An Analysis of Nanosecond Pulsed Streamer Discharges in Treating Melanoma Cancer Cells: Generation, Source-Plasma Interaction, and Energy Efficiency

Samira Elaissi^*Norah A M AlsaifEman M MoneerSoumaya Gouadria

• Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Atmospheric pressure plasma has great potential in medicine, such as cancer therapy and wound treating. The skin cancer therapy is challenging due to the thin layer of biological liquid that generally covers the sample. This study aims to perform a numerical simulation of nanosecond high-voltage pulses plasma streamers applied to human tissue for melanoma cancer cells therapy. This study investigates the optimization of plasma energy transfer in relation to several parameters, such as voltage, total energy, pulse frequency, flow rate, input power, and pressure. Results show that transient electric discharges can reach much higher levels of electron energy than static discharges. As voltage increases, most reactive species' densities increase, and streamer length rises due to higher power deposition. Also, as the pressure varies from one atmosphere to 0.3 MPas, the breakdown time increases and the propagation velocity of the ionizing front decreases. Pulse frequency affects thermal processes since contact time and input power of plasma increase with frequency. Due to a gradual cascade of biochemical processes that occur after treatment, melanoma cells often undergo apoptosis resulting in slow cell death rather than necrosis that occurs immediately. Melanoma cell death is most likely caused by the hydroxyl radical OH species produced from water vapor which damages the outer surface of cancer cell through oxidation process. Reactive oxygen and nitrogen species (RONS) like NO and O arising as either primary products or metabolic byproducts have less influence. Based on these findings it appears that these results are extremely important for treating cancer cells with nonthermal streamer discharge plasma.