Human colorectal cancer cell lines (HT29 and HCT116) were exposed to dielectric barrier discharge (DBD) plasma at atmospheric pressure to investigate the anticancer capacity of the plasma. The dose- and time-dependent effects of DBDP on cell viability, regulation of transcription factor Sp1, cell-cycle analysis, and colony formation were investigated by means of MTS assay, DAPI staining, propidium iodide staining, annexin V–FITC staining, Western blot analysis, RT-PCR analysis, fluorescence microscopy, and anchorage-independent cell transformation assay. By increasing the duration of plasma dose times, significant reductions in the levels of both Sp1 protein and Sp1 mRNA were observed in both cell lines. Also, expression of negative regulators related to the cell cycle (such as p53, p21, and p27) was increased and of the positive regulator cyclin D1 was decreased, indicating that the plasma treatment led to apoptosis and cell-cycle arrest. In addition, the sizes and quantities of colony formation were significantly suppressed even though two cancer promoters, such as TPA and epidermal growth factor, accompanied the plasma treatment. Thus, plasma treatment inhibited cell viability and colony formation by suppressing Sp1, which induced apoptosis and cell-cycle arrest in these two human colorectal cancer cell lines.

A transparent superhydrophobic surface on glass is prepared by a rapid single‐step method using a He, CH4, C4F8 mixture plasma at atmospheric pressure. Water droplet contact angles and surface properties are investigated to analyze both chemical and physical characteristics of the plasma treated surfaces. As the C4F8 gas flow rate is increased in the He/CH4 plasma, both advancing, and receding water contact angles are increased, while UV‐visible transmittance is degraded. By optimizing the gas mixture ratio, we find rapid deposition conditions for superhydrophobic formation without losing the visible to near‐infrared transparency of the glass. The chemical and physical mechanism responsible for hydrophobicity is also discussed through the investigation of chemical composition and surface morphology.

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Front Cover: Teflon‐like plasma polymerization on a glass surface was made by simple and fast atmospheric pressure plasma treatment. Variation of feeding gas ratio such as CH4 and C4F8 enables to control transparency and hydrophobicity by changing in both chemical composition and physical morphology of the glass surface. The SEM image showed multi‐scale structure, and the glass surface was transparent keeping its hydrophobicity. Further details can be found in the article by Se Youn Moon et. al. http://doi.wiley.com/10.1002/ppap.201400145.

Facilitating the separate production of ozone (O3) and nitrogen oxides (NO x ) in air discharges without a thermal process is of most merit in diversifying plasma technology; in particular, it is a primary requirement in certain cold, heat-sensitive plasma applications. Here, we propose a new method of nonheating ozone suppression in air discharges. The present work demonstrates that controlling the plasma chemical kinetics by adjusting the duration (width) and/or repetition frequency of the high-voltage DC pulse is effective in suppressing ozone formation in a surface dielectric barrier discharge in static ambient air. The temporal development of each oxygen- and nitrogen-related species in air discharge is complicated and shows different trends in the time range <10 µs; relatively long-lived O3 and NO x are strongly governed by the temporal behavior of short-lived reactive species, such as excited N2(A) and N2(v). To quantify time-varying O3 and NO x , an in situ UV absorption spectroscopy is applied to our gas-tight plasma reactor, which is operated in air at 21 °C. With a fixed frequency at 10 kHz and decreasing pulse duration from 10 μs to 0.18 μs, ozone is quenched faster in the plasma reactor, resulting in an irreversible chemical mode transition from an O3- to NO-rich environment. From a different set of experiment (with a 200 ns pulse duration and a frequency range of 1–10 kHz), we can conclude that the off-pulse period also plays a crucial role in the temporal evolution of O3 and NO x ; the larger the applied driving frequency is, the earlier the ozone-free phenomenon appears over the discharge time. Our findings represent a breakthrough in expanding the usage of air discharges and their application in various fields of interest.