Effect of direct cold atmospheric plasma (diCAP) on microcirculation of intact skin in a controlled mechanical environment

Objective The microcirculatory response of intact human skin to exposure with direct cold atmospheric plasma (diCAP) for different durations with a focus on the effect of implied mechanical pressure during plasma treatment was investigated. Methods Local relative hemoglobin, blood flow velocity, tissue oxygen saturation and blood flow were monitored non-invasively for up to 1 h in 1-2 mm depth by optical techniques, as well as temperature, pH values and moisture before and after skin stimulation. The experimental protocol (N=10) was set up to differentiate between pressure- and plasma-induced effects. Results Significant increases in microcirculation were only observed after plasma stimulation but not after pressure stimulus alone. For a period of 1 h after stimulation, local relative hemoglobin was increased by 5.1% after 270 s diCAP-treatment. Tissue oxygen saturation increased by up to 9.4%, whereas blood flow was doubled (+106%). Skin pH decreased by 0.3 after 180 s and 270 s diCAP-treatment, whereas skin temperature and moisture were not affected. Conclusion diCAP-treatment of intact skin notably enhances microcirculation for a therapeutically relevant period. This effect is specific to the plasma treatment and not an effect of the applied pressure. Prolonged treatment durations lead to more pronounced effects. This article is protected by copyright. All rights reserved.