Bulletin of the American Physical Society
74th Annual Gaseous Electronics Conference
Volume 66, Number 7
Monday–Friday, October 4–8, 2021;
Virtual: GEC Platform
Time Zone: Central Daylight Time, USA
Session JW63: Plasmas for Biomedical Applications |
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Chair: Katharina Stapelmann, North Carolina State University Room: Virtual GEC platform |
Wednesday, October 6, 2021 2:00PM - 2:30PM |
JW63.00001: Adaptive Plasmas for Plasma Medicine Invited Speaker: Michael Keidar The uniqueness of plasma is in its ability to change composition in situ [1,2,3]. Plasma self-organization could lead to formation of coherent plasma structures. These coherent structures tend to modulate plasma chemistry and composition, including reactive species, the electric field and charged particles. Formation of coherent plasma structures allows the plasma to adapt to external boundary conditions, such as different cells types and their contextual tissues. In this talk we will explore possibilities and opportunities that the adaptive plasma therapeutic system might offer. We shall define such an adaptive system as a plasma device that is able to adjust the plasma composition to obtain optimal desirable outcomes through its interaction with cells and tissues. We propose various approaches for plasma therapy based on plasma adaptation to target conditions. This approach is based on the ability of measuring the cellular response to plasma immediately after treatment and modifying the composition and power of plasma via a feedback mechanism. Plasma self-adaptation might be feasible due to self-organization and pattern formation when plasma interacts with targets. Plasma effect on cancer cells is influenced by various factors including the plasma jet discharge voltage, gas composition, humidity and cancer cell type [4]. To address this, we present an optimal feedback control scheme to adjust treatment conditions responsive to the actual cancer cell response [5]. |
Wednesday, October 6, 2021 2:30PM - 2:45PM |
JW63.00002: Cold plasma-driven biomolecule modifications - key or lock to effectiveness? Kristian Wende, Sebastian Wenske, Zahra Nasri, Mehdi Ravandeh, Klaus-Dieter Weltmann, Sander Bekeschus, Thomas von Woedtke In order to optimize the reactive species output of plasma sources for biomedical purposes, their ability to modify biomolecules was investigated in a series of in vitro-, in vivo, and ex-vivo experiments. The incorporation of gas-phase and liquid phase-derived atoms was observed [1], yielding new chemical groups. Peptides and proteins were found to serve as major targets [2] besides lipids that mainly underwent cleavage reactions [3]. Most reactions took place at the gas-liquid or gas-soft matter interface, indicating that transport processes at the interface are a limiting factor and penetration of chemically active short-lived species remain low. The molecular or structural functionality of the respective models was compromised by the impact of the plasma, e.g. the enzymatic activity of phospholipase A2 was reduced or lipid bilayers turned leaky. By the use of scavengers and mechanistic considerations, atomic oxygen and singlet oxygen were found most relevant. Reactive nitrogen species contributed to a minor extent. |
Wednesday, October 6, 2021 2:45PM - 3:00PM |
JW63.00003: Stability of Primary Amine Groups During Plasma Polymerization for the Surface Modification of Artificial Bones Anjar Anggraini A Harumningtyas, Tomoko Ito, Satoshi Sugimoto, Michiro Isobe, Joe Kodama, Takashi Kaito, Lenka Zajickova, Satoshi Hamaguchi The surface modification of calcium-phosphate artificial bones was performed with amine-containing polymer deposition by low-pressure pulsed plasmas [1-3]. It has been experimentally demonstrated to improve bone regeneration when the treated bones are implanted in animals [3]. The goal of this study is to examine the possibility of increasing the amount of amine embedded in the deposited polymer film. The experimental study of amine-containing polymer deposition showed that the ratio of the number of primary amine groups (-NH2) to the number of carbon (C) atoms in a plasma-deposited hydrocarbon film was typically about 3 % even in the presence of a relatively high amount of hydrogen (H) atoms in the plasma. In this study, we used molecular dynamics (MD) simulations [4] to examine how amine groups can be formed in a plasma polymerization process. Considering a methane (CH4) and nitrogen (N2) plasma process, we examined the effects of incident CH2 or CH3 radicals, NH2 radicals, and CH2+ or CH3+ energetic ions on the amine formation. The simulations showed that H atoms of incident NH2 radicals tended to react with surrounding C atoms in the polymerization process, resulting in the formation of secondary amine groups (-NH). The results were thus qualitatively consistent with the experimental observation that only a small percentage of primary amines were formed in plasma deposited hydrocarbon films. |
Wednesday, October 6, 2021 3:00PM - 3:15PM |
JW63.00004: Investigation of Reactive Species in NaCl Solution by One-Dimensional Reaction-Diffusion Numerical Simulation Enggar Alfianto, Satoshi Hamaguchi, Kazumasa Ikuse In applications of low-temperature gas plasmas in medicine and biology, various chemical species are generated by atmospheric pressure plasma (APP) in air. The chemical species generated in the gas phase such as H2O2, O, O2, and O3 interact with a liquid solution before reaching the tissue cells. Some of them are highly reactive and may be converted to other species in the liquid. This study focuses on the reactions and transport of plasma-generated species in liquid and examines their dynamics in NaCl solution with pH buffer. The numerical simulations were performed based on the one-dimensional (1-D) reaction-diffusion-advection equation.[1,2] Our goal is to find the dynamics of depth profiles of plasma-generated reactive species in NaCl solution and understand the validity of the corresponding zero-dimensional (global) simulations. The species of our interest were H2O2 (1.49x1012 cm-3) and O (0 - 1.49x1013 cm-3) in the gas phase.[3] The plasma irradiation time was 5 seconds. The 1-D simulation results showed that the concentration of H2O2 in the NaCl solution decreased when the amount of O from the plasma increased, as in the global simulation. O supplied from the gas phase reacts with Cl- in the solution forming ClO-species, which then reacts with H2O2 to produce H2O, O2, Cl- by-products. In the 1-D simulation, the decomposition of H2O2 by ClO- species mostly occurs near the gas-water boundary, typically within the depth of 250mm under the conditions examined here. |
Wednesday, October 6, 2021 3:15PM - 3:30PM |
JW63.00005: Selective plasma synthesis of dinitrogen pentoxide and ozone for sterilization and virus inactivation Toshiro Kaneko, Hiroto Iwamoto, Shota Sasaki, Keisuke Takashima, Hideki Takahashi The dinitrogen pentoxide (N2O5) is attractive for wide range of academic fields, but has not yet been used in the bio-medical fields, because multiple hazardous raw materials are necessary to synthesize N2O5 in the conventional method. Recently, we have developed a new air atmospheric pressure plasma device, enabling selective production of N2O5 exclusively from sources of air and electricity. This device can also provide the NOx- or ozone-rich gas simply with electric switching for the high- and low-temperature plasma reactors. Using this device, we investigated effects on C. gloeosporioides (strawberry pathogen) sterilization and Qβ phage (RNA virus) inactivation. C. gloeosporioides germination rate was measured as an index of sterilization effect, and it was found that the N2O5 exposure for 60 s significantly decreased the germination rate. Furthermore, mist particles containing Qβ phage were exposed to N2O5, and it was confirmed that the Qβ phage was completely inactivated by N2O5. Because N2O5 in contact with water is well known to generate a reactive intermediate such as nitronium ion, nitronium ion might be a key factor in N2O5 induced virus inactivation. In the presentation, differences in the effects of N2O5 and ozone on virus inactivation will be discussed. |
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