Repeated cold atmospheric plasma application to intact skin does not cause sensitization in a standardized murine model

Abstract

Cold atmospheric plasma (CAP) is a promising option for the treatment of chronic wounds and superficial cancer. Recent studies show that CAP has excellent microbicidal and antibiofilm activity, stimulates angiogenesis and cell proliferation, and induces apop-tosis in cancer cells. The kINPen MED transportable plasma jet is a certified medical device that needs to be tested for irritant and allergenic side effects. We used a murine local lymph node assay (according to the Organisation for Economic Co-operation and Development protocol) to evaluate the kINPen MED’s potential to trigger skin sensitization. Our results showed that 25 s of CAP exposure did not induce skin sensitization compared with the vehicle control (acetone/olive oil mixture). The CAP-treated group had a stimulation index (SI) of 0.76, which was significantly lower than the > 1.8 threshold (SI = 0.46 for the vehicle control group). Pure argon gas flow also did not induce sensitization. Moreover, we did not observe any serious effects on proliferation activity in local lymph nodes (assessed via visual analysis, adenosine triphosphate content, and histology). This study confirmed that the use of the kINPen MED device did not cause any harmful sensitization or irritation in a murine model.