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 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 noninvasively for up to 1 hour 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 seconds 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 seconds and 270 seconds diCAP treatment, whereas skin temperature and moisture were not affected. CONCLUSIONS: 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.