Impact Of Pulse Width Of A Nanosecond Atmospheric Pressure Plasma Jets On The Inactivation Of Pancreatic Cancer Cells In Vitro*

Nanosecond pulsed atmospheric pressure plasma jets (ns-APPJs) produce reactive plasma agents including charged particles, electric field, and reactive oxygen and nitrogen species, which are known to induce oxidative stress, hence suggesting applications in cancer therapy. They can be applied as a stand-alone technology or in combination with pulsed electric fields for synergistic inactivation [1]. The externally applied pulsed power parameters that are used in generating ns-APPJs such as voltage amplitude, pulse duration, and pulse repetition frequency can influence the plasma properties [2] and the resulting biological effects. This study investigates the impact of pulse width on plasma-induced biological effects by evaluating the viability of pancreatic cancer (Pan02) cells. Various pulse durations, ranging from 10 ns to 2.5 µs, were used to drive the plasma, and the charge and energy per pulse delivered to the cell suspension were analyzed by measuring the discharge current and voltage. The intracellular effects of the plasma were examined using flow cytometry and microscopy to elucidate the role of intracellular reactive oxygen species (ROS) in cell death. Additionally, the ROS at the gas-biomaterial interface were characterized using spatiotemporally resolved optical emission spectroscopy.