Cold Atmospheric Argon Plasma Research Articles

(268) Prevention of Driveline Infections with Cold Atmospheric Argon Plasma: A Randomized Trial Comparing Two Surgical Techniques

(268) Prevention of Driveline Infections with Cold Atmospheric Argon Plasma: A Randomized Trial Comparing Two Surgical Techniques

Canal pretreatment using cold atmospheric argon plasma, chitosan and Chlorine p6 activated by photodynamic therapy with EDTA as a final irrigant on the pushout bond strength of fiber post

AimsTo evaluate the effect of contemporary root canal irrigants i.e., Cold atmospheric argon plasma (CAAP), Chlorine p6 (Clp6), and chitosan on the push-out bond strength (PBS) of glass fiber post (GFP) and marten hardness (MH) of root canal dentin compared to NaOCl+EDTA. Materials and methodsThe anatomic crown of sixty human mandibular premolars was removed by transversal section till cement-enamel junction (CEJ). Root canals were prepared and canals were dried and obturated using gutta-percha points and AH plus sealer. Post space was prepared and specimens were arbitrarily divided into four groups based on the post-space irrigation. (n = 15) Group 1: 5.25% NaOCl + 17% EDTA, Group 2: CAAP + 17% EDTA, Group 3: Chitosan + 17% EDTA and Group 4: Clp6 + 17% EDTA. For MH evaluation five samples from each disinfected group were taken and MH was assessed with the help of an ultra microhardness tester. GFP was cemented using self-etch dual cure cement on the remaining 10 samples from each group. Samples were vertically planted in acrylic resin blocks 1 mm thick slices were subjected to push-out testing and failure mode analysis using a universal testing machine and Stereomicroscope. ANOVA and Tukey multiple comparison tests were used to compare the means of bond integrity attained (p = 0.05). ResultsThe maximum values of PBS and MH were displayed in group 1 (5.25% NaOCl + 17% EDTA) specimens. However, group 3 exhibited the minimum values of bond strength and MH scores. Intergroup comparison analysis revealed that group 2, group 3, and group 4 displayed comparable outcomes of PBS and MH (p > 0.05). The cervical and middle third of group 1 specimens displayed a cohesive type of failure. However, the apical section of group 1 and other tested groups exhibited the adhesive type of failure. ConclusionCanal irrigation with 5.25% NaOCl and 17% EDTA appears to be better in terms of improving the bond integrity of fiber posts with no compromise in MH of the dentin as compared to the contemporary irrigant used.

Cold atmospheric plasma: Its time-dependent effects on the elimination of bacterial colony on periodontal manual scalers.

This in vitro study investigated the time-dependent bactericidal effects of cold atmospheric argon plasma treatment of periodontal hand scalers as well as the scanning electron microscopic view of the scaler tip surfaces before and after plasma treatment. The study used 34 periodontal hand scalers which were divided into test and control groups. The scaler tips were inoculated with Escherichia coli and Staphylococcus aureus bacteria, following which the scalers in the control and test groups were subjected to conventional sterilization and argon plasma sterilization, respectively. Varying exposure times of plasma treatment were done on the test group samples to evaluate the minimum time required for complete sterilization. Subsequently, streaks were made on plate count agar using each of these instruments. The agar plates were then kept in an incubator for 24 h, following which bacterial colony count was assessed (colony-forming units/mL). Furthermore, the scanning electron microscopic (SEM) view of the scaler tip was studied before and after plasma treatment. A complete elimination of bacterial load (Gram-positive as well as Gram-negative) from the instrument surface was achieved by the plasma exposure time of 15-20 s. SEM analysis did not show a significant difference before and after plasma treatment as not many organic residues were present on the scaler tip. Cold atmospheric pressure plasma is an efficient and time-saving method of sterilization, capable of destroying both Gram-positive and Gram-negative bacteria.

Risk assessment of a cold atmospheric physical argon plasma jet on the skin, liver, and biochemical factors in an animal model.

In this study, an argon plasma jet was made for therapeutic purposes. Although cold plasma jet (CAPJ) is considered a safe device, its risk assessment is essential to be approved for a clinical trial. To this end, the safety parameters of the CAPJ were evaluated from both aspects associated with the instrument such as design, construction, and environmental conditions, and also function on living organisms. It was shown that the device is physically safe for the user and the animal. In continue, healthy rats were treated by the plasma at two modes of streamer and plume mode at two distances of 20 and 25 mm from the nozzle for 2, 5, and 10 minutes of exposure time. In the study of blood serum biochemistry, the strongest deviation from the average is observed at alkaline phosphatase in the plume mode in the 10min (P10) group. Also, the amount of Aspartate transaminase (AST) in the blood serum of rats is lower than the control group for all groups except streamer mode at 10 min exposure (S10). And, the mean ALT enzyme in the serum of the S5 group is significantly higher compared to the plume mode in the 5 min (P5) group. The histopathology of the liver is studied to support these results. Shrinkage of the nucleus, cell swelling, and hyperemia are observed in the liver tissue for streamer mode, while in the plasma plume mode, these changes are not tangible. No significant difference is observed in the mean value of total Bilirubin, Direct Bilirubin, Albumin, Na, and K factors in the different groups after the plasma treatment and the histopathology of kidney tissue is performed for all the groups to support this conclusion and it did not show any damage to the kidney tissue. As a result of risk assessment in this study, the treatment with a duration of 2 to 5 minutes is safe with the specifically designed CAPJ nozzle head at a distance of 25 mm from the nozzle.

Effect of Root Dentin Pretreatment on Micro-Push-Out Bond Strength of Fiber Posts to Root Canal Dentin: Cold Atmospheric Argon Plasma (CAAP) and Ethylenediaminetetraacetic Acid (EDTA).

Purpose Debonding from the root canal dentin is the most common failure mode of fiber posts. This study aimed to assess the effects of cold atmospheric argon plasma (CAAP) and ethylenediaminetetraacetic acid (EDTA) on micro-push-out bond strength of fiber posts to root canal dentin. Materials and Methods Forty maxillary canine teeth were decoronated, underwent endodontic treatment, and were stored in an incubator for 7 days. After post space preparation, the teeth were randomly divided into four groups for different surface treatments: (I) saline, (II) 17% EDTA, (III) CAAP, and (IV) 17% EDTA + CAAP. Fiber posts (Whitepost no. 2, FGM) were cemented into the root canals using Panavia F2.0 resin cement, and 1 mm-thick sections were made at the coronal, middle, and apical thirds of the roots. The samples underwent micro-push-out bond strength test. The mode of failure was also determined under a stereomicroscope. Data were analyzed using three-way ANOVA and Tukey's post hoc test (α = 0.05). The mode of failure data were analyzed using the chi-square test. Results The mean micro-push-out bond strength of fiber posts was not significantly different in the four groups (P > 0.05). However, the bond strength values in the coronal third were significantly higher than the corresponding values in the apical third (P=0.01). There was no significant difference in the modes of failure between the groups (P > 0.05). Conclusion Application of CAAP alone or in combination with 17% EDTA could not successfully increase the bond strength of fiber posts to root canal dentin.

Follow-Up after Cold Atmospheric Argon Plasma for Wound Management of Driveline Infections - A Promising Strategy

Follow-Up after Cold Atmospheric Argon Plasma for Wound Management of Driveline Infections - A Promising Strategy

Plasma medicine and wound management: Evaluation of the antibacterial efficacy of a medically certified cold atmospheric argon plasma jet

Objectives: A major problem for wound healing is contamination with bacteria, often resulting in biofilm formation and wound infection, which, in turn, needs immediate intervention such as surgical debridement and through irrigation. A topical treatment with cold atmospheric pressure plasma (CAP) for wound disinfection may present an alternative and less painful approach.Methods: This study investigated the antibacterial effects of a cold atmospheric pressure argon plasma jet (kINPen® MED) as a CAP source, using the three-dimensional Staphylococcus aureus immunocompetent biofilm system hpBIOM in addition to a standard planktonic test. Furthermore, skin cell compatibility was evaluated using a keratinocyte (HaCat) model.Results: CAP treatment (0–240 s) followed by incubation (15, 120 min) within the CAP-treated media showed slight bactericidal efficacy under planktonic conditions but no effect on biofilms. However, indirect CAP treatment of keratinocytes performed under the same conditions resulted in a significant decrease in metabolic activity. Short CAP treatment and exposure time (30 s; 15 min) induced a slight increase in the metabolic activity; however, longer treatments and/or exposure times led to pronounced reductions up to 100%. These effects could partially be reversed by addition of catalase, indicating a dominant role of CAP-generated hydrogen peroxide.Conclusions: These results indicate that plasma treatment does not lead to the desired disinfection or significant reduction in the bacterial burden of Staphylococcus aureus in a wet milieu or in biofilms. Thus, treatment with CAP could not be recommended as a single anti-bacterial therapy for wounds but could be used to support standard treatments.

Experimental Studies on Physicochemical Parameters of Water Samples before and after Treatment with a Cold Atmospheric Plasma Jet and its Optical Characterization

Cold plasma-liquid interaction becomes a growing interdisciplinary area of research involving plasma physics, fluid science, and chemistry. Plasma-liquid interaction has gained more interest over the last many years due to its potential applications in different fields. Cold atmospheric plasma jet is an emerging technology for surface drinking water treatment to improve quality and surface modification that is chemical-free and eco-friendly. Cold plasma treatment of water samples results in changes in turbidity, pH, and conductivity and in the formation of reactive oxygen and nitrogen species (RONS). As a result, plasma-activated water has a different chemical composition than water and can serve as an alternative technique for microbial disinfection. CAPJ has been generated by a high voltage 5 kV and a high frequency 19.56 kHz power supply. The discharge has been characterized by an optical method. To characterize the cold atmospheric pressure argon plasma jet, discharge plume temperature, and electron rotational and vibrational temperature have been determined. Cold atmospheric argon plasma jet produced at atmospheric condition contains high energetic electrons, ions, UV radiation, reactive oxygen, and nitrogen species named as cold plasma which has a wide range of applications in the biomedical industry, as well as in water treatment. Nowadays, researches have been carried out on ozonation through plasma jet interaction with surface drinking water. In this paper, we compare the change in physical and chemical parameters of surface water used for drinking purposes. The significant change in the physical parameters such as pH, turbidity, and electrical conductivity was studied. In addition, the significant changes in the concentration and absorbance of nitrate, ferrous, and chromium ions with respect to treatment time were studied. Our results showed that plasma jet interaction with surface drinking water samples can be useful for the improvement of water quality and an indicator for which reactive species play an important role in plasma sterilization.

Investigation on Parameters of Atmospheric Pressure Plasma Jet by Electrical and Optical Methods

The atmospheric pressure plasma jet works under atmospheric pressure condition, has been developed for surface treatment and biomedical applications. The produced jet has been characterized by electrical and optical methods. To characterize cold atmospheric argon plasma discharge, its electron density, and electron energy (temperature) at various conditions have been estimated by using different techniques such as power balance, stark broadening, and intensity ratio methods respectively. Atmospheric pressure plasma jet (APPJ) has drawn much attention all over the world due to its applications in material processing, biomedical material processing, and thin film deposition. APPJ has been produced, using a high voltage and high frequency power supply (0-20 kV) and an operating frequency of 20 kHz. Results showed that the electron density was of the order of 1014 cm-3 and 1016 cm-3 as determined by power balance, intensity ratio, and stark broadening methods respectively while electron temperature was estimated to be about 0.46 eV and 0.53 eV at 3 kV and 4 kV respectively by using intensity ratio method. The energy dissipation per cycle of the discharge was also estimated by using the Lissajous figure method. Our results confirmed that the parameter such as electron temperature and density depend on the applied voltage, gas flow rate, and electrode distance as well.

Enhanced Electrospinning of Active Organic Fibers by Plasma Treatment on Conjugated Polymer Solutions.

Realizing active, light-emitting fibers made of conjugated polymers by the electrospinning method is generally challenging. Electrospinning of plasma-treated conjugated polymer solutions is here developed for the production of light-emitting microfibers and nanofibers. Active fibers from conjugated polymer solutions rapidly processed by a cold atmospheric argon plasma are electrospun in an effective way, and they show a smoother surface and bead-less morphology, as well as preserved optical properties in terms of absorption, emission, and photoluminescence quantum yield. In addition, the polarization of emitted light and more notably photon waveguiding along the length of individual fibers are remarkably enhanced by electrospinning plasma-treated solutions. These properties come from a synergetic combination of favorable intermolecular coupling in the solutions, increased order of macromolecules on the nanoscale, and resulting fiber morphology. Such findings make the coupling of the electrospinning method and cold atmospheric plasma processing on conjugated polymer solutions a highly promising and possibly general route to generate light-emitting and conductive micro- and nanostructures for organic photonics and electronics.

Measuring the air fraction and the gas temperature in non-thermal argon plasma jets through the study of the air influence on the collisional broadening of some argon atomic emission lines

Cold atmospheric argon plasma jets have shown to be very promising in medicine and they are being currently used for therapeutical uses such as the healing of wounds or the treatment of tumors. Because they run in the open atmosphere, they generate copious amounts of reactive oxygen and nitrogen species, which play an outstanding role in their biological action. But, in this kind of reactor, unknown amounts of air enter the plasma region depending on the experimental conditions, changing the chemistry in them, and eventually their effects. In this work, we propose a new spectroscopic method to measure the amount of air in argon non-thermal (including cold atmospheric) plasma jets through the collisional broadening of Ar I 840.86 and Ar I 842.46 nm emission lines. The method allows the simultaneous determination of the gas temperature. For validation purposes, it was applied to a microwave-induced plasma jet working at different operational conditions. Results were consistent with those obtained from the rotational temperature derived from simulations of N2 (2nd positive system) rovibrational band.

Wound Management of Driveline Infections with Cold Atmospheric Argon Plasma - Proof of Concept

Driveline associated infections (DLI) are common in patients supported with ventricular assist devices (VAD). Patients with infections and wound healing disorder are often hospital bound and morbidity and mortality are elevated. The risk for severe bloodstream infection is high as foreign material colonization and multiresistant pathogen are omnipresent. Furthermore, DLI represent an imminent threat to survival and outcome after heart transplantation. Previous studies on the antimicrobial activity of cold atmospheric pressure argon plasma (CAP) showed promising effects against a wide range of pathogens in other fields. This is the first study to analyze the safety and efficiency of CAP in the treatment of DLI. Between 04/2019 and 09/2019 15 male patients with DLI were included. 5 patients with a HVAD and 10 patients with a HeartMate3 LVAD. Bacterial species were detected by standard bacterial swabs. 4 patients were treated in our outpatient VAD clinic. Concomitant antibiotic treatment was administered according to wound swabs. Analysis of 120 CAP treatments in 15 patients for DLI was performed in addition to an extended wound care. The average number of CAP sessions was 7.7 (1-17 sessions/patient). We found a reduction of bacterial load in treated wounds in 9 patients, regardless of the pathogen. The wounds were treated with a mean of 368.5 (120-480) seconds CAP in each session. There was a significant reduction in UTAH wound classification before and after CAP treatment (UTAH 2.80 vs. 1.18; p<0.001), as well as a significant reduction in wound size (16.08 vs. 1.90 cm3; p=0.047). The most common pathogen was staphylococcus aureus, in 8 patients. No adverse effects occurred, and treatment was well tolerated. CAP treatment is a potent, safe and painless supplemental technique to treat DLI without need for repeating surgical interventions. Further studies may support this pilot trial to evaluate details of the applied CAP and outcome measures need to be defined.

Interaction of Cold Atmospheric Argon and Helium Plasma Jets with Bio-Target with Grounded Substrate Beneath

The cold atmospheric pressure plasma jet interaction with the bio-target is studied in the plasma experiment, 2D fluid model simulations, and with MTT and iCELLigence assays of the viability of cancer cells. It is shown, for the first time, that the use of the grounded substrate under the media with cells considerably amplifies the effect of plasma cancer cell treatment in vitro. Plasma devices with cylindrical and plane geometries generating cold atmospheric plasma jets are developed and tested. The sequence of the streamers which forms the plasma jet is initiated with a voltage of 2.5–6.5 kV applied with the frequency 40 kHz. We suggest using the grounded substrate under the bio-target during the plasma jet treatment of cancer cells. The analysis of the measured plasma spectra and comparison of OH-line intensity for different voltages and gas flow rates allows us to find a range of optimal plasma parameters for the enhanced OH generation. The time-dependent viability is measured for human cell lines, A431 (skin carcinoma), HEK 293 (kidney embryonic cells), and A549 (human lung adenocarcinoma cells) after the plasma jet treatment. The results with cell-based experiments (direct treatment) performed with various plasma jet parameters confirm the maximum efficiency of the treatment with the optimal plasma parameters.

In vitro evaluation of the decontamination effect of cold atmospheric argon plasma on selected bacteria frequently encountered in small animal bite injuries

Beneficial effects of cold atmospheric argon plasma (CAAP) on wound healing and its capacity for bacterial decontamination has recently been documented. First, in vivo studies in small animals did not prove any decontamination effect in canine bite wounds. The present study evaluated the overall decontamination effect of CAAP for different bacteria frequently encountered in canine bite wounds with respect to growth phase, initial bacteria concentration and treatment duration.Standard strains of Escherichia (E.) coli, Staphylococcus (S.) pseudintermedius, S. aureus, Streptococcus (S.) canis, Pseudomonas (P.) aeruginosa and Pasteurella multocida were investigated. To evaluate the influence of the bacterial growth phase, each bacterium was incubated for three and eight hours, before CAAP treatment. Three different bacterial concentrations were created per bacterium and growth phase, and were exposed to CAAP for 30 s, 1 min and 2 min.CAAP treatment resulted in acceptable decontamination rates (range 98.9–99.9%) in all bacteria species in vitro; however, differences in susceptibility were detected. Decontamination rate was mainly influenced by initial bacterial concentration and treatment time. Growth phase only influenced decontamination in S. pseudintermedius. Treatment time significantly (P < .05) correlated with the decontamination rate in E. coli, S. canis and S. aureus, with an exposure time of 2 min being most effective. Initial bacterial concentration significantly (P < .05) influenced decontamination in Pasteurella multocida and P. aeruginosa, in which treatment time was not as important. CAAP exerts effective antibacterial activity against the tested bacteria strains in vitro, with species specific effects of treatment time, growth phase and concentration.

Cold atmospheric argon plasma jet source and its application for bacterial inactivation

In this work, the efficiency of inactivation of a cold argon plasma jet at atmospheric pressure (APPJ) on the basis of a low-current spark discharge into microorganisms with different characteristics of the cell walls was evaluated. Gram-negative bacteria Escherichia coli M17, gram-positive bacteria Bacillus subtilis 534 and Bacillus cereus IP 5832, and the yeast Saccharomyces cerevisiae were seeded on cultured Petri dishes. A plasma jet with an average power of 0.85 W and a flow rate of argon of 6.7 l/min was directed perpendicular to the Petri dishes with agar. The distance to the agar varied from 0.5 to 3 cm, and the treatment time varied from 5 to 300 s. The efficiency of inactivation was assessed by measuring the area of inactivation zones (where there was no growth of microorganisms). It was shown that gram-negative bacteria E. coli M17 is most susceptible to exposure to the plasma jet, and gram-positive bacteria B. cereus IP 5832 and yeast S. cerevisiae are most stable. It is established that an increase in the treatment time of plasma jets of a low-current spark allows effective inactivation of microorganisms over a much larger area.

Ferrous chloride and ferrous sulfate improve the fungicidal efficacy of cold atmospheric argon plasma on melanized Aureobasidium pullulans

Since cold atmospheric pressure plasma (CAP) has not only bactericidal activity but also fungicidal activity without toxic residues and thermal damage, it is considered as an alternative method for sterilization of fungi on the surfaces of perishable foodstuffs and human bodies. Aureobasidium pullulans is a ubiquitous yeast-like fungus and called black yeast because it produces melanin, a dark biological pigment. It is well known that various melanized fungi show hyper-resistance to extreme stress conditions including high levels of radioactivity. Curiously, however, there is very little information about the fungicidal effects of CAP on melanized fungi. Therefore, we herein investigated the effects of CAP on A. pullulans, using cold atmospheric argon plasma (Ar plasma). We found that ammonium sulfate repressed the synthesis of melanin in A. pullulans as well as Aureobasidium melanogenum. Although the non-melanized A. pullulans cells were efficiently killed by the exposure of Ar plasma, the melanized cells showed the significant resistance to Ar plasma as well as to hydrogen peroxide and thermal stress. In order to improve the fungicidal efficacy of Ar plasma, we examined the combination of Ar plasma and Fenton reaction. We realized that FeCl2 and FeSO4 significantly improved the sterilization efficacy of Ar plasma on the melanized A. pullulans.

Degradation of bromophenol blue molecule during argon plasma jet irradiation

The aim of this paper is to study degradation of a bromophenol blue molecule (C19H10Br4O5S) using direct irradiation of cold atmospheric argon plasma jet. The pH of the bromophenol blue solution has been measured as well as its absorbance spectra and conductivity before and after the irradiation of non-thermal plasma jet in various time durations. The results indicated that the lengths of conjugated systems in the molecular structure of bromophenol blue decreased, and that the bromophenol blue solution was decolorized as a result of the decomposition of bromophenol blue. This result shows that non-thermal plasma jet irradiation is capable of decomposing, and can also be used for water purification.

Investigation of toxicity and mutagenicity of cold atmospheric argon plasma.

Cold atmospheric argon plasma is recognized as a new contact free approach for the decrease of bacterial load on chronic wounds in patients. So far very limited data are available on its toxicity and mutagenicity on eukaryotic cells. Thus, the toxic/mutagenic potential of cold atmospheric argon plasma using the MicroPlaSter β® , which has been used efficiently in humans treating chronic and acute wounds, was investigated using the XTT assay in keratinocytes and fibroblasts and the HGPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 Chinese hamster cells. The tested clinical parameter of a 2 min cold atmospheric argon plasma treatment revealed no relevant toxicity on keratinocytes (viability: 76% ± 0.17%) and on fibroblasts (viability: 81.8 ± 0.10) after 72 hr as compared to the untreated controls. No mutagenicity was detected in the HGPRT assay with V79 cells even after repetitive CAP treatments of 2-10 min every 24 hr for up to 5 days. In contrast, UV-C irradiation of V79 cells, used as a positive control in the HGPRT test, led to DNA damage and mutagenic effects. Our findings indicate that cold atmospheric plasma using the MicroPlaSter β® shows negligible effects on keratinocytes and fibroblasts but no mutagenic potential in the HGPRT assay, indicating a new contact free safe technology. Environ. Mol. Mutagen. 58:172-177, 2017. © 2017 Wiley Periodicals, Inc.

Effect of voltage shape of electrical power supply on radiation and density of a cold atmospheric argon plasma jet

در این مقاله به تولید جت پلاسمای سرد فشار اتمسفری گاز آرگون با استفاده از روش تخلیه سد دی‌الکتریک با سه منبع توان الکتریکی با ولتاژ سینوسی، پالسی و دندان‌اره‌ای در بسامد یکسان 8 کیلوهرتز پرداختیم. ابتدا ویژگی مدار الکترونیک مورد نظر را برای تولید ولتاژ فشار قوی با شکل ولتاژ خروجی سینوسی، پالسی و دندان‌اره‌ای توضیح می‌دهیم. سپس اثر شکل ولتاژ اعمالی در شکست الکتریکی گاز بررسی می‌کنیم. غلظت نسبی گونه‌های فعال شیمیایی از جمله اکسیژن، نیتروژن اتمی، رادیکال هیدروکسیل به وسیله بیناب نمایی گسیل نوری اندازه‌گیری شد. همچنین با استفاده از یک مدل ساده نشان دادیم زمان برخاست کم موجب افزایش چگالی الکترون می‌شود بنابراین با توان الکتریکی مصرفی پایین‌تر می‌توان یک پلاسمای سرد تولید کرد.

Osteogenic Induction of Human Mesenchymal Stem Cells by Cold Atmospheric Argon Plasma

Osteogenic Induction of Human Mesenchymal Stem Cells by Cold Atmospheric Argon Plasma