The feasibility study of plasma-activated water as physical therapy to induce apoptosis in melanoma cancer cells in vitro

Low-temperature plasma (LTP) has demonstrated great potential in biomedicine, especially cancer therapy in vivo and in vitro. Plasma activated water (PAW) as an indirect plasma therapy is a significant source of reactive oxygen and nitrogen species (RONS), which play a significant role in apoptosis induction in cancer cells. In this study, a Helium (He) plasma jet operating in 0.75 W dissipated power and 15 kHz frequency was used as cold atmospheric plasma source. The electrical, thermal, and optical properties of the (He) plasma jet, as well as the pH, conductivity, and temperature of the PAW samples, were investigated. Then, the concentration of hydrogen peroxide (H2O2), nitrite (NO2-), and nitrate (NO-3), which are produced in water as long-lived anti-cancer RONS, after 6 min of plasma treatment, was measured UV-Vis spectrophotometry 471.6, 7.9, and 93.5 μM, respectively. Alamar Blue and flow cytometry assays were employed to investigate the B16F10 cancer metabolic activity and apoptosis. The data support that cold atmospheric plasma (CAP) can produce an absolute concentration of anti-cancer agents in water and induce apoptosis in melanoma cancer cells due to delivered RONSs via activating the caspase 3 pathway.