Hollow electrode plasma jet array: effects of O2 concentration on He-N2-O2 plasma jets and inactivation effect on cancer cell

Abstract Hollow electrode discharge is commonly utilized across various fields, but the research on hollow electrode discharge plasma jet array and its corresponding anticancer effect remains limited, especially their induced liquid chemistry and biological effects. This study describes the generation of plasma multi-jet through a novel-designed hollow electrode array generator and the anticancer effect of plasma-activated water (PAW) through multi-jet treatment. The rise of O2 concentration has affected the discharge morphology, electrical characteristics, and gaseous reactive species generation, resulting in differences in the liquid-phase chemical properties of PAW. Among these, the N2-related gaseous emissive species decrease with the rise of the O2 ratio, while the O-related species show a first increasing and then decreasing trend. Furthermore, the PAW produced under 0% of O2 contains more ONOO- and O- 2 species, while the PAW generated under 0.3% O2 contains more H2O2 and NO- 2 species. On this basis, the PAW generated at a relatively low O2 percentage (0% and 0.3%) results in a higher inactivation efficiency against cancer cells due to the high concentrated H2O2, NO2-, and ONOO−/O2-. This study offers insights into the design of plasma generation devices and the preparation of PAW for practical tumor therapy.