Influence of non-thermal plasma on human cell activities

In physics, plasma is known as the fourth state of matter and describes a partially or fully ionized gas. Recently, non-thermal atmospheric pressure plasma sources gained attention as a possible tool for biomedical applications, emitting UV radiation and generating reactive oxygen and nitrogen species (ROS, RNS). It is well known that prokaryotes die during a plasma treatment whereas eukaryotes are able to survive a comparable treatment. Therefore plasma is very interesting for healing chronic wounds. The aim of this work is to analyze plasma-mediated activation of human cells of different origin (skin, connective tissue and immune system). Therefore human keratinocytes (HaCaT), fibroblasts (MRC5) and immune cells (Jurkat T-cells and THP1 monocytes) were investigated by numerous genomic and proteomic approaches, applying a modified version of the kINPen09 plasma source. Applying a 84 genes wound healing panel the up or down regulation of different genes (ECM and adhesion, growth factors and signaling molecules, inflammatory cytokines and chemokines,) after plasma treatment could be detected. Employing HPLC-MS techniques, we were able to identify more than 3300 human proteins, which were partially confirmed by western blotting and 2D gel electrophoresis. Proteins detected cover a wide range of molecular functions (e.g. antioxidant activities) and a broad spectrum of biological processes (e.g. regulation of cell cycle; cell signaling). Investigating the cellular responses to non-thermal plasma treatment, we were able to identify several cell specific genes and proteins, which were activated after plasma treatment. Especially cell signaling and pro-proliferative signal molecules were activated after short term plasma treatment indicating stimulatory effects of non-thermal plasmas. However, while all types of cells showed a comparable pattern of activated molecules after plasma treatment, there are some differences in the cellular reactions, displaying diverse sensitiv- ties of the investigated cells towards nonthermal plasma treatment.