Bulletin of the American Physical Society
67th Annual Gaseous Electronics Conference
Volume 59, Number 16
Sunday–Friday, November 2–7, 2014; Raleigh, North Carolina
Session ET1: Plasma Diagnostics and Sources for Biological Applications |
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Chair: Toshiro Kaneko, Tohoku University Room: State EF |
Tuesday, November 4, 2014 1:30PM - 1:45PM |
ET1.00001: Multi-Modality Pulsed AC Source for Medical Applications of Non-Equilibrium Plasmas Daniel Friedrichs, James Gilbert A burgeoning field has developed around the use of non-equilibrium (``cold'') plasmas for various medical applications, including wound treatment, surface sterilization, non-thermal hemostasis, and selective cell destruction. Proposed devices typically utilize pulsed DC power sources, which have no other therapeutic utility, and may encounter significant regulatory restrictions regarding their safety for use in patient care. Additionally, dedicated capital equipment is difficult for healthcare facilities to justify. In this work, we have demonstrated for the first time the generation of non-equilibrium plasma using pulsed AC output from a specially-designed electrosurgical generator. The ability to power novel non-equilibrium plasma devices from a piece of equipment already ubiquitous in operating theatres should significantly reduce the barriers to adoption of plasma devices. We demonstrate the ability of a prototype device, coupled to this source, to reduce bacterial growth in vitro. Such a system could allow a single surgical instrument to provide both non-thermal sterilization and thermal tissue dissection. [Preview Abstract] |
Tuesday, November 4, 2014 1:45PM - 2:00PM |
ET1.00002: Selective irradiation of radicals for biomedical treatment using vacuum ultraviolet light from an excimer lamp Ryo Ono, Yusuke Tokumitsu, Shungo Zen, Seiya Yonemori In plasma medicine, radicals are considered to play important roles. However, the medical effect of each radical, such as OH and O, is unknown. To examine the effect of each radical, selective production of radicals is needed. We developed selective production of radicals for biomedical treatment using a vacuum ultraviolet (VUV) light emitted from an excimer lamp. Selective irradiation of OH radicals can be achieved by irradiating the 172-nm VUV light from a Xe$_{\mathrm{2}}$ excimer lamp to a humid helium flow in a quartz tube. The water molecules are strongly photodissociated by the VUV light to produce OH radicals. A photochemical simulation for the selective OH production is developed to calculate the OH density. The calculated OH density is compared with OH density measured using laser-induced fluorescence (LIF). Selective production of other radicals than OH is also discussed. [Preview Abstract] |
Tuesday, November 4, 2014 2:00PM - 2:15PM |
ET1.00003: Diagnostic Challenges in Plasma Medicine Stephan Reuter, Helena Tresp, Ansgar Schmidt-Bleker, Joern Winter, Sylvain Iseni, Mario D\"unnbier, Kai Masur, Annemarie Barton, Malte Hammer, Thomas von Woedtke, Klaus-Dieter Weltmann Atmospheric plasmas exhibit large gradients in space and time. This challenges diagnostics such as LIF or other quantitative species detection methods. Bringing these plasmas in contact with liquids generates further complex processes which influence reactive component generation in the plasma, gas- and liquid phase. For plasma medicine, the transfer through these phases to the cell is the task for diagnostics. In the present work, several approaches of plasma, gas and liquid diagnostics such as LIF, absorption spectroscopy, colorimetric assays or EPR spectroscopy are discussed and it is shown how a careful study of the processes can lead to an at least partial understanding of plasma interaction with biological cells. [Preview Abstract] |
Tuesday, November 4, 2014 2:15PM - 2:30PM |
ET1.00004: Measurement of OH, NO, O and N atoms in helium plasma jet for ROS/RNS controlled biomedical processes Seiya Yonemori, Taku Kamakura, Ryo Ono Atmospheric-pressure plasmas are of emerging interest for new plasma applications such as cancer treatment, cell activation and sterilization. In those biomedical processes, reactive oxygen/nitrogen species (ROS/RNS) are said that they play significant role. It is though that active species give oxidative stress and induce biomedical reactions. In this study, we measured OH, NO, O and N atoms using laser induced fluorescence (LIF) measurement and found that voltage polarity affect particular ROS. When negative high voltage was applied to the plasma jet, O atom density was tripled compared to the case of positive applied voltage. In that case, O atom density was around 3 $\times$ 10$^{15}$ [cm$^{-3}$] at maximum. In contrast, OH and NO density did not change their density depending on the polarity of applied voltage, measured as in order of 10$^{13}$ and 10$^{14}$ [cm$^{-3}$] at maximum, respectively. From ICCD imaging measurement, it could be seen that negative high voltage enhanced secondary emission in plasma bullet propagation and it can affect the effective production of particular ROS. Since ROS/RNS dose can be a quantitative criterion to control plasma biomedical application, those measurement results is able to be applied for \textit{in vivo} and \textit{in vitro} plasma biomedical experiments. [Preview Abstract] |
Tuesday, November 4, 2014 2:30PM - 2:45PM |
ET1.00005: Vacuum ultraviolet spectroscopic analysis of AC excited non-equilibrium atmospheric pressure Ar plasma jet Keigo Takeda, Kenji Ishikawa, Hiromasa Tanaka, Hiroki Kondo, Makoto Sekine, Masaru Hori Plasma biomedical treatments with atmospheric pressure plasma jets (APPJ) have attracted very much. In the treatments, reactive species and high energy photons emitted from APPJ are important factors to realize the performance. Vacuum ultraviolet (VUV) spectroscopy is one of useful techniques to measure quantitative behaviors of atomic radicals and high energy photons. In this study, an AC excited APPJ with Ar gas has been investigated by using the spectroscopy. The Ar APPJ was generated under open air condition, and VUV emission spectra was measured by using a VUV monochromator. The spectra of atomic species such as O (130.4 nm), N (120.0, 174.3 nm), and H (121.6 nm) were observed. The emission intensity of N atom (174.3 nm) in the plasma remote region exponentially decreased with increasing the distance from the plasma jet. The absorption coefficient was estimated to be 1.8 cm$^{-1}$, over 20 mm distance from the plasma jet, the coefficient increase to 4.2 cm$^{-1}$ which is almost same with value due to atmosphere. We will discuss behaviors of reactive species and high energy photons emitted from the AC excited Ar APPJ on the basis of the results measured by VUV spectroscopy. [Preview Abstract] |
Tuesday, November 4, 2014 2:45PM - 3:00PM |
ET1.00006: Non thermal plasma jets interacting with targets and gas flows Eric Robert, T. Darny, D. Ries, S. Dozias, J-M. Pouvesle Non thermal plasma jets at atmospheric pressure have been recently used in an impressive number of works including plasma diagnostics, biomedical treatments and material processing. While the plasma source setups are very simple, it has been evidenced that many parameters may significantly influence the plasma characteristics offering at the same time a large versatility for plasma delivery but also requiring a special attention to match the plasma features for any specific application. In this work, emphasis will be given on two critical topics involved in any plasma jet biomedical applications. The first consists in the influence of the target over which plasma jet impinges. It has been shown that depending on the conductivity of the target, secondary plasma generation occurs, leading to a critical modification of the reactive species generation. The second main issue concerns the strong interplay between the rare gas flow and the plasma species generated during plasma jet ionization wave propagation. Drastic modification of the rare gas flow features have been recently characterized through Schlieren visualization and ICCD imaging [1].\\[4pt] [1] E. Robert, V. Sarron, T Darny, D. Ri\`{e}s, S. Dozias, J Fontane, L. Joly and J.M. Pouvesle, \textit{Rare gas flow structuration in plasma jet experiment,} Plasma Sources Sci. Technol. 23 0120003 (2014). [Preview Abstract] |
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