scholarly journals Parameters Affecting the Antimicrobial Properties of Cold Atmospheric Plasma Jet

2019 ◽  
Vol 8 (11) ◽  
pp. 1930 ◽  
Author(s):  
Bih-Show Lou ◽  
Chih-Ho Lai ◽  
Teng-Ping Chu ◽  
Jang-Hsing Hsieh ◽  
Chun-Ming Chen ◽  
...  
Keyword(s):  
Gas Flow ◽  
Treatment Time ◽  
Plasma Jet ◽  
Atmospheric Plasma ◽  
Gas Flow Rate ◽  
Cold Atmospheric Plasma ◽  
E Coli ◽  
Antimicrobial Efficiency ◽  
Ar Gas ◽  
Sample Distance

Using the Taguchi method to narrow experimental parameters, the antimicrobial efficiency of a cold atmospheric plasma jet (CAPJ) treatment was investigated. An L9 array with four parameters of CAPJ treatments, including the application voltage, CAPJ-sample distance, argon (Ar) gas flow rate, and CAPJ treatment time, were applied to examine the antimicrobial activity against Escherichia coli (E. coli). CAPJ treatment time was found to be the most influential parameter in its antimicrobial ability by evaluation of signal to noise ratios and analysis of variance. 100% bactericidal activity was achieved under the optimal bactericidal activity parameters including the application voltage of 8.5 kV, CAPJ-sample distance of 10 mm, Ar gas flow rate of 500 sccm, and CAPJ treatment time of 300 s, which confirms the efficacy of the Taguchi method in this design. In terms of the mechanism of CAPJ’s antimicrobial ability, the intensity of hydroxyl radical produced by CAPJ positively correlated to its antimicrobial efficiency. The CAPJ antimicrobial efficiency was further evaluated by both DNA double-strand breaks analysis and scanning electron microscopy examination of CAPJ treated bacteria. CAPJ destroyed the cell wall of E. coli and further damaged its DNA structure, thus leading to successful killing of bacteria. This study suggests that optimal conditions of CPAJ can provide effective antimicrobial activity and may be grounds for a novel approach for eradicating bacterial infections.

scholarly journals He-Plasma Jet Generation and Its Application for E. coli Sterilization

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Tiejian Liu ◽  
Yuxuan Zeng ◽  
Xin Xue ◽  
Yinyi Sui ◽  
Yingying Liang ◽  
...  
Keyword(s):  
Gas Flow ◽  
Treatment Time ◽  
Water Discharge ◽  
Atmospheric Pressure Plasma ◽  
Emission Spectra ◽  
Plasma Jet ◽  
Active Species ◽  
Short Treatment ◽  
Surface Sterilization ◽  
E Coli

Atmospheric pressure plasma jet (APPJ) is a promising technique for the sterilization of pathogenic microorganisms in an ambient environment. In this work, a helium-APPJ was generated by double dielectric barrier discharge and applied to the sterilization of model microorganism in air and water. Discharge characteristics (including waveform and frequency of applied voltage), jet properties (such as feed gas flow rate, jet length, thermal effect, and optic emission spectra), and sterilization performance (in terms of clear/sterilized area, size of plaques, and sterilization efficiency) were investigated. Homogeneous helium plasma jet was generated in an energy-efficient way (18 kHz, 6 kV, 0.08 W) with a 19 mm jet and limited heating. The He-APPJ achieved good sterilization performances within very short treatment time (as short as 30 s). For surface sterilization, the area of clear zone and size of the plaque were 1809 mm2 and 48 mm, respectively, within 5 min treatment. For water sterilization, 99.8% sterilization efficiency was achieved within 5 min treatment. The optic emission spectra suggest that active species such as excited molecules, ions, and radicals were produced in the He-APPJ. The as-produced active species played important roles in the sterilization process.

Evaluation of Solid Lubricant Coatings for Low Friction and Wear Resistance Using the Atmospheric Plasma Spray

2004 ◽  
Vol 449-452 ◽  
pp. 777-780 ◽  
Author(s):  
Chang Min Han ◽  
Han Shin Choi ◽  
Chang Hee Lee ◽  
Hyung Jun Kim ◽  
S.Y. Hwang
Keyword(s):  
Flow Rate ◽  
Friction And Wear ◽  
Gas Flow ◽  
Plasma Jet ◽  
Hydrogen Gas ◽  
Atmospheric Plasma ◽  
Dry Sliding Wear ◽  
Coating Properties ◽  
Gas Flow Rate ◽  
Jet Characteristics

A blended NiCr-Cr2O3-Ag-BaF2/CaF2 feedstock was sprayed using an atmospheric plasma spraying process. Due to the differences in physical and thermophysical properties of each constituent, coating microstructures and resulting coating properties were largely dependent on the interactions between each constituent phase and plasma jet in view of the physics of thermal spraying. Thus, hydrogen gas flow rate was changed to affect the plasma jet characteristics such as gas enthalpy and gas thermal conductivity in this study. According to it, evolutions of chemical composition and microstructures of the as-sprayed coatings were observed. As the hydrogen gas flow rate was increased, Cr2O3 weight fraction was increased with the decrease of Ag and porosity. Vickers microhardness and bond strength of the coatings showed consistent behaviors to the phase composition and microstructures. Friction coefficient and weight loss during a pin-on-disc dry sliding wear test were measured from room temperature to 500°C at the interval of 100°C. Finally, the effects of phase fraction and coating properties on the friction and wear were investigated.

scholarly journals Effect of plasma jet on the water and hydrogen peroxide that used for assisted teeth bleaching

2019 ◽  
Vol 15 (34) ◽  
pp. 29-35
Author(s):  
Hammad R. Humud
Keyword(s):  
Hydrogen Peroxide ◽  
Exposure Time ◽  
Power Supply ◽  
Gas Flow ◽  
Electrical Power ◽  
Plasma Jet ◽  
Liquid Temperature ◽  
Gas Flow Rate ◽  
High Voltage Power Supply ◽  
Ar Gas

In this work the interaction of plasma jet with water and hydrogen peroxide liquids used for assisted teeth bleaching by plasma jet had been study. A homemade plasma jet system was used. The plasma jet supply by 15 W electrical power generated by high voltage power supply of 9.6 kV peak to peak and frequency of 33 kHz .this power supply generate high electric field on electrodes that would be enough to ionize the argon gas. Some important agents were study such as the effect of the Ar gas flow rates on the length of the plasma jet, the influence of plasma jet on some properties of water and two hydrogen peroxide concentrations 25 % and 30 % like pH, conductivity and liquid temperature for different exposure time. The liquids temperature was measured by digital infrared thermometer, the gas flow rate were measured by gas flow meter, the pH, and the conductivity was measured by pH conductivity ultra-meter. The results illustrated that the conductivity and liquid temperature increase with increasing of exposure time. It can be conclude that the liquid properties were changed less than the boundaries that could affect adversely to the cells that located in the plasma jet.

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.

scholarly journals Heterogeneous Bonding of PMMA and Double-Sided Polished Silicon Wafers through H2O Plasma Treatment for Microfluidic Devices

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 580
Author(s):  
Chao-Ching Chiang ◽  
Philip Nathaniel Immanuel ◽  
Yi-Hsiung Chiu ◽  
Song-Jeng Huang
Keyword(s):  
Plasma Treatment ◽  
Flow Rate ◽  
Gas Flow ◽  
Treatment Time ◽  
Optical Emission ◽  
Microfluidic Devices ◽  
Oh Radicals ◽  
Gas Flow Rate ◽  
Oh Groups ◽  
Plasma Treatment Time

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H2O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H2O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e−) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H2O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H2O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e− bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices.

Human Mononuclear Cell Survival and Proliferation is Modulated by Cold Atmospheric Plasma Jet

2013 ◽  
Vol 10 (8) ◽  
pp. 706-713 ◽  
Author(s):  
Sander Bekeschus ◽  
Kai Masur ◽  
Julia Kolata ◽  
Kristian Wende ◽  
Anke Schmidt ◽  
...  
Keyword(s):  
Cell Survival ◽  
Mononuclear Cell ◽  
Plasma Jet ◽  
Atmospheric Plasma ◽  
Cold Atmospheric Plasma ◽  
Human Mononuclear Cell ◽  
Cell Survival And Proliferation

A Study on the Effect of Process Parameters on Surface Topography of Al Thin Films on Various Substrates Using AFM

2011 ◽  
Vol 383-390 ◽  
pp. 903-908
Author(s):  
S. Shanmugan ◽  
D. Mutharasu ◽  
Z. Hassan ◽  
H. Abu. Hassan
Keyword(s):  
Thin Films ◽  
Surface Topography ◽  
Flow Rate ◽  
Gas Flow ◽  
Process Conditions ◽  
Gas Flow Rate ◽  
Glass Substrates ◽  
Sputtering Power ◽  
Large Particles ◽  
Ar Gas

Al thin films were prepared over different substrates at various process conditions using DC sputtering. The surface topography of all prepared films was examined using AFM technique. Very smooth, uniform and dense surface were observed for Al films coated over Glass substrates. The observed particle size was nano scale (20 -70 nm) for Glass substrates. Sputtering power showed immense effect on surface roughness with respective to Ar gas flow rate. Noticeable change on surface with large particles was observed in Copper substrates at various sputtering power and gas flow rate.

Sign in / Sign up

Export Citation Format

Share Document