Browsing by Author "Liu, Chih-Tung"

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A Cold Planar Nitrogen-Based Atmospheric-Pressure Dielectric Barrier Discharge Jet With Enhanced UV Emission and Radical Generation Using Short Electrodes
(2016-12)
Cheng, Kuang-Yao
;
Yang, Yi-Wei
;
Lin, Zhi-Hua
;
Liao, Guo-Chun
;
Liu, Chih-Tung
In this paper, a planar nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet with enhanced UV emission and radical generation, and much lower power consumption and gas temperature using shorter electrodes as compared with a previously developed DBD jet is presented. The highest UV intensity (five times larger) and radical generation (two times larger) in the DBD jet region are found to occur when the electrode length is 1 cm. Corresponding jet gas temperature and power consumption are 31 degrees C and 39 W, respectively. The 1-cm DBD jet was used to treat polylactide film for enhancing its hydrophilic properties. The results show that a contact angle of 28.4 degrees could be obtained with a residence time of 4 s. The resulting 1-cm DBD jet may provide an efficient surface treatment tool for delicate industrial and biomedical devices/materials.
A Cold Planar Nitrogen-Based Atmospheric-Pressure Dielectric Barrier Discharge Jet With Enhanced UV Emission and Radical Generation Using Short Electrodes
(2016-12-01)
Cheng, Kuang-Yao
;
Yang, Yi-Wei
;
Lin, Zhi-Hua
;
Liao, Guo-Chun
;
Liu, Chih-Tung
In this paper, a planar nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet with enhanced UV emission and radical generation, and much lower power consumption and gas temperature using shorter electrodes as compared with a previously developed DBD jet is presented. The highest UV intensity (five times larger) and radical generation (two times larger) in the DBD jet region are found to occur when the electrode length is 1 cm. Corresponding jet gas temperature and power consumption are 31 degrees C and 39 W, respectively. The 1-cm DBD jet was used to treat polylactide film for enhancing its hydrophilic properties. The results show that a contact angle of 28.4 degrees could be obtained with a residence time of 4 s. The resulting 1-cm DBD jet may provide an efficient surface treatment tool for delicate industrial and biomedical devices/materials.
An Optimized Two-Step Nitrogen-Based Plasma Treatment Procedure under Atmospheric-Pressure Condition and its Surface Amination Mechanism
(2015-07-01)
Yang, Yi-Wei
;
Wu, Jane-Yii
;
Liu, Chih-Tung
;
Liao, Guo-Chun
;
Cheng, Kuang-Yao
Atmospheric pressure nitrogen-based dielectric barrier discharge (DBD) jet with two-step plasma treatment procedure has been verified to be very effective in facilitating nitrogen-containing group incorporation on Polylactide (PLA) surface. It includes: 1) pretreatment plasma treatment by a nitrogen discharge with a trace amount of oxygen, and 2) ammonia plasma treatment by a nitrogen discharge with a small amount of ammonia. In this study, the optimized operation condition of two-step plasma procedure is investigated under different concentrations of added gases (0-1% oxygen; 0-10% ammonia). XPS analysis shows that approximate to 0.19 of N/C ratio can be achieved by means of the optimized two-step plasma procedures. Furthermore, a surface amination mechanism is proposed based on the observations of Optical Emission Spectra (OES), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectra (XPS) analyses.
Analysis of Hydroxyl Radical and Hydrogen Peroxide Generated in Helium-Based Atmospheric-Pressure Plasma Jet and in Different Solutions Treated by Plasma for Bioapplications
(2020-06-22)
Chen, Tsung-Wen
;
Liu, Chih-Tung
;
Chen, Chao-Yu
;
Wu, Mu-Chien
;
Chien, Po-Chien
This study systematically analyzed reactive species generated with self-built helium-based low-temperature atmospheric-pressure plasma jet (He-APPJ); we measured the hydroxyl radical (OH) and hydrogen peroxide (H2O2) above surfaces of plasma-treating solutions and in plasma-treated medium (PTM) of different solutions, including deionized water, phosphate buffered saline, and Dulbecco's modified Eagle medium. The effects of adding O(2)into He working gas on OH and H(2)O(2)generation were discussed. The MCF7 cell responses to plasma treatment were also observed. The OH emission (309 nm) in He-APPJ and above surfaces of plasma-treating solutions were analyzed through optical emission spectroscopy, and concentrations of OH and H(2)O(2)in different solutions were measured using terephthalic acid and Amplex Red, respectively. In our plasma system, it was observed that higher conductivity of solutions may cause stronger OH emission above solution. The ingredients of the solution may affect the concentrations of OH and H2O2. Addition of 0.1% O(2)generates strongest OH emission above surfaces of plasma-treating solution with our He-APPJ, and thus, the highest H(2)O(2)concentration in PTM. The MCF7 cell viability is influenced by the H(2)O(2)concentration in PTM. The results of this study can facilitate further study of plasma effects on PTM and cell culture.
Atomic Oxygen and Hydroxyl Radical Generation in Round Helium-Based Atmospheric-Pressure Plasma Jets by Various Electrode Arrangements and Its Application in Sterilizing Streptococcus mutans
(2014-12-01)
Liu, Chih-Tung
;
Wu, Ching-Jung
;
Yang, Yi-Wei
;
Lin, Zhi-Hua
;
Wu, Jong-Shinn
The reactive chemical species generated in an atmospheric-pressure plasma jet (APPJ), such as hydroxyl radical and atomic oxygen, are generally regarded as the major sources for several biomedical applications. In this paper, we propose an APPJ with a 25-kHz high-voltage powered stainless steel tube fixed inside a quartz tube and an aluminum grounded electrode that is wrapped around the quartz tube. The results show that the radical intensities of atomic oxygen and hydroxyl radical, gas temperature, and power absorption increase with increasing distance of discharge gap distance under the same applied voltage. Increasing the width of grounded electrode increases gas temperature and causes higher power absorption but only slight change of radical generation. We have applied the APPJ with the conditions of highest radical generation (grounded electrode width = discharge gap distance = 15 mm) for effectively sterilizing Streptococcus mutans within 15 s, which shows a highly potential application for root canal disinfection.
DEVELOPMENT AND CHARACTERIZATION OF A PORTABLE ATMOSPHERIC-PRESSURE ARGON PLASMA JET FOR STERILIZATION
(2016)
Lin, Zhi-Hua
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Wu, Jong-Shinn
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Tschang, Chen-Yon Tobias
;
Su, Chi-Feng
;
Wu, Tuoh
In this study, we would like to develop a portable round argon atmospheric-pressure plasma jet (APPJ) which can be applied for general use of bacteria inactivation. The APPJ was characterized electrically and optically, which include measurements of absorption power, gas temperature and optical properties of plasma generated species. Measured OH* number density at 5 mm downstream was estimated to be 5.8 x 10(15) cm(3) and the electron density and electron temperature were estimated to be 2.4 x 10(15) cm(-3) and 0.34 eV, respectively, in the discharge region. This APPJ was demonstrated to effectively inactivate E. coli within seconds of treatment, which shows its great potential in the future use of general bacteria inactivation and sterilization.
Effect of Ground and Floating Electrode on a Helium-Based Plasma Jet and Its Applications in Sterilization and Ceramic Surface Treatment
(2016-12)
Liu, Chih-Tung
;
Cheng, Kuang-Yao
;
Lin, Zhi-Hua
;
Wu, Ching-Jung
;
Wu, Jane-Yii
In this paper, we compare the helium-based atmospheric pressure plasma jets (APPJs) with power-ground (PG) and power-floating (PF) configurations by using optical analysis. We find that the PG jet traps plasma between two electrodes (discharge region); thus, the hydroxyl radical intensity is significantly strong in discharge region; however, the plasma intensity in downstream region is relatively weak as compared with that of PF configuration. In contrast, using the APPJ with PF configuration, the hydroxyl radical and nitric oxide are approximately two and three times stronger, respectively, in the downstream region, even though the gas temperature and power consumption are lower. The PF jet successfully eradicates S. mutans and decreases water contact angle by similar to 40 within 15-s treatment, which demonstrates higher efficient than that of PG jet, and shows highly potential for dental filling demand.
Effect of Ground and Floating Electrode on a Helium-Based Plasma Jet and Its Applications in Sterilization and Ceramic Surface Treatment
(2016-12-01)
Liu, Chih-Tung
;
Cheng, Kuang-Yao
;
Lin, Zhi-Hua
;
Wu, Ching-Jung
;
Wu, Jane-Yii
In this paper, we compare the helium-based atmospheric pressure plasma jets (APPJs) with power-ground (PG) and power-floating (PF) configurations by using optical analysis. We find that the PG jet traps plasma between two electrodes (discharge region); thus, the hydroxyl radical intensity is significantly strong in discharge region; however, the plasma intensity in downstream region is relatively weak as compared with that of PF configuration. In contrast, using the APPJ with PF configuration, the hydroxyl radical and nitric oxide are approximately two and three times stronger, respectively, in the downstream region, even though the gas temperature and power consumption are lower. The PF jet successfully eradicates S. mutans and decreases water contact angle by similar to 40 within 15-s treatment, which demonstrates higher efficient than that of PG jet, and shows highly potential for dental filling demand.
Effects of assisted magnetic field to an atmospheric-pressure plasma jet on radical generation at the plasma-surface interface and bactericidal function
(2016-12)
Liu, Chih-Tung
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Kumakura, Takumi
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Ishikawa, Kenji
;
Hashizume, Hiroshi
;
Takeda, Keigo
A configuration of magnetic-assisted-plasma (MAP) on helium-based atmospheric-pressure plasma jet (APPJ) with an axial magnetic-field of 0.587 T is proposed, which provides good ability for killing bacteria Escherichia coli on the agar surface. Optically, we confirmed that the MAP increased approximately 2.4 times in the electron density estimated by the Stark broadening of H-beta line emission, and approximately 1.5 times enhancement of atomic oxygen concentration measured by vacuum ultraviolet absorption spectroscopy (VUVAS). Moreover, the generation of hydroxyl radical in the water increased 1.5 times, confirmed by the spin-trapping electron spin-resonance technique. In addition, the bactericidal experiments demonstrated 2.4 times higher for E. coli by the MAP treatment. The MAP configuration is proposed to be highly useful for future bio-medical applications by enhancing the radical generation at the plasma/substrate interface region.
Enhancement of cell growth on honeycomb-structured polylactide surface using atmospheric-pressure plasma jet modification
(2017-02-01)
Cheng, Kuang-Yao
;
Chang, Chia-Hsing
;
Yang, Yi-Wei
;
Liao, Guo-Chun
;
Liu, Chih-Tung
In this paper, we compare the cell growth results of NIH-3T3 and Neuro-2A cells over 72 h on flat and honeycomb structured PLA films without and with a two-step atmospheric-pressure nitrogen-based plasma jet treatment. We developed a fabrication system used for forming of a uniform honeycomb structure on PLA surface, which can produce two different pore sizes, 3-4 mu m and 7-8 mu m, of honeycomb pattern. We applied a previously developed nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet system to treat the PLA film without and with honeycomb structure. NIH-3T3 and a much smaller Neuro-2A cells were cultivated on the films under various surface conditions. The results show that the two-step plasma treatment in combination with a honeycomb structure can enhance cell growth on PLA film, should the cell size be not too smaller than the pore size of honeycomb structure, e.g., NIH-3T3. Otherwise, cell growth would be better on flat PLA film, e.g., Neuro-2A. (C) 2016 Elsevier B.V. All rights reserved.
Fast incorporation of primary amine group into polylactide surface for improving C2C12 cell proliferation using nitrogen-based atmospheric-pressure plasma jets
(2014-01-01)
Yang, Yi-Wei
;
Wu, Jane-Yii
;
Liu, Chih-Tung
;
Liao, Guo-Chun
;
Huang, Hsuan-Yu
In this article, we report the development of the fast incorporation of primary amine functional groups into a polylactide (PLA) surface using the post-discharge jet region of an atmospheric-pressure nitrogen-based dielectric barrier discharge (DBD). Plasma treatments were carried out in two sequential steps: (1) nitrogen with 0.1% oxygen addition, and (2) nitrogen with 5% ammonia addition. The analyses show that the concentration of N/C ratio, surface energy, contact angle, and surface roughness of the treated PLA surface can reach 19.1%, 70.5 mJ/m(2), 38 degrees and 73.22 nm, respectively. In addition, the proposed two-step plasma treatment procedure can produce a PLA surface exhibiting almost the same C2C12 cell attachment and proliferation performance as that of the conventional gelatin coating method. Most importantly, the processing/preparation time is reduced from 13-15 h (gelatin coating method) to 5-15 min (two-step plasma treatment), which is very useful in practical applications. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 160-169, 2014.
Inactivation Effect of Colletotrichum Gloeosporioides by Long-Lived Chemical Species Using Atmospheric-Pressure Corona Plasma-Activated Water
(2019-02-01)
Wu, Mu-Chien
;
Liu, Chih-Tung
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Chiang, Chun-Yi
;
Lin, Yi-Jia
;
Lin, Ying-Hong
In this paper, atmospheric-pressure air and oxygen corona plasma jets under water surface have been used to generate plasma-activated water (PAW) to inactivate colletotrichum gloeosporioides (C. gloeosporioides) suspension. The atmospheric-pressure plasma jets in the water were characterized by measuring: 1) the electrical and optical properties for evaluating the plasma efficiency and 2) the physicochemical properties of PAW, including pH value, oxidation-reduction potential value, and the concentration of hydrogen peroxide, nitrite, and ozone. The aim of this paper is to investigate the effects of long-lived reactive oxygen and nitrogen species (RONS) and environmental factor (acidity) in PAW on fungicidal property. The results of antifungal activity show that the inactivation rate of C. gloeosporioides is higher using air-PAW than oxygen-PAW, and increases with increasing reaction time when preparation time of PAW is fixed as 30 min. This correlates well with measurements of the aqueous-phase long-lived RONS concentration such as nitrate and ozone, suggesting these species play crucial roles in the inactivation process.
Production Enhancement of Reactive Oxygen and Nitrogen Species at Interface of Helium Plasma Jet and Agar
(2016-12)
Liu, Chih-Tung
;
Wu, Ching-Jung
;
Lin, Zhi-Hua
;
Wu, Jane-Yii
;
Wu, Jong-Shinn
Even though atmospheric-pressure plasma jet (APPJ) has been shown highly effective in many biomedical applications because of reactive oxygen/nitrogen species (RONS) generated in the discharge, free jet region, and at the interfacial region with the treated surface. However, most of the studies characterized APPJ only in either discharge or free jet region. In this paper, we measured optical emissions of RONS in free jet and plasma/surface interfacial regions of a helium-based dielectric barrier discharge APPJ. The results show that the emissions caused by RONS (nitric oxide, hydroxyl radical, and atomic oxygen) are enhanced 3-5 times at plasma/surface interfacial region as compared with those of free jet region. Some typical sterilization experiments using the current helium-based APPJ show that this helium-based APPJ effectively kills the oral bacteria (S. mutans) in 15 s, which was caused by the cell wall disruption. We believe that measuring the properties at plasma/surface interfacial region is more important than in the free jet region in characterizing APPJ for most realistic applications.
Production Enhancement of Reactive Oxygen and Nitrogen Species at Interface of Helium Plasma Jet and Agar
(2016-12-01)
Liu, Chih-Tung
;
Wu, Ching-Jung
;
Lin, Zhi-Hua
;
Wu, Jane-Yii
;
Wu, Jong-Shinn
Even though atmospheric-pressure plasma jet (APPJ) has been shown highly effective in many biomedical applications because of reactive oxygen/nitrogen species (RONS) generated in the discharge, free jet region, and at the interfacial region with the treated surface. However, most of the studies characterized APPJ only in either discharge or free jet region. In this paper, we measured optical emissions of RONS in free jet and plasma/surface interfacial regions of a helium-based dielectric barrier discharge APPJ. The results show that the emissions caused by RONS (nitric oxide, hydroxyl radical, and atomic oxygen) are enhanced 3-5 times at plasma/surface interfacial region as compared with those of free jet region. Some typical sterilization experiments using the current helium-based APPJ show that this helium-based APPJ effectively kills the oral bacteria (S. mutans) in 15 s, which was caused by the cell wall disruption. We believe that measuring the properties at plasma/surface interfacial region is more important than in the free jet region in characterizing APPJ for most realistic applications.
Tooth bleaching by using a helium-based low-temperature atmospheric pressure plasma jet with saline solution
(2017-11-01)
Cheng, Yun-Chien
;
Wu, Chia-Hua
;
Liu, Chih-Tung
;
Lin, Chia-Yung
;
Chiang, Hsuan-Ping
In this study, tooth bleaching was performed by using a helium-based low temperature atmospheric-pressure plasma jet (He-APPJ) with saline solution to avoid ozone and hydrogen peroxide (H2O2) harm. In this study, tooth samples were treated through three approaches, namely a helium flow with saline, H2O2 gel, and He-APPJ with saline. The bleaching efficacy of the He-APPJ treatment was the highest among the three groups. Furthermore, scanning electron microscopy images showed that enamel treated with He-APPJ was much less damaged than that treated with H2O2 gel. In addition, ozone tests showed that APPJ produced little ozone (<0.35ppm). In conclusion, He-APPJ with saline solution achieves higher bleaching efficacy and is less harmful than methods that use H2O2 gel.