Influence of non-thermal atmospheric pressure plasma on cellular structures and processes in human keratinocytes (HaCaT)

BackgroundThe use of non-thermal atmospheric pressure plasma in dermatology to improve the healing of chronic wounds is a promising application. The antimicrobial properties of physical plasma offer on the one hand the killing of bacteria, which are often a problem in chronic wounds. On the other hand, plasma can activate cells which are involved in the wound closure.ObjectiveTo guarantee a safe application it is essential to understand basic interactions between physical plasma and human skin cells.MethodsIn our study, human keratinocytes (HaCaT cells) were directly plasma treated with a dielectric barrier discharge (DBD) plasma source and effects on viability, DNA, cell cycle, intracellular concentration of reactive oxygen species and induction of apoptosis were observed.ResultsA treatment time-dependent loss of recovered adherent HaCaT cells after 24 h and a linear increase of DNA damage were observed, which was no longer evident 24 h after plasma stimulation, except for long treatment times. An accumulation of HaCaT cells in G2/M phase and a decrease in the G1 phase was caused by DBD plasma. The increasing formation of intracellular ROS is also attributed to plasma treatment. In contrast to other studies we did not find clear evidences for apoptosis in adherent HaCaT cells. A culture medium exchange subsequently after plasma treatment weakened the observed effects.ConclusionDBD plasma treatment resulted in oxidative stress in human keratinocytes which is related to deficient cell performance.