Selectivity of Non-Thermal Atmospheric- Pressure Microsecond-Pulsed Dielectric Barrier Discharge Plasma Induced Apoptosis in Tumor Cells over Healthy Cells

Non-thermal plasma is now being widely investigated for various clinical ap- plications ranging from surface sterilization to blood coagulation to wound healing to cancer therapy. We have shown previously that reactive oxygen species (ROS) generated by non- thermal dielectric barrier discharge (DBD) plasma in the medium surrounding the cells induce DNA damage in mammalian cells, and by tuning the dose, plasma has various effects, from enhancing proliferation to inducing apoptosis in cancer cells. 1-3 Although non-thermal plasma primarily produces ROS extracellularly, we hypothesize that it can induce apoptosis in ma- lignant cells similar to ionizing radiation or photodynamic therapy, which primarily produce ROS intracellularly. Unlike ionizing radiation, which damages healthy tissue surrounding the malignant tissue, 4,5 or photodynamic therapy, which causes scarring and burning of nearby healthy tissue, non-thermal plasma, due to its non-penetrating nature, may provide a safer means to induce selective apoptosis in malignant tissue by providing precise control of treat- ment area and depth.