Cold Atmospheric Pressure Plasma-Activated Liquids for Cancer Treatment

Low-temperature plasma (LTP) is a promising tool that can assist in cancer treatment. Plasma-treated liquids have shown a selective cytotoxic effect on cancer cells attributed to reactive species formed in discharge, but this mechanism is not completely understood. In this study, the chemical compounds formed by plasma irradiation of Ringer’s lactate solutions and their effects on non-tumorigenic breast epithelial cells (MCF-10A) and breast cancer cells (MCF-7) were investigated. Among these compounds, glyceric acid increased the cell viability by more than two-fold compared to the control samples for MCF-10A and MCF-7 cells, whereas the tricarballylic acid had a pronounced cytotoxic effect on the cells when incubated with solutions of 0.6 mM to 50 mM concentrations. A good selectivity in killing the cancer cells was observed when the chemical compounds identified in plasma-treated liquids (such as ethyl acetate, glyceric acid, and tricarballylic acid) were used in a mixture solution of a certain concentration. The results show that the LTP-generated chemical compounds have both, stimulatory and inhibitory effects on cell viability, and the best selectivity is achieved only when these compounds are combined in a certain amount and have a synergistic effect, completely killing only the cancer cells.