Bulletin of the American Physical Society
72nd Annual Gaseous Electronics Conference
Volume 64, Number 10
Monday–Friday, October 28–November 1 2019; College Station, Texas
Session UF1: Biological Applications of Plasmas and Plasma Applications in Medicine |
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Chair: Alexander Fridman, Drexel University Room: Century I |
Friday, November 1, 2019 10:00AM - 10:15AM |
UF1.00001: Plasma-cell interaction: the role of plasma parameters Li Lin, Dayun Yan, Xiaoliang Yao, Vikas Soni, Jagadishwar Sirigiri, Michael Keidar After a decade of studies on the plasma-based cancer therapy in-vivo and in-vitro, it is clear that the reactive nitrogen-oxygen species play a key role in leading cells to apoptosis. However, in addition to the plasma direct therapeutic actions, we have found that plasma treatment leads to cell sensitization or activation. Such effect explains the mechanism of cold atmospheric plasma actions. In fact, recently we observed that the plasma activation depends on discharge parameters such as the discharge voltage. In this work, we summarize the role and behavior of the plasma parameters of a cold atmospheric plasma jet and their effect on cell activation and treatment. Moreover, we introduce the idea of the cell feedback control and the optimization of the emission as a part of the self-adaptive plasma which can be tailored for a variety of situations among different cell lines and patients. [Preview Abstract] |
Friday, November 1, 2019 10:15AM - 10:30AM |
UF1.00002: A possible mechanism of the selective effect of a non-equilibrium plasma on healthy and cancer cells in a physiological solution Mikhail Shneider, Mikhail Pekker A possible mechanism for the selective effect of weakly ionized nonequilibrium plasma and currents in electrolyte on healthy and cancerous cells in physiological saline in a Petri dish is considered. The interaction with the plasma source leads to a change in osmotic pressure [1], which affects the electro-mechanical properties of cell membranes in healthy and cancerous cells in different ways. The currents arising in the electrolyte charge the membranes of healthy and cancerous cells to a different potential difference due to the different values of the membranes' dielectric constant. We hypothesized that the dielectric permeability of cancer cell membranes is lower than that of healthy cells, as is the capacity of a unit of the membrane surface, and therefore, the additional potential difference acquired by the membrane through charging with currents induced in the intercellular electrolyte is greater in cancer cells. This can lead to electroporation of cancer cell membranes, resulting in their apoptosis, but does not affect healthy cells. 1. M.N. Shneider, M. Pekker, J. Appl. Phys. 123, 204701 (2018) [Preview Abstract] |
Friday, November 1, 2019 10:30AM - 10:45AM |
UF1.00003: Effects of Plasma-Generated Reactive Species with Different Working Gases on Reaction of Tyrosine Toshiro Kaneko, Maho Yanagisawa, Keisuke Takashima, Shota Sasaki Non-equilibrium atmospheric-pressure plasma (APP) has recently emerged as a novel tool in medicine and agriculture. Despite the promising potential, it has not yet become a breakthrough technology, because key plasma-generated species and action mechanisms remain unclear in most cases. The key species and mechanisms can be found through fundamental experiment on the interaction of the plasma-generated reactive species with biomolecules such as proteins (peptide, amino acids), phospholipids, and enzymes. In this study, we have examined the interaction of APP with tyrosine, which is one of the 20 standard amino acids and is known to play important roles in many cellular processes through chemical modifications such as nitrosylation and phosphorylation in protein. While observed absorption spectrum of tyrosine solution after He$+$H$_{\mathrm{2}}$O APP treatment was broadened to 600 nm, that after air plasma effluent treatment has a well-defined peak around 475 nm, in agreement with previously-reported spectrum of dopachrome. The plasma-generated reactive species delivered into solution is deduced to determine the reaction products. In the presentation, composition of gas-phase reactive species and reaction route with tyrosine in the liquid phase will be discussed. [Preview Abstract] |
Friday, November 1, 2019 10:45AM - 11:00AM |
UF1.00004: Synchronized Imaging and Spectroscopy of Atmospheric Pressure Plasma Bullets for Soft and Biomaterial Applications Ryan Gott, Kunning Xu Pulsed dc atmospheric pressure plasma jets are comprised of a series of fast moving plasma bullets. Plasma bullets are the front of ionization streamers and studying them can give insight to the characteristics of a plasma. In this work, the formation and lifetime of these bullets were observed using synchronized imaging with an ICCD camera. The bullets were studied at various voltages (6-10 kV), flow rates (1-6 slm), and pulse widths (500-2000 ns) to monitor changes in bullet velocity and distance traveled. The measured velocities of the plasma bullets were nonlinear for the lifetime of the bullet and were mainly dependent on voltage. Furthermore, an ICCD spectrometer was used to provide synchronized optical emissions spectroscopy measurements. The formation of reactive species such as OH and excited N$_{\mathrm{2}}$ (2$+)$ was observed at a nanosecond timescale. It was seen that OH forms only inside each bullet and rapidly dissipates after the bullet moves. The excited N$_{\mathrm{2}}$ species then form in the wake of the bullet and last for hundreds of nanoseconds. Observing the temporal formation of plasma bullets and reactive species allows us to understand how to tailor the plasma parameters for treatments of soft and biomaterials. [Preview Abstract] |
Friday, November 1, 2019 11:00AM - 11:15AM |
UF1.00005: Numerical study of plasma dynamics and temporal-spatial variation of O and OH concentrations in atmospheric pressure plasma jets impinging on different substrates Yuanyuan Jiang, Yanhui Wang, Dezhen Wang Atmospheric pressure plasma jets (APPJs) have been gaining attention because of their great potential in various fields, e.g. sterilization, surface process and plasma biomedicine. We explore the influence of gas flow rates and dielectric constant of the substrates on the jet structure and production and transportation of reactive oxygen species (O and OH) in direct-current voltage driven atmospheric pressure helium-nitrogen mixture plasma jet (propagating into humid air) for the humid air impurity level of 0.1{\%} using a 2D fluid model. Gas flow rates affects not only the structure of the APPJs, but also the concentration of the O and OH. The surface integrated flux of O and OH decreases with the increasing of gas flow rates due to the reduction of the air diffusion. When the permittivity of the substrate is raised, the propagation length of the surface ionization wave along the dielectric surface decreases, but the production of the reactive oxygen species and the surface integrated flux to the substrates increase. The results presented here can provide a clear understand on the applications of the APPJs for us. [Preview Abstract] |
Friday, November 1, 2019 11:15AM - 11:30AM |
UF1.00006: Air Plasma Generation with an Electrically Conductive Liquid Column Jet Keisuke Takashima, Kenji Nihei, Toshiro Kaneko For the plasma agricultural application, a liquid jet spray through an air plasma has been developed. An electrically conductive water solution jet with KNO$_{\mathrm{3}}$ is injected into a discharge domain and utilized as the grounded electrode to generate the plasma. This realizes significant power loading to the gas-liquid interface plasma and the plasma exposed liquid column jet collapses into droplets. Liquid phase reactive oxygen and nitrogen species (RONS$_{\mathrm{aq}})$ and the gas phase RONS$_{\mathrm{gas}}$ are experimentally characterized by reagent test kits and FTIR, respectively. The experimental characterization on the OH$_{\mathrm{aq}}$ production indicates that most of OH$_{\mathrm{aq}}$ can be generated near the liquid surface. The gas-liquid interface reactions can be significantly modulated by the liquid flow rate, inferred from the measured gas phase RONS$_{\mathrm{gas}}$ composition. Conidium suspension liquid droplets are sprayed by the plasma exposed solution to evaluate the antibacterial effect of the plasma exposed solution. The generated NO$_{\mathrm{2gas}}$ density founds to be well related to the conidium germination suppression effect under a similar OH$_{\mathrm{aq}}$ generation. Therefore, the gas-liquid interface reactions generating RONS are considered to play an important role on suppressing the conidium germination. [Preview Abstract] |
Friday, November 1, 2019 11:30AM - 11:45AM |
UF1.00007: Filling Data Gaps Related to Material Effects in Polymer Medical Products from E-beam and X-ray Sterilization Min Huang, Md. Kamrul Hasan, David Staack, Matt Pharr Gamma ray treatment predominates among current medical device radiative sterilization methods. However, there are potential nuclear security concerns associated with Colbalt-60 gamma radiation; E-beam and X-ray methods may serve as safe future alternatives. To this end, 88 samples of medical devices (vacutainer (VT) and push button (PB)) and 2000 dog bones made of polyvinyl chloride (PVC), polypropylene homopolymer (PPH), polyethylene terephthalate (PET), low-density polyethylene (LDPE), polyolefin elastomer (POE) and chlorinated isobutylene isoprene rubber (CIIR) have been irradiated by gamma ray, X-ray, and E-beam with doses ranging from 0kGy to 80kGy. Functionality of the medical products was tested before and after treatment, and raw material tensile strength and hardness was measured. Yellowness index measurements indicate no dependence on irradiation modality; color variation depends on type of polymer and dose, since component polymers respond differently to treatment (formation of carbonyl species, double bonds, conjugated free radicals). Overall, the investigated relationship between type of radiation source and observed chemical and physical changes show that E-beam and X-ray are safe alternatives to gamma ray sterilization of medical products. [Preview Abstract] |
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