Browsing by Author "Wu, Mu-Chien"

Now showing 1 - 3 of 3

A Novel Fabrication of PDMS Chip using Atmospheric Pressure Plasma Jet: Hydrophobicity Modification and Feasibility Test
(2018-01-01)
Yu, Ya-Shen
;
Kuo, Lih-Hwa
;
Wu, Mu-Chien
;
Wu, Jong-Shinn
;
Tsai, Chia-Hung Dylan
This paper presents a new application of atmospheric pressure plasma jet (APPJ) aiming for fabricating a microfluidic system on a polydimethylsiloxane (PDMS) surface. While PDMS is widely used for microfluidic chips, the fabrication of a chip requires different instruments which are not easily accessible for small-scale companies or laboratories. Therefore, we are motivated to develop a simple and low-cost method for such a fluidic system fabrication. The idea of this work is to directly pattern a fluidic channel on a PDMS surface with a plasma jet, which is known for its capability of modifying the hydrophobicity on a surface. The feasibility test first showed that fluid only flows in plasma-treated regions as having physical walls. The plasma parameters were then optimized using Taguchi method based on experiments. The optimization significantly reduce the required plasma treating time from more than 30 treating rounds to only 3 treating rounds, over ten times improved. Methods for further improving the resolution to micrometer-scale have been discussed. In addition to the advantages of fast and low-cost of the proposed method, making microfluidic channels on the surfaces of PDMS chip is also convenient for recollecting cultured cells on a chip in the field of regenerative medicine.
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.
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
;
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.