An investigation of the anti-cancer effect of underwater air jets with different grounding methods

With the wide application of plasma-treated activated water in biomedicine in recent years, people have begun to explore how to prepare activated water efficiently. In this paper, we introduce a new idea of underwater plasma air jet to prepare activated water for anticancer use. Meanwhile, we compared the anticancer effect of underwater discharge of two different structural devices by changing the position of grounded electrodes. We photographed the evolution of the underwater jet using a high-speed camera and measured the generated free radicals by an emission spectrometer. We measured the physicochemical properties, including pH, oxidation–reduction potential, temperature, O₃ concentration, and some active particles in the liquid-phase reaction, such as H₂O₂, NO₂⁻, and NO₃⁻, and the concentration of these active particles can indirectly reflect the anticancer effect. We use the activated water mixed medium to treat the cells for a certain period of time and test their activity after a period of time. Results show that the underwater discharge device with two grounding methods has a better anti-cancer effect. In order to find out the specific response of activated water against cancer, we measured the apoptosis and the concentration of intracellular reactive oxygen species (ROS) and found that the apoptosis rate of cells treated with activated water increased significantly and the concentration of intracellular ROS also increased. Therefore, the preparation of activated water by underwater air jets for anticancer purposes may be a novel plasma anticancer method.