Local supply of reactive oxygen species into a tissue model by atmospheric-pressure plasma-jet exposure

The supply of reactive oxygen species (ROSs) into a tissue by plasmas must be controlled for the safe and effective use of plasma technologies in biomedical applications. In this study, the two-dimensional distributions of ROSs after passing through an agarose tissue model by the plasma-jet exposures were visualized using a KI-starch gel reagent to evaluate the local ROS supply. Partial ROS supply on the tissue model surface induced the local ROS supply in a pointlike shape just under the plasma-exposed spot. The O-3-containing gas exposure without direct plasma contact could not induce the local ROS supply. Therefore, the local ROS supply was assumed to be induced by plasma-specific effects. However, the results also indicated that the plasma jet coming in direct contact with the tissue model surface did not necessarily induce the local ROS supply. The effects of the tissue model thickness on the local ROS supply were also studied; the local ROS supply could penetrate to a depth of 2mm in the tissue model under the given experimental conditions.