scholarly journals Influence of Nonthermal Atmospheric Plasma-Activated Water on the Structural, Optical, and Biological Properties of Aspergillus brasiliensis Spores

2020 ◽  
Vol 10 (18) ◽  
pp. 6378
Author(s):  
Se Hoon Ki ◽  
Hyeongjin Noh ◽  
Geum Ran Ahn ◽  
Seong Hwan Kim ◽  
Nagendra K. Kaushik ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fungal Spores ◽  
Plasma Jet ◽  
Biological Properties ◽  
Atmospheric Plasma ◽  
Air Plasma ◽  
Activation Time ◽  
Aspergillus Brasiliensis ◽  
Plasma Activation ◽  
Plasma Activated Water

Plasma-activated water (PAW) has emerged as a platform for sterilizing fungal pathogens. In this study, we investigated the influence of PAW on black melanized spores of Aspergillus brasiliensis to explore the mechanism of fungal spore inactivation. PAW was prepared by activating deionized water with a nonthermal atmospheric pressure air plasma jet (soft plasma jet). The concentrations of H2O2 and NOx in the PAW treated by the soft plasma jet for 3 min were 50 μM and 1.8 mM, respectively, and the pH of the PAW was 3.10. The reactive oxygen and nitrogen species (RONS) in the PAW increased with longer plasma activation time. After being treated for 30 min in the PAW with a plasma activation time of 3 min, the spore viability dramatically dropped to 15%. The viabilities of 0.3% H2O2- and 0.3% HNO3-treated spores were 22% and 42%, respectively. The breakage of the spore cell wall by the PAW was revealed in scanning electron microscope images and flow cytometry measurements. Disruption of cell wall integrity provides a path for intracellular components to escape and RONS of the PAW can attack intracellular components directly. Degradation of high molecular genomic DNA was also observed by agarose gel electrophoresis. These results suggest that long-lived reactive species generated in the PAW play an important role in the inactivation of melanized fungal spores. Consequently, PAW produced by a soft plasma jet can be applied to sterilize bioprotective walled fungal spores in a relatively large volume.

scholarly journals Structural Changes of Hydroxylapatite during Plasma Spraying: Raman and NMR Spectroscopy Results

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 987
Author(s):  
Robert B. Heimann
Keyword(s):  
Plasma Spraying ◽  
Structural Changes ◽  
Plasma Jet ◽  
Biological Properties ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Decomposition Reactions ◽  
Laser Raman ◽  
Hot Plasma ◽  
Crystallographic Symmetry

Functional osseoconductive coatings based on hydroxylapatite (HAp) and applied preferentially by atmospheric plasma spraying to medical implant surfaces are a mainstay of modern implantology. During contact with the hot plasma jet, HAp particles melt incongruently and undergo complex dehydration and decomposition reactions that alter their phase composition and crystallographic symmetry, and thus, the physical and biological properties of the coatings. Surface analytical methods such as laser-Raman and nuclear magnetic resonance (NMR) spectroscopies are useful tools to assess the structural changes of HAp imposed by heat treatment during their flight along the hot plasma jet. In this contribution, the controversial information is highlighted on the existence or non-existence of oxyapatite, i.e., fully dehydrated HAp as a thermodynamically stable compound.

scholarly journals Spore Viability and Cell Wall Integrity of Cordyceps pruinosa Treated with an Electric Shock-Free, Atmospheric-Pressure Air Plasma Jet

2019 ◽  
Vol 9 (18) ◽  
pp. 3921 ◽  
Author(s):  
Noh ◽  
Kim ◽  
Kim ◽  
Kim ◽  
Han ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Electric Shock ◽  
Atmospheric Pressure ◽  
Plasma Jet ◽  
Reactive Species ◽  
Cell Wall Integrity ◽  
Air Plasma ◽  
Spore Viability ◽  
Spore Cell

Atmospheric-pressure Ar plasma jets are known to be detrimental to Cordyceps pruinosa spores. However, it is not clear what kinds of reactive species are more effective with regard to fungal cell death. Herein, we study which reactive species plays pivotal roles in the death of fungal spores using an electric shock-free, atmospheric-pressure air plasma jet, simply called soft plasma jet. Plasma treatment significantly reduced the spore viability and damaged fungal DNA. As observed from the circular dichroism spectra, scanning electron microscope images, and flow cytometric measurements, cell wall integrity was decreased by reactive oxygen and nitrogen species (RONS) from the plasma itself and the plasma-activated water. Consequently, degradation of the spore cell wall allows RONS from the plasma to reach the intracellular components. Such plasma-induced intracellular RONS can attack spore DNA and other intracellular components, as confirmed by electrophoresis analysis and phosphorylated histone measurement. In addition, weakening of the spore cell wall allowed for the loss of intracellular components, which can lead to cell death. Plasma radicals were investigated by measuring the optical emission spectrum of the soft plasma jet, and intracellular reactive oxygen species were confirmed by measuring the fluorescence of 2′, 7′-dichlorodihydrofluorescein-diacetate (H2DCF-DA)-stained spores. The soft plasma jet generated considerable amounts of H2O2 and NOx but a very small number of OH radicals as compared to the atmospheric-pressure Arplasma jet; this indicates that plasma-induced long-lived reactive species (H2O2 and NOx) play an important role in the weakening of spore cell walls and cell death.

scholarly journals Physicochemical Properties of Pure Water Treated by Pure Argon Plasma Jet Generated by Microwave Discharge in Opened Atmosphere

2021 ◽  
Vol 8 ◽  
Author(s):  
Konstantin F. Sergeichev ◽  
Natalya A. Lukina ◽  
Ruslan M. Sarimov ◽  
Igor G. Smirnov ◽  
Alexander V. Simakin ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Microwave Discharge ◽  
Pure Water ◽  
Argon Plasma ◽  
Surfactant Solution ◽  
Plasma Jet ◽  
Biological Properties ◽  
Oh Radicals ◽  
Nitrate And Nitrite ◽  
Plasma Activated Water

The physicochemical properties of water activated by high-purity low-temperature argon plasma of electrodeless microwave discharge at atmospheric pressure are investigated. Such parameters of activated water as electrical conductivity, redox potential, hydrogen index (pH), the concentrations of dissolved molecular oxygen, hydrogen peroxide, OH-radicals, nitrate and nitrite anions depending on the plasma jet distance above the water surface and duration of activation were studied. Under irradiation conditions close to optimum, it was shown that the generation rate in the absence of impurities are 200 μM/min for H2O2; 800 μM/min for •OH and 2 mM/min for NOx−. The use of plasma activated water (PAW) in agriculture has been tested. It was shown that strawberry seeds treated with a surfactant solution grow much faster than control seeds. The mechanisms of the chemical composition formation of activated water and its biological properties are discussed.

Activation of deionized water by atmospheric plasma jet in helium gas flow

2021 ◽  
Author(s):  
P. Y. Tan ◽  
O. H. Chin ◽  
R. Anpalagan ◽  
Y. T. Lau ◽  
H. C. Lee
Keyword(s):  
Gas Flow ◽  
Plasma Jet ◽  
Deionized Water ◽  
Atmospheric Plasma ◽  
Helium Gas

scholarly journals Tiny Cold Atmospheric Plasma Jet for Biomedical Applications

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 249
Author(s):  
Zhitong Chen ◽  
Richard Obenchain ◽  
Richard E. Wirz
Keyword(s):  
Biomedical Applications ◽  
Plasma Jet ◽  
Discharge Voltage ◽  
Plasma Jets ◽  
Atmospheric Plasma ◽  
Physical Parameters ◽  
Cold Atmospheric Plasma ◽  
Water Metal ◽  
Plasma Probe ◽  
Jet Nozzle

Conventional plasma jets for biomedical applications tend to have several drawbacks, such as high voltages, high gas delivery, large plasma probe volume, and the formation of discharge within the organ. Therefore, it is challenging to employ these jets inside a living organism’s body. Thus, we developed a single-electrode tiny plasma jet and evaluated its use for clinical biomedical applications. We investigated the effect of voltage input and flow rate on the jet length and studied the physical parameters of the plasma jet, including discharge voltage, average gas and subject temperature, and optical emissions via spectroscopy (OES). The interactions between the tiny plasma jet and five subjects (de-ionized (DI) water, metal, cardboard, pork belly, and pork muscle) were studied at distances of 10 mm and 15 mm from the jet nozzle. The results showed that the tiny plasma jet caused no damage or burning of tissues, and the ROS/RNS (reactive oxygen/nitrogen species) intensity increased when the distance was lowered from 15 mm to 10 mm. These initial observations establish the tiny plasma jet device as a potentially useful tool in clinical biomedical applications.

Sterilization of bacillus subtilis spores using an atmospheric plasma jet

2012 ◽  
Author(s):  
Jie Shen ◽  
Cheng Cheng ◽  
Shidong Fang ◽  
Hongbing Xie ◽  
Longwei Cheng ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Plasma Jet ◽  
Atmospheric Plasma

scholarly journals Plasma-Activated Water (PAW) as a Disinfection Technology for Bacterial Inactivation with a Focus on Fruit and Vegetables

Foods ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 166
Author(s):  
Aswathi Soni ◽  
Jonghyun Choi ◽  
Gale Brightwell
Keyword(s):  
Fruit And Vegetables ◽  
Atmospheric Plasma ◽  
Model Systems ◽  
Thermal Treatments ◽  
Bacterial Cells ◽  
Bacterial Inactivation ◽  
Gas Temperature ◽  
Bacterial Strains ◽  
Sensory Qualities ◽  
Plasma Activated Water

Plasma-activated water (PAW) is generated by treating water with cold atmospheric plasma (CAP) using controllable parameters, such as plasma-forming voltage, carrier gas, temperature, pulses, or frequency as required. PAW is reported to have lower pH, higher conductivity, and higher oxygen reduction potential when compared with untreated water due to the presence of reactive species. PAW has received significant attention from researchers over the last decade due to its non-thermal and non-toxic mode of action especially for bacterial inactivation. The objective of the current review is to develop a summary of the effect of PAW on bacterial strains in foods as well as model systems such as buffers, with a specific focus on fruit and vegetables. The review elaborated the properties of PAW, the effect of various treatment parameters on its efficiency in bacterial inactivation along with its usage as a standalone technology as well as a hurdle approach with mild thermal treatments. A section highlighting different models that can be employed to generate PAW alongside a direct comparison of the PAW characteristics on the inactivation potential and the existing research gaps are also included. The mechanism of action of PAW on the bacterial cells and any reported effects on the sensory qualities and shelf life of food has been evaluated. Based on the literature, it can be concluded that PAW offers a significant potential as a non-chemical and non-thermal intervention for bacterial inactivation, especially on food. However, the applicability and usage of PAW depend on the effect of environmental and bacterial strain-based conditions and cost-effectiveness.

Enhancement Propagation of Protocorms in Orchid (Cymbidium tracyanum L. Castle) by Cold Atmospheric Pressure Air Plasma Jet

2021 ◽  
Author(s):  
Sorapong Pavasupree ◽  
Nattapong Chanchula ◽  
Atipong Bootchanont ◽  
Chakkaphan Wattanawikkam ◽  
Pinit Jitjing ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Plasma Jet ◽  
Air Plasma
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