Induction of proliferation of basal epidermal keratinocytes by cold atmospheric‐pressure plasma

Summary Background Over the past few decades, new cold plasma sources have been developed that have the great advantage of operating at atmospheric pressure and at temperatures tolerable by biological material. New applications for these have emerged, especially in the field of dermatology. Recently it was demonstrated that cold atmospheric‐pressure plasma positively influences healing of chronic wounds. The potential of cold plasma lies in its capacity to reduce bacterial load in the wound while at the same time stimulating skin cells and therefore promoting wound closure. In recent years, there have been great advances in the understanding of the molecular mechanisms triggered by cold plasma involving signalling pathways and gene regulation in cell culture. Aim To investigate cold plasma‐induced effects in ex vivo treated human skin biopsies. Methods Human skin tissue was exposed to cold plasma for different lengths of time, and analysed by immunofluorescence with respect to DNA damage, apoptosis, proliferation and differentiation markers. Results After cold plasma treatment, the epidermal integrity and keratin expression pattern remained unchanged. As expected, the results revealed an increase in apoptotic cells after 3 and 5 min of treatment. Strikingly, an induction of proliferating basal keratinocytes was detected after cold plasma exposure for 1 and 3 min. As these are the cells that regenerate the epidermis, this could indeed be beneficial for wound closure. Conclusion We investigated the effect of cold plasma on human skin by detecting molecules for growth and apoptosis, and found that both processes are dependent on treatment time. Therefore, this approach offers promising results for further applications of cold plasma in clinical dermatology.