Monitoring of Reactive Oxygen Species Generation with PVA-KI Probe by Argon Plasma*

Atmospheric pressure plasma jet (APPJ) inactivates bacteria and virus through in situ supply of reactive oxygen species (ROSs). These species are strong oxidative stress and/or trigger signaling pathways in biological cells. Polyvinyl Alcohol-Potassium Iodine (PVA-KI) were studied for testing radical productions with long silicone tube and expansion plasma jet. PVA-KI gel also investigated in radiotherapy such as radio chromic gel dosimeter. Visualization of ROSs concentration and distribution is an essential technique for accurate evaluation of absorption dose.

This article describes an PVA-KI has been developed and adapted to the APPJ. The ROSs generation were measured by the color change of PVA-KI gel. When argon plasma jet is used to irradiate PVA-KI gel sample, plasma radical productions are delivered from the gas phase through the liquid phase before reacting with PVA-KI. Not only the distribution patterns of ROS on the expose plasma jet area but also the patterns in the surrounding area were visualized. Currently, color meter device is used for measurement color change of PVA-KI gel corresponding to the absorbed dose of plasma irradiation to PVA-KI gel.

The results also indicated that the plasma jet coming in direct contact with PVA-KI gel sample surface, leading to the color change on the surface sample. Plasma jet did not cause the propagation reaction to inside the PVA-KI gel. Since the radical productions strongly depends on the plasma control parameter, we also investigated the effect of the operating parameters such as irradiation time, distance, applied voltage.