Acute rat cutaneous wound healing for small and large wounds using Ar/O ₂ atmospheric-pressure plasma jet treatment

In this study, we developed a rat model of acute wound healing treated by a cold and touchable Ar/O ₂ atmospheric-pressure plasma jet (APPJ) with a jet gas temperature of < 37°C and a length of 15 mm. To generate more abundant reactive oxygen species (ROS) and reactive nitrogen species (RNS), we added various amounts of oxygen into argon. We have found that, with 0.04% oxygen addition, the APPJ can generate the most abundant ROS/ RNS such as hydroxyl radicals (OH*), N ₂ 2 ^nd+ , and O atom in the jet region based on the optical emission spectroscopymeasurements. We then applied the APPJ to treat open wounds of rats directly. To demonstrate the effectiveness of this APPJ treatment for wound healing, we created two wound sizes with diameters of 8 mm (small) and 21 mm (large). The results show that APPJ treatment with 0.04% oxygen addition can greatly accelerate wound healing, especially for the group with large wounds compared with the control group without any treatment. We explain this wound-healing enhancement with plasma jet treatment using a standard histologic method, hematoxylin and eosin staining, from the sectioned skins by comparing the different experimental groups.