Excitation Frequency-Controlled Cold Atmospheric Pressure Plasma: Effects of N₂ Admixture on Ar Discharge Properties and Breast Cancer Cell Death

A newly developed excitation frequency-controlled cold atmospheric pressure plasma (EFCAP) jet produces a variable density of reactive oxygen and nitrogen species (RONS) by merely modifying the excitation frequency. The composition of reactive species and gas temperature can both be controlled by changing the plasma gas composition because different applications may require distinct plasma properties. This study examines the impact of nitrogen addition on the electrical parameters and emission characteristics of argon plasma generated at 15 kHz. The study was conducted using a mixture of Ar (as the working gas) and N2 (5%, 10%, and 20%). The discharge voltage and current are observed to increase with N2, which causes a significant decrease in the intensity of the Ar emission. The breast cancer cell (MCF-7) death is consistent with the emission data and indicates that cells treated with Ar–N2 plasma have higher survival rates than cells treated with Ar plasma alone. This study provides more insight into the need for careful addition of N2 to argon in the current EFCAP configuration for any specific application.