On the path for controlled ROS modulation based on nanosecond pulsed plasmas*

Nanosecond pulsed atmospheric pressure plasma jets (ns-APPJs) efficiently produce reactive plasma species, including charged particles and reactive oxygen and nitrogen species (RONS), with the gas temperature near the room temperature, and are hence known to be a promising strategy for various biomedical applications including cancer therapy, gene delivery and heat-sensitive surface sterilization. Our recent studies have shown that RONS production, depending on the properties of the biological target that the plasma is impinging on[1], can be modulated with plasma treatment time, pulse voltage, duration, and repetition frequency[2]. Nanosecond pulsed electric field (nsPEF) with sufficient intensity also causes permeabilization of cell membranes and induce apoptosis or cell death. Combining ns-APPJ with nsPEF treatments enhances the effectiveness of cancer cell inactivation by exerting only moderate doses of both treatments[3]. This talk reviews the dependence of OH and H₂O₂ generation, and electric field distribution in a liquid-impinging ns-APPJ on the target properties (e.g., liquid conductivity) and the pulse parameters (e.g., pulse duration, repetition frequency). The regulated ROS response using the ns-APPJ for a pancreatic cancer cell (Pan02) inactivation and the synergistic effects from the combined ns-APPJ and nsPEF treatments with both a viability assay and transcellular electrical resistance (TER) measurements are also discussed.