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Nonthermal plasma processes recently emerged as promising therapeutic tools for the treatment of cancer. Most anticancer effects of plasma have been related to the induction of oxidative stress due to the release of reactive oxygen and nitrogen species (RONS), among other plasma components, during discharge. The exact mechanism of action in the eradication of cancer, though, is still far from being fully understood. In this research, three cancer-derived cell lines were exposed to pulsed dielectric barrier discharge (DBD) to investigate the effect of direct plasma exposure on cancer cells. Among many cellular functions, cell adhesion and morphology were found to be visibly influenced. Morphological assays showed the inhibition of intercellular adhesion, losses in cell clustering, and changes in the external shape and actin cytoskeleton. These effects were related to the decrease in cell viability and plasma operational conditions. The increased expression of the heat shock protein HSP70 in plasma-exposed Saos2 cells confirmed that changes in morphology and viability in cancer cells are representative of internal changes in the oxidative state of cells that are caused by plasma-induced oxidative stress.

Plasma Treated Water Solutions (PTWS) recently emerged as a novel tool for the generation of Reactive Oxygen and Nitrogen Species (ROS and RNS) in liquids. The presence of ROS with a strong oxidative power, like hydrogen peroxide (H2O2), has been proposed as the main effector for the cancer-killing properties of PTWS. A protective role has been postulated for RNS, with nitric oxide (NO) being involved in the activation of antioxidant responses and cell survival. However, recent evidences proved that NO-derivatives in proper mixtures with ROS in PTWS could enhance rather than reduce the selectivity of PTWS-induced cancer cell death through the inhibition of specific antioxidant cancer defenses. In this paper we discuss the formation of RNS in different liquids with a Dielectric Barrier Discharge (DBD), to show that NO is absent in PTWS of complex composition like plasma treated (PT)-cell culture media used for in vitro experiments, as well as its supposed protective role. Nitrite anions (NO2-) instead, present in our PTWS, were found to improve the selective death of Saos2 cancer cells compared to EA.hy926 cells by decreasing the cytotoxic threshold of H2O2 to non-toxic values for the endothelial cell line.

Astrocyte proliferation and migration toward injured Central Nervous System (CNS) areas are key features of astrogliosis and glial scar formation. Even though it is known that intracellular and environmental Reactive Oxygen and Nitrogen Species (RONS) affect astrocyte behaviour in physiological and pathophysiological conditions, their effects on the migration and growth of astrocytes are still unclear. Plasma-technologies are emerging in medicine as a tool to generate RONS for treating cells directly or through Plasma Activated Liquid Media (PALM). In this paper, we show for the first time how the use of PALM can modulate both astrocyte growth and migration as a function of active species produced by plasma in liquids. Our results show that PALM, generated by means of cold atmospheric pressure plasmas fed with N2, air or O2, can modulate astrocyte behaviour depending on the content of hydrogen peroxide and nitrite in the liquid. In particular, H2O2 enriched PALM induced a negative effect on cell growth associated with the mild wound healing improvement of primary astrocytes, in a scratch assay. Nitrite enriched PALM induced a selective effect on the wound healing without affecting cell growth. PALM containing a more balanced level of H2O2 and NO2&minus, were able to affect cell growth, as well as significantly ameliorate wound healing. None of the PALM investigated induced upregulation of the gliotic inflammatory marker glial fibrillary acidic protein (GFAP), or of the astrocyte markers Aquaporin-4 (AQP4) and Connexin-43 (Cx-43) analysed by Western blot. Finally, immunofluorescence analysis revealed the presence of NO2- able to induce elongated protrusions at the front end of wounded astrocytes in the direction of cell migration. With our study we believe to have shown that PALM offer a novel tool to modulate astrocyte behaviour and that they are promising candidates for controlling astrogliosis in the case of CNS injuries.

Oxygen plasma etching of polytetrafluoroethylene has been investigated as a way to sculpture nano-features on its surface and producing a super-hydrophobic material in one step. It has been found that, depending on the experimental conditions, the shape of the structures engraved in the polymer surface passes from pyramidal to unique pyramids with well-defined spherules on the top. The latter are obtained without any mask/lithographic option. In a previous paper the water repellent character of such etched polytetrafluoroethylene surface has been well documented and explained by some of the authors. In this paper, instead, some insights in the formation mechanism of such unusual morphology are provided. Chemical and morphological characterization indicate in the iron surface contamination the clue for the formation of such complex agglomerates.