AVS 62nd International Symposium & Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS-ThP

Paper PS-ThP13
Two Dimentional Visualization of Oxidation Effect of Scalable DBD Plasma Irradiation using KI-starch Solution

Thursday, October 22, 2015, 6:00 pm, Room Hall 3

Session: Plasma Science and Technology Poster Session
Presenter: Thapanut Sarinont, Kyushu University, Japan
Authors: K. Koga, Kyushu University, Japan
T. Amano, Kyushu University, Japan
T. Sarinont, Kyushu University, Japan
T. Kawasaki, Nippon Bunri University, Japan
G. Uchida, Osaka University, Japan
H. Seo, Kyushu University, Japan
N. Itagaki, Kyushu University, Japan
M. Shiratani, Kyushu University, Japan
Y. Nakatsu, Kyushu University, Japan
A. Tanaka, Kyushu University, Japan
Correspondent: Click to Email
Biomedical applications of plasmas have been extensively explored by applying various plasma sources such as corona discharges, dielectric barrier discharges (DBD), gliding arc, and spark discharges. Quantitative evaluation of oxidation effect of these plasma sources is crucial to select one of the sources appropriate to an application, because most applications employ the oxidation effect. Here we have assessed the oxidation effect of our scalable DBD plasmas using KI-starch solution, the color of which changes from transparent to purple by the oxidation of I- to I2 [1]. Experiments were conducted using the scalable DBD device of 40x44 mm2 in discharge area [2, 3]. 360 μl of solution of 0.5 % potassium iodide and 0.5 % starch was put in each well of a 96 well plate. The well plate was set at 3-10 mm below the electrode and then the solution was irradiated by the discharge plasma. The discharge voltage and current were 9.2 kV and 0.2 A. The discharge duration was 15 s. After the plasma irradiation absorbance at 560 nm of the solution in each well was measured with a plate reader (BioTeK Synergy HT). Two dimensional spatial profiles (71x54 mm2 in area) of the oxidation effect was obtained by one plasma irradiation experiment. At y= 3 mm below the electrodes the absorbance is nearly constant of 2.6 O.D. under the electrode area, while it sharply decreases to 0.1 O.D. at x= 9 mm outside from the electrode edge x= 0 mm. At y= 10 mm, the absorbance is 2.6 O.D. at the center of the electrodes and gradually decreases even under the electrode area with increasing the distance from the center. It becomes 0.04 O.D. at x= 9 mm. Nonthermal air plasma provides ROS, RNS, charged species and photons to the well plate. Among these species, ROS and charged species are important oxidation species based on the experimental results.

This work was partly supported by KAKENHI Grant Numbers 24108009 and 24340143.

[1] T. Kawasaki, et al., IEEE Trans. Plasma Sci. 42, 2482 (2014).

[2] T. Sarinont, et al., JPS Conf. Proc. 1, 015078 (2014).

[3] S. Kitazaki, et al., Curr. Appl. Phys., 14, S149 (2014).