an attractive new research area in clinical trials to treat skin diseases. However, the principles of plasma modification of biomolecules in aqueous solutions remain elusive. It is intriguing how reactive oxygen and nitrogen species (RONS) produced by plasma interact on a molecular level in a biological environment. Previously, we identified the chemical effects of dielectric barrier discharges (DBD) on the glutathione (GSH) and glutathione disulphide (GSSG) molecules as the most important redox pair in organisms responsible for detoxification of intracellular reactive species. However, in the human body there are also present redox-active metals such as iron, which is the most abundant transition metal in healthy humans. In the present study, the time-dependent chemical modifications on GSH and GSSG in the presence of iron(II) and iron(III) complexes caused by a dielectric barrier discharge (DBD) under ambient conditions were investigated by IR spectroscopy, mass spectrometry and High Performance Liquid Chromatography (HPLC). HPLC chromatograms revealed one clean peak after treatment of both GSH and GSSH with the dielectric barrier discharge (DBD) plasma, which corresponded to glutathione sulfonic acid GSO₃H. The ESI-MS measurements confirmed the presence of glutathione sulfonic acid. In our experiments, involving either iron(II) or iron(III) complexes, glutathione sulfonic acid GSO₃H appeared as the main oxidation product. This is in sharp contrast to GSH/GSSG treatment with DBD plasma in the absence of metal ions, which gave a wild mixture of products. Also interesting, no nitrosylation of GSH/GSSG was oberved in the presence of iron complexes, which seems to indicate a preferential oxygen activation chemistry by this transition metal ion.

Elevated H2AX Phosphorylation Observed with kINPen Plasma Treatment Is Not Caused by ROS-Mediated DNA Damage but Is the Consequence of Apoptosis

Phosphorylated histone 2AX (γH2AX) is a long-standing marker for DNA double-strand breaks (DSBs) from ionizing radiation in the field of radiobiology. This led to the perception of γH2AX being a general marker of direct DNA damage with the treatment of other agents such as low-dose exogenous ROS that unlikely act on cellular DNA directly. Cold physical plasma confers biomedical effects majorly via release of reactive oxygen and nitrogen species (ROS). In vitro, increase of γH2AX has often been observed with plasma treatment, leading to the conclusion that DNA damage is a direct consequence of plasma exposure. However, increase in γH2AX also occurs during apoptosis, which is often observed with plasma treatment as well. Moreover, it must be questioned if plasma-derived ROS can reach into the nucleus and still be reactive enough to damage DNA directly. We investigated γH2AX induction in a lymphocyte cell line upon ROS exposure (plasma, hydrogen peroxide, or hypochlorous acid) or UV-B light. Cytotoxicity and γH2AX induction was abrogated by the use of antioxidants with all types of ROS treatment but not UV radiation. H2AX phosphorylation levels were overall independent of analyzing either all nucleated cells or segmenting γH2AX phosphorylation for each cell cycle phase. SB202190 (p38-MAPK inhibitor) and Z-VAD-FMK (pan-caspase inhibitor) significantly inhibited γH2AX induction upon ROS but not UV treatment. Finally, and despite γH2AX induction, UV but not plasma treatment led to significantly increased micronucleus formation, which is a functional read-out of genotoxic DNA DSBs. We conclude that plasma-mediated and low-ROS γH2AX induction depends on caspase activation and hence is not the cause but consequence of apoptosis induction. Moreover, we could not identify lasting mutagenic effects with plasma treatment despite phosphorylation of H2AX.

Non-Thermal Plasma Accelerates Astrocyte Regrowth and Neurite Regeneration Following Physical Trauma In Vitro

Non-thermal plasma (NTP), defined as a partially ionized gas, is an emerging technology with several biomedical applications, including tissue regeneration. In particular, NTP treatment has been shown to activate endogenous biological processes to promote cell regrowth, differentiation, and proliferation in multiple cell types. However, the effects of this therapy on nervous system regeneration have not yet been established. Accordingly, the current study explored the effects of a nanosecond-pulsed dielectric barrier discharge plasma on neural regeneration. Following mechanical trauma in vitro, plasma was applied either directly to (1) astrocytes alone, (2) neurons alone, or (3) neurons or astrocytes in a non-contact co-culture. Remarkably, we identified NTP treatment intensities that accelerated both neurite regeneration and astrocyte regrowth. In astrocyte cultures alone, an exposure of 20–90 mJ accelerated astrocyte re-growth up to three days post-injury, while neurons required lower treatment intensities (≤20 mJ) to achieve sub-lethal outgrowth. Following injury to neurons in non-contact co-culture with astrocytes, 20 mJ exposure of plasma to only neurons or astrocytes resulted in increased neurite regeneration at three days post-treatment compared to the untreated, but no enhancement was observed when both cell types were treated. At day seven, although regeneration further increased, NTP did not elicit a significant increase from the control. However, plasma exposure at higher intensities was found to be injurious, underscoring the need to optimize exposure levels. These results suggest that growth-promoting physiological responses may be elicited via properly calibrated NTP treatment to neurons and/or astrocytes. This could be exploited to accelerate neurite re-growth and modulate neuron-astrocyte interactions, thereby hastening nervous system regeneration.

Wound Healing Potential of Low Temperature Plasma in Human Primary Epidermal Keratinocytes

BACKGROUND

Low temperature plasma (LTP) was recently shown to be potentially useful for biomedical applications such as bleeding cessation, cancer treatment, and wound healing, among others. Keratinocytes are a major cell type that migrates directionally into the wound bed, and their proliferation leads to complete wound closure during the cutaneous repair/regeneration process. However, the beneficial effects of LTP on human keratinocytes have not been well studied. Therefore, we investigated migration, growth factor production, and cytokine secretion in primary human keratinocytes after LTP treatment.

METHODS

Primary cultured keratinocytes were obtained from human skin biopsies. Cell viability was measured with the EZ-Cytox cell viability assay, cell migration was evaluated by an in vitro wound healing assay, gene expression was analyzed by quantitative real-time polymerase chain reaction, and protein expression was measured by enzyme-linked immunosorbent assays and western blotting after LTP treatment.

RESULTS

Cell migration, the secretion of several cytokines, and gene and protein levels of angiogenic growth factors increased in LTP-treated human keratinocytes without associated cell toxicity. LTP treatment also significantly induced the expression of hypoxia inducible factor-1α (HIF-1α), an upstream regulator of angiogenesis. Further, the inhibition of HIF-1α expression blocked the production of angiogenic growth factors induced by LTP in human keratinocytes.

CONCLUSION

Our results suggest that LTP treatment is an effective approach to modulate wound healing-related molecules in epidermal keratinocytes and might promote angiogenesis, leading to improved wound healing.

Pyruvate Plays a Main Role in the Antitumoral Selectivity of Cold Atmospheric Plasma in Osteosarcoma

Osteosarcoma (OS) is the most common primary bone tumor but current therapies still have poor prognosis. Cold Atmospheric Plasma (CAP) and Plasma activated media (PAM) have shown potential to eliminate cancer cells in other tumors. It is thought that Reactive Oxygen and Nitrogen species (RONS) in PAM are key players but cell culture media composition alters treatment outcomes and data interpretation due to scavenging of certain RONS. In this work, an atmospheric pressure plasma jet was employed to obtain PAM in the presence or absence of pyruvate and used to treat the SaOS-2 (OS) cell line or hBM-MSC healthy cells. OS cells show higher sensitivity to PAM treatment than healthy cells, both in medium with and without pyruvate, activating apoptosis, DNA damage and deregulating cellular pathways mediated by c-JUN, AKT, AMPK or STAT3. In line with previous works, lack of pyruvate increases cytotoxic potential of PAM affecting cancer and healthy cells by increasing 10–100 times the concentration of H₂O₂ without altering that of nitrites and thus decreasing CAP anti-tumor selectivity. Suitable conditions for CAP anti-cancer selectivity can be obtained by modifying plasma process parameters (distance, flow, treatment time) to obtain adequate balance of the different RONS in cell culture media.

Potential Applications of Non-thermal Plasma in Animal Husbandry to Improve Infrastructure

Infrastructure in animal husbandry refers to fundamental facilities and services necessary for better living conditions of animals and its economy to function through better productivity. Mainly, infrastructure can be divided into two categories: hard infrastructure and soft infrastructure. Physical infrastructure, such as buildings, roads, and water supplying systems, belongs to hard infrastructure. Soft infrastructure includes services which are required to maintain economic, health, cultural and social standards of animal husbandry. Therefore, the proper management of infrastructure in animal husbandry is necessary for animal welfare and its economy. Among various technologies to improve the quality of infrastructure, non-thermal plasma (NTP) technology is an effectively applicable technology in different stages of animal husbandry. NTP is mainly helpful in maintaining better health conditions of animals in several ways via decontamination from microorganisms present in air, water, food, instruments and surfaces of animal farming systems. Furthermore, NTP is used in the treatment of waste water, vaccine production, wound healing in animals, odor-free ventilation, and packaging of animal food or animal products. This review summarizes the recent studies of NTP which can be related to the infrastructure in animal husbandry.

Promotion of osteogenic differentiation by non-thermal biocompatible plasma treated chitosan scaffold

Non-thermal biocompatible plasma (NBP) has recently emerged as an attractive tool for surface modification of biomaterials in tissue engineering. Three dimensional chitosan scaffolds have been widely used in bone tissue engineering due to biodegradable and biocompatible properties. The present study aimed to evaluate osteogenic potential of NBP treated chitosan scaffold. The surface characteristics of scaffolds were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), cell proliferation and differentiation was tested with osteoprogenitor cell line MC3T3-E1. The results show that NBP modified scaffold increase cell metabolic by MTT assay and live/dead assay. More importantly, we evidenced enhancement of osteogenic differentiation on NBP treated scaffolds by an increase of alkaline phosphatase (ALP) activity, high degree of extracellular mineralization and up-regulated osteogenic marker genes expression level. The findings in our study highlighted NBP as the innovative method to modified chitosan scaffold and to fine-tuning the scaffold a more suitable and beneficial biomaterial for in vivo bone tissue engineering and clinical bone defects therapies.

Treatment of Infected Wounds in the Age of Antimicrobial Resistance: Contemporary Alternative Therapeutic Options

As antibiotic resistance increases and antimicrobial options diminish, there is a pressing need to identify and develop new and/or alternative (non-antimicrobial-based) wound therapies. The authors describe the implications of antibiotic resistance on their current wound treatment paradigms and review the most promising non-antibiotic-based antimicrobial agents currently in research and development, with a focus on preclinical and human studies of therapeutic bacteriophages, antimicrobial peptides, cold plasma treatment, photodynamic therapy, honey, silver, and bioelectric dressings.

Plasma and Nanomaterials: Fabrication and Biomedical Applications

Application of plasma medicine has been actively explored during last several years. Treating every type of cancer remains a difficult task for medical personnel due to the wide variety of cancer cell selectivity. Research in advanced plasma physics has led to the development of different types of non-thermal plasma devices, such as plasma jets, and dielectric barrier discharges. Non-thermal plasma generates many charged particles and reactive species when brought into contact with biological samples. The main constituents include reactive nitrogen species, reactive oxygen species, and plasma ultra-violets. These species can be applied to synthesize biologically important nanomaterials or can be used with nanomaterials for various kinds of biomedical applications to improve human health. This review reports recent updates on plasma-based synthesis of biologically important nanomaterials and synergy of plasma with nanomaterials for various kind of biological applications.

Improved Wound Healing of Airway Epithelial Cells Is Mediated by Cold Atmospheric Plasma: A Time Course-Related Proteome Analysis

The promising potential of cold atmospheric plasma (CAP) treatment as a new therapeutic option in the field of medicine, particularly in Otorhinolaryngology and Respiratory medicine, demands primarily the assessment of potential risks and the prevention of any direct and future cell damages. Consequently, the application of a special intensity of CAP that is well tolerated by cells and tissues is of particular interest. Although improvement of wound healing by CAP treatment has been described, the underlying mechanisms and the molecular influences on human tissues are so far only partially characterized. In this study, human S9 bronchial epithelial cells were treated with cold plasma of atmospheric pressure plasma jet that was previously proven to accelerate the wound healing in a clinically relevant extent. We studied the detailed cellular adaptation reactions for a specified plasma intensity by time-resolved comparative proteome analyses of plasma treated vs. nontreated cells to elucidate the mechanisms of the observed improved wound healing and to define potential biomarkers and networks for the evaluation of plasma effects on human epithelial cells. K-means cluster analysis and time-related analysis of fold-change factors indicated concordantly clear differences between the short-term (up to 1 h) and long-term (24-72 h) adaptation reactions. Thus, the induction of Nrf2-mediated oxidative and endoplasmic reticulum stress response, PPAR-alpha/RXR activation as well as production of peroxisomes, and prevention of apoptosis already during the first hour after CAP treatment are important cell strategies to overcome oxidative stress and to protect and maintain cell integrity and especially microtubule dynamics. After resolving of stress, when stress adaptation was accomplished, the cells seem to start again with proliferation and cellular assembly and organization. The observed strategies and identification of marker proteins might explain the accelerated wound healing induced by CAP, and these indicators might be subsequently used for risk assessment and quality management of application of nonthermal plasma sources in clinical settings.

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).

Medical applications of nonthermal atmospheric pressure plasma in dermatology

Plasma is an ionized gas that consists of positively and negatively charged particles, neutral atoms, and photons. Recent developments in plasma sources have made it possible to generate room-temperature plasma in the "open air", thus enabling the application of plasma in vivo. Using nonthermal plasma, active agents can be efficiently delivered to target cells without creating thermal damage. Also known as cold atmospheric pressure plasma (CAP), nonthermal atmospheric pressure plasma offers innovative medical applications. In this context, it has also gained wide attention in the field of dermatology. The complex and variable mixture of active agents in plasma - predominantly reactive oxygen and nitrogen species (ROS, RNS) - can control or trigger complex biochemical reactions, achieving the desired effects in a dose-dependent manner. The objective of the present review is to present potential applications of plasma in dermatology and analyze its potential mechanisms of action.