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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.

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.

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.

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.