Spark Piezotransformer-Based Discharge in Argon Flow for Stimulating Plasma-Induced Cell Death of the Human Cancer Cells HEp-2

One of the promising methods for generating low-temperature plasma to address oncological issues is a spark discharge initiated by a piezotransformer. This is attributed to its relative simplicity and versatility in application, both in the direct treatment of biological objects in vitro and in vivo, as well as indirectly through the production of plasma-activated solutions. The study presents the results of a comprehensive study of the effect of spark discharge initiated by a piezotransformer in argon flow on the metabolic activity and survival rate of cancer HEp-2 cells. For this purpose, adhesive cells cultured in DMEM were subjected to plasma exposure of different duration (from 10 to 120 s). The produced effect was assessed by studying the spark discharge optical emission spectra, as well as by measuring the concentrations of reactive oxygen and nitrogen species in the liquid medium. Cell viability and metabolic rate were determined by MTT test and fluorescence microscopy using propidium iodide (PI) and Hoechst dyes. The metabolic activity of cells is reduced by half after 20 s of treatment, cell viability reduced after 150 s of treatment. The concentration of hydrogen peroxide H2O2 reaches a value of ~50 μM, and the concentration of nitrite ion NO2- reaches a value of ~20 μM.