Characteristics of Plasma Activated Medium Produced by Atmospheric Pressure Helium Plasma Jet and Its Selective Effect on Malignant Melanoma and Normal Fibroblast Cells

The characteristics of plasma activated medium (PAM) and its different effects on cancer and normal cells are a relevant topic of study in the field of plasma medicine. In this study, an atmospheric pressure plasma jet (APPJ) with helium was applied for generating PAM, which was utilized for malignant melanoma (B16) and normal fibroblast (3T3) cell treatment. With the applied peak-peak voltages of 8, 10, and 12 kV, together with the gas flow rates of 1, 2, and 3 L/min, the characteristics of He APPJ and PAM were investigated, respectively. The results showed that compared with the free-standing jet, both the total power that was dissipated into the APPJ device and the emission intensities of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the gas phase increased when it interacted with the medium. There were obvious increases of H₂O₂ and NO₂^- in PAM with different APPJ activation time of 5, 10, 15, 30, 45, and 60 s. The gas flow rate did not yield significant differences in the concentration of species generated, the applied voltage being a more relevant parameter. Finally, the results of cell viability and cell apoptosis assay indicated that the identical dose PAM had a selective effect on two kinds of nonhomologous cells.