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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. [ABSTRACT FROM AUTHOR]

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

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

The aim of this experiment is to enhance selected species in atmospheric pressure plasma jet (APPJ) that might be helpful for the wound healing purpose and to test the performance using basic diagnosis in plasma-treated liquid. A homemade APPJ device is driven by sinusoidal voltage with a excitation frequency of 25 kHz. Argon with admixture of small percentage of nitrogen, oxygen, and water vapor was selected to be carrier gas as the main sources of reactive species. Discharge power consumption is calculated by two approaches. Reactive oxygen species and reactive nitrogen species in the excited states are characterized by optical emission spectroscopy (OES). Excitation temperature $T_{\mathrm {exc}}$ in argon plasmas is calculated to estimate the electron energy distribution. The results show that argon plasmas with small addition of nitrogen and oxygen in this jet configuration are more efficient to generate desired reactive species in terms of OES diagnosis and liquid acidification. Moreover, the distinct efficiency of liquid acidification between direct and indirect plasma treatment of liquid has also been observed. [ABSTRACT FROM AUTHOR]

Plasma medicine is a rapidly advancing field. As one promising application, cold plasma has been ascribed a beneficial role in wound healing in which monocytes/macrophages play an important part. Wound healing and many other physiological and pathological processes are subject to redox control. Cold plasma expels reactive species of many kinds, thereby altering the redox state and mediating cell and tissue responses. Controlling this species efflux could be a valuable asset to control biological effects. We, therefore, investigated the biological response of a plasma treatment regimen that was gas shielded from the ambient environment. In this gas curtain, several N2:O2 ratios were investigated, and we discovered a modulation within the composition of active compounds (NO-2 , NO-3 , and H2O2) in physiological solutions. Using a human monocyte cell line, the cell's scavenging activity toward these molecules was assessed. With regard to cellular processes important in wound healing, such as cytokines release, O2 shielding provided stronger stimulation compared to N2 shielding. Altogether, the results support the idea that tuning the plasma-derived reactive species composition may be an interesting approach to improve plasma medical applications. [ABSTRACT FROM AUTHOR]

Objective The microcirculatory response of intact human skin to exposure with di CAP for different durations with a focus on the effect of implied mechanical pressure during plasma treatment was investigated. Methods Local relative hemoglobin, blood flow velocity, tissue oxygen saturation, and blood flow were monitored noninvasively for up to 1 hour in 1-2 mm depth by optical techniques, as well as temperature, pH values, and moisture before and after skin stimulation. The experimental protocol (N = 10) was set up to differentiate between pressure- and plasma-induced effects. Results Significant increases in microcirculation were only observed after plasma stimulation but not after pressure stimulus alone. For a period of 1 h after stimulation, local relative hemoglobin was increased by 5.1% after 270 seconds diCAP treatment. Tissue oxygen saturation increased by up to 9.4%, whereas blood flow was doubled (+106%). Skin pH decreased by 0.3 after 180 seconds and 270 seconds diCAP treatment, whereas skin temperature and moisture were not affected. Conclusions diCAP treatment of intact skin notably enhances microcirculation for a therapeutically relevant period. This effect is specific to the plasma treatment and not an effect of the applied pressure. Prolonged treatment durations lead to more pronounced effects. [ABSTRACT FROM AUTHOR]

We evaluated a nonthermal plasma jet for a respective use to prevent infections from bacteria and yeasts. The plasma jet is generated from the flow of ambient air with 8 slm through a microhollow cathode discharge assembly that is operated with a direct current of 30 mA. With these parameters, the temperature in the jet reaches 43 ^\circ\C at 10 mm from the discharge. Agar plates that were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Candida kefyr were treated at this distance, moving the plates through the jet in a meander that covered a 2 cm by 2 cm area. Different exposure times were realized by changing the speed of the movement and adjusting the distance between consecutive passes. S. aureus was most responsive to the exposure with a reduction in the number of colony forming units of 5.5 log steps in 40 s. All other microorganisms show a more gradual inactivation with exposure times. For all bacteria, a clearing of the treated area is achieved in about 2.5–3.5 min, corresponding to log-reduction factors of 5.5–6.5. Complete inactivation of the yeast requires about 7 min. Both S. aureus and C. kefyr show considerable inactivation also outside the immediate treatment area, while P. aeruginosa and A. baumannii do not. We conclude that differences in the morphologies of the membrane structures are responsible for the diverging results, together with a targeted response to different agents provided with the plasma jet. For the gram negative bacteria, we hold short-lived agents, acting across a short range, responsible, while for the other microorganisms, longer lived species seem more important. Our measurements show that neither heat, ultraviolet radiation, nor the generation of ozone can be responsible for the observed results. The most prominent long lived reaction product found is nitric oxide, which, by itself or through induced chemical reactions, might affect cell viability. [ABSTRACT FROM PUBLISHER]

Plasma medicine is emerging worldwide, and some promising applications seem to be near the horizon. Direct therapeutic plasma application as the central field of plasma medicine will bring physical plasmas directly on or in a human (or animal) body. Campus PlasmaMed is a research association supported by the German Federal Ministry of Education and Research (BMBF), concentrated in the northeast of Germany and founded to explore promising and safe applications of atmospheric-pressure plasmas in medical therapy based on systematic and interdisciplinary basic research on the interactions of plasma components with living systems. Whereas a broad spectrum of plasma sources dedicated for biomedical applications has been reported during recent years, mainly two basic principles of plasma sources are used in the Campus PlasmaMed: atmospheric-pressure plasma jets and dielectric barrier discharges. A comprehensive assessment of potential risk factors, such as gas temperature, power transfer from plasma to the target, (V)UV radiation emission, or the generation of toxic gases and its release into the adjacencies, which could be dangerous for patients and therapists, has to be done as a basic precondition before any biomedical experiments can be started or a potential therapeutic application can be taken into consideration. Despite the fact that the initial plasma-source characterization and optimization are in the main responsibility of plasma physicists and engineers, potential users from the biomedical field should be integrated as soon as possible to include special needs and constraints for specific applications during early steps of development. This multidisciplinary research cooperation among plasma scientists and engineers on the one side and life scientists and clinicians on the other is one of the main characteristics of the Campus PlasmaMed. Such interdisciplinary cooperation is more than ever required for the characterization of biological effects of plasma sources, which has to be realized by a multistep program, starting with the investigations of plasma–liquid interactions and including a broad spectrum of in vitro tests with cells, as well as cell and tissue cultures up to isolated tissues or organs to be proved finally with animal experiments and clinical trials. Because there are no standardized criteria so far according to which atmospheric-pressure plasma sources can be assessed as to their suitability for medical applications, interdisciplinary results from plasma medical research have to be transferred into rules and standards to guarantee successful and safe practical application, including economic exploitation of plasma-medical research results. [ABSTRACT FROM AUTHOR]

It is now well known that low-temperature plasmas can inactivate bacteria effectively. At low doses, these plasmas can also help in the proliferation of healthy fibroblasts and detach damaged cells without causing necrosis. The combination of these characteristics leads to the possibility of using plasmas in biomedical applications such as wound healing. Although only limited understanding is available as to the mechanisms whereby plasmas interact with cells (prokaryotic or eukaryotic), it is now well established that the effects of plasmas on biological cells depend on the cell type, the cell concentration, and the medium supporting them. In this paper, we present clear visual evidence of these dependencies in the case of bacteria. Through simple imaging, we show that the size and shape of the inactivation zone depend on the type of bacteria, their initial concentrations, and the medium supporting the cells. [ABSTRACT FROM AUTHOR]

The intersection of plasma filaments in a dielectric barrier discharge with a small wound in the human skin in the context of plasma medicine is investigated with results from a computer model. The relative location of the filament with respect to the wound determines the symmetry of treatment. [ABSTRACT FROM AUTHOR]