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The characteristics of plasma activated medium (PAM) and its different effects on cancer and normal cells are a relevant topic of study in the field of plasma medicine. In this study, an atmospheric pressure plasma jet (APPJ) with helium was applied for generating PAM, which was utilized for malignant melanoma (B16) and normal fibroblast (3T3) cell treatment. With the applied peak–peak voltages of 8, 10, and 12 kV, together with the gas flow rates of 1, 2, and 3 L/min, the characteristics of He APPJ and PAM were investigated, respectively. The results showed that compared with the free-standing jet, both the total power that was dissipated into the APPJ device and the emission intensities of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the gas phase increased when it interacted with the medium. There were obvious increases of H2O2 and ${\mathrm {NO}}_{2}^{-}$ in PAM with different APPJ activation time of 5, 10, 15, 30, 45, and 60 s. The gas flow rate did not yield significant differences in the concentration of species generated, the applied voltage being a more relevant parameter. Finally, the results of cell viability and cell apoptosis assay indicated that the identical dose PAM had a selective effect on two kinds of nonhomologous cells.

PM

In this study, Eriochrome Black T (EBT) in water was decolorized by means of argon atmospheric pressure plasma jet (APPJ), which showed great decolorization performance. The results showed that the relatively high decolorization rate (approximately 80%) was obtained after plasma treatment for 6 min. Changes to some reactive oxygen and nitrogen species (RONS) in the liquid phase were detected. The contents of peroxide, HO·, O2−·, and NO· in the plasma-treated EBT solution were much less than those in the activated water. The roles of H2O2 and HO· in the decolorization of EBT solution were explored by evaluating the effects of their scavengers, and by exploring the direct effect of H2O2. The results indicated that reactive oxygen species (ROS), especially HO· and O2−·, played significant roles in the decolorization of the EBT solution. Analysis of degradation by-products indicated that plasma discharge could destroy the azo bond first and gradually break the aromatic rings of EBT molecules into small molecular compounds.

This paper is aimed to identify the mechanism that atmospheric pressure plasma jet (APPJ) damages malignant melanoma (B16-BL6 cells) cultured in vitro through the induction of oxidative stress. After being exposed to APPJ with different time durations, the reactive species of H 2 O 2 and NO 2 - inside cell culture medium, together with a series of biochemical parameters including the cell viability, cell morphology, DNA damage, intracellular reactive oxygen species (ROS) and antioxidant capacity, are measured. The results reveal that there are obvious increases of H 2 O 2 and NO 2 - in the plasma-irradiated medium. And the cell viability, intracellular total antioxidant capability (T-AOC), and glutathione (GSH) contents decrease with the exposure to APPJ in a time-dependent manner compared with the untreated cells, i.e., 0-s group (p

An argon atmospheric pressure plasma jet was employed to treat L929 murine fibroblasts cultured in vitro. Experimental results showed that, compared with the control cells, the treatment of fibroblasts with 15 s of plasma led to a significant increase of cell viability and collagen synthesis, while the treatment of 25 s plasma resulted in a remarkable decrease. Exploration of related mechanisms suggested that cold plasma could up-regulate CyclinD1 gene expression and down-regulate p27 gene expression at a low dose, while it could down-regulate CyclinD1 expression and up-regulate p27 expression at a higher dose, thus altering the cell cycle progression, and then affecting cell viability and collagen synthesis of fibroblasts.

The potential applications of low temperature plasma (LTP) in wound healing have aroused the concern of many researchers. In this study, an argon atmospheric pressure plasma jet was applied to generate LTP for treatment of murine fibroblast cell (L929) cultured in vitro to investigate the effect of NF-κB pathway on fibroblast proliferation. The results showed that, compared with the control, L929 cells treated with plasma for less than 20 s had significant increases of proliferation; the productions of intracellular ROS, O2− and NO increased with prolongation of LTP treatment time; NF-κB pathway was activated by LTP in a proper dose range, and the expression of cyclinD1 in LTP-treated cells increased with the same trend as cell proliferation. After RNA interference to block p65 expression, with the same treatment time, RNAi-treated cells proliferated more slowly and expressed less cyclinD1 than normal cells. Furthermore, pretreatment with N-acetyl-L-cysteine (NAC) markedly prevented the plasma-induced changes in cells. In conclusion, the proliferation of L929 cells induced by LTP was closely related to NF-κB signaling pathway, which might be activated by appropriate level of intracellular ROS. These novel findings can provide some theoretical reference of LTP inducing cell proliferation and promoting wound healing.

Atmospheric pressure cold plasma that contains numerous act ive components including electrons, ions, free radicals, reacti ve molecules and photons has been extensively researched as a promising anticancer treatment technology in recent years1. Melanoma is the most aggressive form of skin cancer with a high prevalence, a median overall survival of less than 2 year s, and resistance to current modalities of cancer therapy2. Plas ma can inactivate melanoma caner cells effectively, but the m echanism of the interaction between plasma and cells is not y et fully understood and needs to be investigated further. In this work, an improved atmospheric pressure plasma jet (A PPJ) with three electrodes in helium was utilized for treatmen t of murine melanoma caner cells cultured in vitro. After bein g exposed to APPJ with different time durations, the cell viab ility, transmission electron microscopy (TEM) images, intrac ellular superoxide dismutase (SOD), malondialdehyde (MD A), reactive oxygen species (ROS) and cell cycle distribution of melanoma cells were measured, respectively. It was show ed that, compared with the control cells, the cell viability and SOD activity decreased, the degree of cell damage, MDA an d ROS content increased in a time-dependent manner with 10, 30, and 60 s of plasma treatment. Furthermore, the APPJ ma y reduced cell viability of melanoma cells via inducing G1/S and G2/M cell cycle arrest. It was concluded that oxidative st ress in melanoma cells was mainly induced by the reactive ox ygen and nitrogen species (ROS and RNS) in the plasma jet, which were detected by optical emission spectroscopy.

Studies discovered that Low temperature plasma (LTP) could promote wound healing. However, the detailed mechanisms in the cellular and molecular levels are still not fully understood. In this study, an atmospheric pressure discharge plasma jet in flowing argon by means of dielectric barrier discharge (DBD) was used to treat murine fibroblasts cultured in vitro, in order to explore the molecular mechanism of cold plasma on cell viability and collagen synthesis. Experimental results showed that, compared with the control cells, the treatment of fibroblasts with 15 s of plasma led to a significant increase of cell viability and collagen synthesis, while the treatment of 25 s plasma resulted in a remarkable decrease. Exploration of related mechanisms suggested that cold plasma could up-regulate CyclinD1 gene expression and down-regulate p27 gene expression at a low dose, while it could down-regulate CyclinD1 expression and up-regulate p27 expression at a higher dose, thus altering the cell cycle progression, and then affecting cell viability and collagen synthesis of fibroblasts.