The investigation of solid and hollow electrode APPJs in discharge characteristics and anticancer effects

Cold atmospheric pressure plasmas (CAPs) have a promising application in cancer treatment, the needle-ring electrodes plasma jet is one of the common CAPs sources. Here, we compared the discharge characteristics and anticancer effects in two plasma jets: solid electrode and hollow electrode with six working gases (He, He + 0.5%O₂, He + 0.5%N₂, Ar, Ar + 0.5%O₂, and Ar + 0.5%N₂). The results show the solid plasma jet is slightly stronger according to discharge image, optical emission spectroscopy, and concentration of H₂O₂ and NO₂⁻. We used the leukemia cell THP-1 as the model to detect the anticancer effect, cell viability assay demonstrated a solid electrode plasma jet with He + 0.5%N₂ has less cell survival. Moreover, apoptosis increased significantly as the plasma treatment time and Cleaved-PARP1 upregulated, SOD1 and p21 downregulated in a time-dependent manner. Our work suggested that a solid electrode plasma jet with He + 0.5%N₂ may be a novel therapeutic method for acute myeloid leukemia.