Effect Of Atmospheric Pressure Plasma Research Articles

Контроль содержания металлов в составе биологических структур

The authors propose a monitoring method for defining metal content in the biological structures, such as plant leaves, tissue samples of animal origin, human skin, etc. The authors used dielectric barrier discharge (DBD) in air at atmospheric pressure as a diagnostic medium. According to the research, at the optimal selection of gas discharge parameters it will not have destructive effect on tissues of biological structure. Indeed, generation of chemically active particles in the plasma will be minimal one. The dielectric barrier separates the investigated sample from the electrode of the discharge system. DBD activation proceeds at frequencies close to the sound range (not more than 15 kHz). It was due to the requirement of ionic component emission only from cells on the surfaces of the structures under study. The conditions of low thermal effect of atmospheric pressure plasma on plant and animal sample provide the choice 
 of DBD frequency range.

Metal content monitoring in the biological structures

The authors propose a monitoring method for defining metal content in the biological structures, such as plant leaves, tissue samples of animal origin, human skin, etc. The authors used dielectric barrier discharge (DBD) in air at atmospheric pressure as a diagnostic medium. According to the research, at the optimal selection of gas discharge parameters it will not have destructive effect on tissues of biological structure. Indeed, generation of chemically active particles in the plasma will be minimal one. The dielectric barrier separates the investigated sample from the electrode of the discharge system. DBD activation proceeds at frequencies close to the sound range (not more than 15 kHz). It was due to the requirement of ionic component emission only from cells on the surfaces of the structures under study. The conditions of low thermal effect of atmospheric pressure plasma on plant and animal sample provide the choice 
 of DBD frequency range.

A promising method for promoting interfacial adhesion of aramid/rubber composite using atmospheric pressure plasma surface modification

AbstractToday, aramid fibers are well known as a high‐performance and ideal material for reinforcement purposes in rubber product manufacturing including hoses, tires, cables, and conveyors composites. However, surface modification of aramid fiber is necessary to solve poor interfacial adhesion between aramid fibers and the rubber matrix. Accordingly, in the present study, the effect of the surface modification of aramid fibers using atmospheric pressure plasma treatment with different precursors on adhesion to the rubber matrix was investigated. For that, the plasma coating was conducted using argon as the main working gas, and toluene, acetonitrile, tetraethyl orthosilicate (TEOS), and hexamethyldisiloxane (HMDSO) as liquid precursors. The physical–chemical characterization of the layer confirmed the successful deposition of amorphous carbon, amorphous nitride‐carbon, SiO2, and Polydimethylsiloxane (PDMS)‐like coating layers on the surface of aramid fibers by using toluene, acetonitrile, TEOS, and HMDSO as precursors, respectively. Overall, the result showed that the plasma surface modifications with acetonitrile precursor leads to the increase in interfacial adhesion of aramid/rubber composite, while retaining the tensile strength, and flame resistance properties of aramid as original fibers. Notably, the results of this study confirm the potential use of atmospheric pressure plasma for surface modification of aramid yarn to produce functional aramid for use in rubber composites.Highlights The plasma‐coated aramid using HMDSO, TEOS, toluene, and acetonitrile precursors was prepared; and its effect on the tensile properties of aramid fiber as well as interfacial adhesion between aramid/rubber composite was investigated. The positive effect of atmospheric pressure plasma coating using HMDSO precursor on the tensile properties of aramid fiber was revealed. The positive effect of atmospheric pressure plasma coating using toluene and acetonitrile on the interfacial adhesion between aramid/rubber composite was revealed. The positive effect of atmospheric pressure plasma coating using TEOS precursor on the flam resistance property of aramid fiber was revealed. This study provides valuable insights into the effect of the different plasma‐coated organosilicon and hydrocarbon precursors on the interfacial adhesion between aramid/rubber composite.

Atmospheric Pressure Plasma Jet Exposure of Polylactic Acid Surfaces for Better Adhesion: Plasma Parameters towards Polymer Properties.

Polymers play a crucial role in multiple industries; however, surface modification is necessary for certain applications. Exposure to non-thermal plasma provides a viable and environmentally beneficial option. Fused deposition molding utilizes biodegradable polylactic acid, although it encounters constraints in biomedical applications as a result of inadequate mechanical characteristics. This study investigates the effects of atmospheric pressure plasma generated by a dielectric barrier discharge system using helium and/or argon on the modification of polylactic acid surfaces, changes in their wettability properties, and alterations in their chemical composition. The plasma source was ignited in either He or Ar and was tailored to fit the best operational conditions for polymer exposure. The results demonstrated the enhanced wettability of the polymer surface following plasma treatment (up to 40% in He and 20% in Ar), with a marginal variation observed among treatments utilizing different gases. The plasma treatments also caused changes in the surface topography, morphology, roughness, and hydrophilicity. Plasma exposure also resulted in observable modifications in the dielectric characteristics, phase transition, and structure. The experimental findings endorse the utilization of plasma technologies at normal air pressure for environmentally friendly processing of polymer materials, specifically for applications that necessitate enhanced adhesion and have carefully selected prerequisites.

Enhancing adhesion strength via synergic effect of atmospheric pressure plasma and silane coupling agent

To facilitate the widespread use of carbon fiber reinforced thermoplastic polymer (CFRTP), enhancing its adhesion strength with other materials is crucial. In this study, we investigated the synergic effect and underlying mechanism of atmospheric pressure plasma and silane coupling agent on the adhesion improvement of CFRTP. The plasma/mercapto-silane-treated CFRTP demonstrated a remarkable 282% increase in adhesion strength compared to untreated CFRTP. Our post-fracture analysis revealed that the weakest CFRTP/adhesive interface was fortified, resulting in a shift in the failure mode from adhesive to substrate. Equipment analyses indicated that plasma and silane coupling agent contributed to the formation of C-O and Si-O-Si linkages, respectively. The application of both treatments led to the creation of a macro-network at the CFRTP/adhesive interface through both linkages, which resulted in a much more substantial increase in adhesion strength than either treatment alone. Lastly, we propose guidelines for enhancing the adhesion strength of CFRTP by elucidating the dependence of the synergic or antagonistic effect on the organofunctional group in silane coupling agent.

Atmospheric pressure plasma treatment of chitosan-acrylic acid blends

This study explores the effect of atmospheric pressure plasma (APP) treatment on chitosan-acrylic acid (Cs-AA) blends. The experiment involves a custom-built APP setup used to modify a polymeric blend composed of natural (Cs) and synthetic (AA) polymers. Even with a low process temperature (<40 °C), reactive oxygen and nitrogen species (RONS) were observed in an air plasma plume. The interaction of plasma with the liquid surface was also observed. With de-ionized water as the test liquid, the operating parameters such as the treatment time and flow rate were shown to influence the pH and absorption spectrum of the liquid. The presence of RONS was investigated using optical emission spectroscopy coupled with principal component analysis. The analysis revealed that the air plasma contains the different N systems, NO, OH, H α, monatomic N, and monatomic O species. Varying the gas flow rate influences the production of NO and OH radicals while measuring plasma discharge in different conditions (ambient air, DI H 2O, Cs, and Cs-AA blend) affects the concentration of the N positive and negative systems. The effect of these RONS on the Cs-AA blends was also investigated by assessing the chemical structure, pH, and viscosity of the solution. In correlation with all of the findings, it was observed that plasma treatment could degrade pure Cs solution by dehydrogenation and glycosidic bond cleaving. However, the addition of AA reduces the degradation so that the AA radicals created by plasma form a complex with the Cs that reduces Cs fragmentation and chain entanglement, as observed in the reduction of viscosity. In summary, the rich reactive species created by plasma in the Cs-AA solution not only provided stable species but also introduced more Cs-AA complexes.

Effect of Atmospheric-Pressure Plasma on Functional Compounds and Physiological Activities in Peanut Shells.

Peanut (Arachis hypogaea L.) shell, an abundant by-product of peanut production, contains a complex combination of organic compounds, including flavonoids. Changes in the total phenolic content, flavonoid content, antioxidant capacities, and skin aging-related enzyme (tyrosinase, elastase, and collagenase)-inhibitory activities of peanut shell were investigated after treatment in pressure swing reactors under controlled gas conditions using surface dielectric barrier discharge with different plasma (NOx and O3) and temperature (25 and 150 °C) treatments. Plasma treatment under ozone-rich conditions at 150 °C significantly affected the total phenolic (270.70 mg gallic acid equivalent (GAE)/g) and flavonoid (120.02 mg catechin equivalent (CE)/g) contents of peanut shell compared with the control (253.94 and 117.74 mg CE/g, respectively) (p < 0.05). In addition, with the same treatment, an increase in functional compound content clearly enhanced the antioxidant activities of components in peanut shell extracts. However, the NOx-rich treatment was significantly less effective than the O3 treatment (p < 0.05) in terms of the total phenolic content, flavonoid content, and antioxidant activities. Similarly, peanut shells treated in the reactor under O3-rich plasma conditions at 150 ℃ had higher tyrosinase, elastase, and collagenase inhibition rates (55.72%, 85.69%, and 86.43%, respectively) compared to the control (35.81%, 80.78%, and 83.53%, respectively). Our findings revealed that a reactor operated with O3-rich plasma-activated gas at 150 °C was better-suited for producing functional industrial materials from the by-products of peanuts.

Effects of Atmospheric Pressure Plasma in the Treatment of Experimental Periodontitis in Beagle Dogs.

The specific objective of this study was to evaluate the effects of atmospheric pressure plasma (APP) in the treatment of experimental periodontitis in Beagle dogs. The APP jet was diagnosed using optical emission spectroscopy and laser-induced fluorescence spectroscopy. Six Beagles received stainless steel ligatures to establish experimental periodontitis model. The teeth in the control group were subjected to conventional root surface debridement (RSD) and chlorhexidine irrigation. The APP group also started with RSD and was then subjected to plasma irradiation. Clinical analyses including plaque index, modified sulcus bleeding index, pocket depth and attachment loss (AL), as well as cone-beam computed tomography (CBCT) analysis, were performed at baseline, 4th week, 8th week and 12th week after treatment. The results showed that typical reactive oxygen and nitrogen species were found in the full spectrum and the gas temperature of APP was close to room temperature. The highest concentrations of hydroxide and oxygen were obtained at 5 mm away from the nozzle. In both groups, all values in clinical examinations were significantly lower (P<0.05) at 12th week after treatment than those at baseline. At the 12th week, the AL in clinical examinations and the bone loss in CBCT images in the APP group were significantly lower than those in the control group (P<0.05). The hematoxylin-eosin staining showed more renascent alveolar bone in the APP group than in the control group. These findings suggested that APP has profound potential for use as an adjunct approach for periodontitis treatment.

The Therapeutic Effect of Atmospheric Pressure Plasma on Ultraviolet B-Induced Skin Photoaging and Damage in Mice

The active substances produced by atmospheric pressure plasma jet (APPJ) have biomedical effects such as disinfection, proliferation, anticancer, and wound healing. Plasma has been applied in dermatology; however, the mechanism of APPJ on ultraviolet B (UVB) induced skin photoaging and damage has not been widely investigated. In this study, we developed an APPJ device that is capable of generating plasma in open spaces and acting on biological surfaces. We then studied the effects of the APPJ application on UVB-induced skin photoaging and damage in mouse models. The results showed that APPJ prevented the degradation of collagen and elastin by decreasing the secretion of matrix metalloproteinases (MMPs). We also found that after the APPJ treatment, the density of the extracellular matrix (ECM) was maintained, the skin roughness caused by the UVB was decreased, and the epidermal and dermal thickness was improved. Molecular analysis of the skin tissue revealed that APPJ prevented UVB-induced apoptosis through p53, Caspase-8, caspase-9, and Bax in the pro-apoptotic pathway and Bcl-2 in the anti-apoptosis pathway and eventually reduced the expression of Caspase-3. In conclusion, APPJ application could protect skin against UVB-induced photoaging and damage, demonstrating its potential as a new therapeutic method for skin conditions.

Effect of Atmospheric Pressure Plasma in Inert Gases on Orthopedic Ultra-High Molecular Weight Polyethylene

In this work, studies have been conducted on the treatment of ultrahigh molecular weight polyethylene (UHMWPE), which is one of the structural materials used in the endoprostheses, with atmospheric pressure plasma in high-purity argon and helium. For this purpose, an installation consisting of a high-voltage pulsed generator, voltage and current measuring devices and a reaction quartz chamber with electrodes, in which UHMWPE samples were placed, was developed and constructed. It is shown that processing under certain conditions in Ar plasma and He at atmospheric pressure leads to the appearance of terminal double bonds in the structure of the processed polyethylene, as evidenced by the appearance of a peak of 880 cm-1, in the attenuated total reflection IR spectrum. This peak is observed both for samples treated in helium and argon plasma. The formation of such bonds is a consequence of the generation of active radicals in the UHMWPE surface layer under plasma treatment, which, during recombination, also form intermolecular crosslinking, thereby increasing the strength characteristics of the material as a whole. The modification of the surface of the treated samples begins within the first minute of processing and reaches its peak values 10-20 minutes after treatment in plasma.

Mechanisms of atmospheric pressure plasma protection of neuronal cells under simulated ischemic stroke conditions

Physico-chemical and biological effects of atmospheric pressure plasmas (APPs) find numerous applications in biotechnology, medicine, and other fields. Recent studies revealed APPs’ potential for ischemic stroke treatment through the protection of neuronal cells from injuries. However, the mechanisms of the plasma neuroprotection effects still remain unknown. This study reveals the key mechanisms of APP plasma jet (APPJ) enabled reduction of neuronal cell death caused by oxygen and glucose deprivation (OGD) under stroke-relevant conditions. Plasma reduced OGD induced apoptosis of SH-SY5Y neuronal cells is based on reactive oxygen and nitrogen species production and on nitric oxide related activation of the cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase G (PKG) pathway, followed by the Bcl-2/Bax level modulation and caspase3/9 activity inhibition. In addition, the protective effect of APPJ treatment on OGD injured SH-SY5Y cells could be abolished by cGMP pathway inhibitor LY83583 pretreatment. Collectively, our findings highlight that the mechanism of the neuroprotection effects of the plasma treatment is closely related to the intracellular cGMP/PKG pathway, which provide experimental and theoretical references for future studies on plasma medicine.

Effect of argon plasma on repair bond strength using nanofilled and microhybrid composites.

To evaluate the effect of atmospheric pressure plasma (PLA), sandblasting (SAN), silanization (SIL) and hydrophobic bonding resin (HBR) on the micro-shear bond strength (MSBS) of fresh nanofilled (NF) or microhybrid (MH) composites to water-aged nanofilled composite. NF plates were fabricated and stored in distilled water for 4 months. The aged plates were assigned to the groups (n=6): 1- untreated; 2- SAN + SIL + HBR; 3- HBR; 4- PLA + HBR; 5- SAN + HBR; 6- SAN + PLA + HBR; and 7- PLA. Two fresh composite cylinders were constructed on each plate with NF or MH composites and tested after 24 h or 1year of water-storage, using the MSBS testing. Data were analyzed by three-way ANOVA and Tukey test (α=0.05). NF yielded better outcomes than MH at 24 h, which was not observed at 1 year. HBR showed the highest MSBS results, while untreated and PLA groups yielded the lowest one. MSBS reduced for all groups after 1 year. Only HBR can obtain good MSBS results, while PLA alone was not beneficial. After 1 year, a reduction in repair MSBS was observed and the type of composite did not influence the results. The repair technique can be simplified with the use of only an adhesive and macromechanical retentions in the old composite, regardless the type of fresh composite.

A Dielectric Barrier Discharge Plasma Degrades Proteins to Peptides by Cleaving the Peptide Bond

Effects of atmospheric pressure plasmas on proteins are studied to assess the quality of plasma decontamination and to gain insights into plasma-triggered molecular events underlying observations made in plasma medicine on the cellular, organ, and systemic level. Atmospheric pressure plasma treatment has been reported to cause protein degradation. Degradation products, however, have not been characterized. Treating different model proteins in aqueous solution with a DBD plasma, we confirmed with different methods (Bradford assay, application of Lambert–Beer’s law on absorption measurements at 280 nm, ninhydrin assay, size exclusion chromatography, SDS-PAGE) that protein degradation takes place. Peptides of different sizes were detected by size exclusion chromatography. The ninhydrin assay indicated that peptide bonds are cleaved. In the presence of hydroxyl radical scavenger d-mannitol, the concentration of amino termini formed during the initial 10 min of plasma treatment was reduced by 96%, while at longer treatment times mannitol did no longer prevent the formation of amino termini, indicating that hydroxyl radicals play an important role in the initial cleaving of peptide bonds in the protein, but other mechanisms are at play in cleaving the peptide bonds in the resulting peptides. The generation of peptides has implications for plasma decontamination and plasma medicine. It is critical to verify that plasma decontamination processes do not result in protein fragments with undesired properties. In plasma medicine, plasma-generated protein fragments may act as molecular triggers in treated cells, tissues, or patients, e.g., regulating signaling cascades in a protease-like fashion.

The effect of plasma treatment on the surface chemistry and structure of ZnMgAl coatings

A principal investigation on the effect of atmospheric pressure plasma on Zn1.5Mg2.5Al coating was performed by means of X-ray photoelectron- and Auger electron spectroscopy as well as by transmission electron microscopy. The type of the medium used to generate the plasma influenced significantly the impact of the proceeded treatment. Although a mild surface cleaning and oxidation effect was observed for air, N2 or H2O plasma, mixed air + H2O and N2 + H2O plasma types already caused a remarkable altering of the chemical composition, structure and thickness of the coating surface layer, a similar effect to an initial corrosion attack.

Effect of atmospheric pressure plasma on surface modification of paper

A study of plasma treatment of clay-coated paper is presented. The wettability of the paper surface before and after the plasma treatment was determined by measuring the water contact angle and surface free energy. The appearance of the surface-functional groups was determined by using high-resolution X-ray photoelectron spectroscopy, while changes in the surface morphology were monitored by scanning electron microscopy. Already after 0.25 s of the plasma treatment, the paper surface improved its wettability. The X-ray photoelectron spectroscopy analyses showed a gradual increase of oxygen-rich functional groups on the surface while scanning electron microscopy analyses did not show a significant modification of the morphology and no alternation of the surface structure after the plasma treatment.

Optimization and influence of multi-hollow surface dielectric barrier discharge plasma operating conditions on the physical quality of peanut

An experiment was conducted to investigate the effects of atmospheric pressure plasma generated by multi-hollow surface dielectric barrier discharges on physical quality of peanut (Arachis Hypogea L). Multi-hollow surface dielectric barrier discharge is a novel plasma device applicable in food industry applications due to the capacity of the generated plasma to treat the surface of food without changing the quality. Response surface methodology was used to optimize the plasma treatment for surface treatment as raw peanut forms over a range of power (10–40 W), air flow rate (0.5–20 L/min) and time (1–15 min). The weight loss, hardness, contact angle, color parameters, microstructure, and sensory quality evaluation were evaluated during plasma treatments and modeled by response surface methodology and compared the means. Second order polynomial model adequately described the plasma treated experimental data except for sensory attributes with an insignificant lack of fit (p > 0.05). The result revealed that extreme conditions caused a decrease in L*,b*, hardness, contact angle, increased weight loss, color change and changed the microstructure of the treated peanuts.

Effect of Atmospheric Pressure Plasma on Listeria monocytogenes Attached to Abiotic Surfaces

Listeria monocytogenes can be introduced into food processing plants via raw material of animal or plant origin and can establish endemic populations through formation of biofilms. Biofilms are a continuous source of contamination for food products, and L. monocytogenes cells in biofilms are more resistant to stress and sanitizing agents than are planktonic cells. The use of gas-discharge plasmas may offer a feasible alternative to conventional sanitization methods. Plasmas are a mixture of charged particles, chemically reactive species, and UV radiation and can be used to destroy microorganisms. The purpose of this study was to measure the effectiveness of cold atmospheric pressure plasma (APP) treatments against bacteria attached to a solid surface and to evaluate the individual susceptibility of various L. monocytogenes strains. Attention was focused on the state of the cells after treatment, combining detection by viable counts and quantitative PCR (qPCR). Most of the culturable cells were inactivated after APP treatment, but the qPCR assay targeting the 16S rRNA revealed the presence of injured cells or their entrance into the viable but nonculturable state. These results were at least partly confirmed by a resuscitation experiment. After APP treatment, L. monocytogenes cell suspensions were incubated in brain heart infusion broth; some cells grew in the medium and therefore had survived the treatment. An understanding of the effects of APP on L. monocytogenes can inform the development of sanitation programs incorporating APP for pathogen removal. Methods other than those based of the culturability of the cells should be used to monitor pathogens in food processing plants because cultivation alone may underestimate the actual microbial load.

Effects of Multihollow Surface Dielectric Barrier Discharge Plasma on Chemical and Antioxidant Properties of Peanut

An experiment was conducted to investigate the effects of atmospheric pressure plasma generated by multihollow surface dielectric barrier discharge on chemical and antioxidant properties of peanut. Multihollow surface dielectric barrier discharge is a novel plasma device applicable in food industry applications due to the capacity of the generated plasma to treat the surface of food without changing the quality. Peanut seeds were exposed to the multihollow plasma for different plasma power (10–40 W), air flow rate (0.5–20 l/min), and time (1–15 min). The fatty acid profile, peroxide value, acid value, moisture content, total polyphenols, and antioxidant activity were evaluated during cold plasma treatment. The result revealed that, due to the variation plasma power, treatment time and air flow rate caused a decrease in unsaturated fatty acid and moisture content and increased saturated fatty acids, peroxide value, acid value, and total polyphenols of the peanut.

Hemoglobin as a Diagnosing Molecule for Biological Effects of Atmospheric-Pressure Plasma

The studies with proteins are necessary to understand the biological effects of atmospheric pressure plasma (APP). Among proteins, those with transient metal ions play key roles in many biological events and they are very sensitive to environmental redox states. Iron-containing hemoglobin (Hb) is investigated in this study, after APP treatments under two environmental gas conditions of pure N2 and N2 + O2 mixture. Monitoring the intensity change for absorption spectra could lead to a quantitative assessment of the effect of discharge plasma on Hb. Redox states of Hb are classified into five states including O2-bound Hb (oxy-Hb), deoxy-Hb, met-Hb, NO-bound Hb (NO-Hb), and hemichrome. Chemically generated reactive species and some scavengers are applied to understand the chemical reactions. Our experimental results confirm the complex chemical reactions of APP and suggest the possible use of Hb as a model protein for the visualization of APP biological effects.

PR491: The effect of atmospheric pressure plasma on wound healing following gingivectomy operation: case series

PR491: The effect of atmospheric pressure plasma on wound healing following gingivectomy operation: case series