Properties and anticancer effects of plasma-activated medium stored at different temperatures

Abstract

Plasma-activated solution (PAS) has attracted wide attention in cancer treatment because it can treat deep tumors and offer storability. The changes in reactive species and physicochemical properties of PAS during storage can affect its anticancer effect. In this study, the plasma-activated medium (PAM) was prepared by treating RPMI 1640 medium with afterglow gas generated by a custom-built air surface dielectric barrier discharge device. PAM was stored at four common temperature conditions (25 °C, 4 °C, −20 °C, and −80 °C) for 1 day, 4 days, and 7 days, and then, the physicochemical properties, reactive oxygen and nitrogen species (RONS), and the anti-cancer effect on A549 cells under different storage conditions were compared. The results showed that PAM exhibited different anticancer effects at different storage temperatures over a 7 day storage period. The anticancer ability of PAM under 80 °C storage remained stable after 7 days of storage and decreased at all other temperatures. These results were also verified by apoptosis results, and the differences were mainly related to the concentration of H2O2 and NO2−, and oxido reduction potential. Our results provided a theoretical basis for the storage of PAM and its application in anticancer therapy.