Cold Plasma Jet Experiment Report

2. Experiment
2.1. Cold Plasma Jet System
This research used a cold atmospheric pressure plasma jet system with an inclined style of treatment (gradient = 45o) as shown in Figure 1. This system was developed based on Teschke et al.32 Medical-grade argon gas (99.999% purity) produced by the Samator Company (Indonesia) was used as a carrier gas. Two aluminium foil ring electrodes were used around the quartz tube for this system. It had a quartz tube with a 1.5 mm inner diameter and a 2.7 mm outer diameter. The quartz tube was produced by the Fujiwara Company (Japan). The distance between the 2 electrodes was 17 mm. The lower ring electrode was connected to the ground. A low-frequency (~20 kHz) AC high voltage, with a peak-to-peak voltage of
Ltd., Gifu, Japan) following a described technique.20 Considering the evaluation results of H2O2 concentrations as shown in Figures 6 and 7, a plasma jet with an inclined style of treatment was conducted once daily for 2 minutes over 14 days. The position of the wound surface was about 15 mm from the nozzle tip with a defined slope (45o in gradient) as shown in Figure 1. In the plasma-treated group (P), the tip of the plasma jet touched the wound surface. The daily room temperature and room humidity during the 14 days of the experiment represented a tropical room condition as detailed in Figure
Macroscopic Evaluation of Wound
The day when the wounds were created was designated as day 0, and the process of wound healing was observed daily from day 0 to day 14. Before observation, the environment surrounding the wounds was cleaned with saline solution. Wound edges were traced on polypropylene sheets and photographs were taken every day. The traces on the sheets were captured with a scanner onto a personal computer using Adobe Photoshop Elements 7.0 and the areas of the wounds were calculated using the image analysis software Scion Image Beta 4.02 (Scion Corporation, Frederick, Maryland, USA).

2.11. Prediction of Healing Day
The day of wound healing was predicted based on visual inspection of the wounds using a graph of the ratio of the wound area to the wound’s initial area. Initially, the overall trend of this graph was evaluated. The healing day was plotted on the y-axis when the trend of reduction of the wound size started to become flat, as reported previously,20, 21 which was at 0.33 (see Figure 8a). From that plotted point, line z was made, crossing the lines of reduction for each group. Wound healing days at points P*, PMWD*, PMWDH*, and C* were then made based on the lines from their meeting points to the