Terahertz is a new radiation source with many unique advantages. In recent years, its application has rapidly expanded to various fields, but there are few studies on the individual effects of terahertz. In this study, we investigated the behavioral effects of terahertz radiation on C57BL/6 mice, and we conducted an open field test, an elevated plus maze test, a light–dark box test, a three-chamber social test, and a forced swim test to explore the effects of terahertz radiation on mice from a behavioral perspective. The results show that terahertz wave may increase anti-anxiety, anti-depression, and social interaction in mice.

In recent years, the emerging technology of cold atmospheric pressure plasma (CAP) has grown rapidly along with the many medical applications of cold plasma (e.g., cancer, skin disease, tissue repair, etc.). Plasma-activated liquids (e.g., culture media, water, or normal saline, previously exposed to plasma) are being studied as cancer treatments, and due to their advantages, many researchers prefer plasma-activated liquids as an alternative to CAP in the treatment of cancer. In this study, we showed that plasma-activated-saline (PAS) treatment significantly inhibited tumor growth, as compared with saline, in melanoma, and a low-pH environment had little effect on tumor growth in vivo. In addition, based on an ultra-high-performance liquid tandem chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) analysis of tumor cell metabolism, the glycerophospholipid metabolic pathway was the most susceptible metabolic pathway to PAS treatment in melanoma in vitro and in vivo. Furthermore, PAS also inhibited cell proliferation in vivo in oral tongue squamous-cell cancer and non-small-cell lung cancer. There were few toxic side effects in the three animal models, and the treatment was deemed safe to use. In the future, plasma-activated liquids may serve as a potential therapeutic approach in the treatment of cancer.

In the field of plasma biomedicine, research on a plasma-activated medium (PAM) has attracted increasing attention in recent years because of its excellent characteristics. In this study, we used an atmospheric pressure air plasma jet to treat four different solutions: de-ionized water, RPMI 1640 medium, phosphate buffered saline (PBS), and saline. In order to investigate the property differences of different PAM, we mainly analyzed the physical and chemical properties and liquid-phase active species of different PAM and evaluated the inactivation of A549 lung cancer cells. The results show that the concentrations of long-lived reactive species (H2O2, NO2−, and NO3−) in different PAM increased with increasing treatment time. Biological experiments showed that the antitumor effects were in the order of PBS > saline > RPMI 1640 medium, and the best inactivation effect of plasma-activated PBS for 12 min was 89%. Meanwhile, plasma-activated PBS effectively promoted apoptosis in A549 cells, and the highest apoptosis rate was 91.3%. Therefore, this study demonstrates the medical application of different PAM in killing cancer cells and promotes the understanding of plasma–liquid interaction.

Nanosecond-pulse power has the characteristics of quickly increasing applied power, short pulse width, and considerably high-energy electrons. In this study, we investigated the different air/helium mixture ratios of nanosecond-pulsed-power-driven plasma jet discharge characteristics and the physicochemical properties of the gaseous and aqueous phases. Results showed that the length and luminescence intensity of the plasma increased with decreasing air ratio. Notably, there is a maximum inflection point in N2O5 of Fourier transform infrared spectrometry detection and concentration of H2O2 at 70% air ratio. Furthermore, we used drug-resistant ovarian cancer cells (A2780/ADR) as a model to detect the anticancer effect, with the results indicating that 70% air ratio is the best condition to inhibit cell growth and induce cell apoptosis. Our research indicates that the air discharge driven by a nanosecond-pulse power supply has potential application in an ovarian cancer drug-resistant tumor cell therapy.

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.