title: Identification of the biologically active liquid chemistry induced by a nonthermal atmospheric pressure plasma jet.
abstract: The mechanism of interaction of cold nonequilibrium plasma jets with mammalian cells in physiologic liquid is reported. The major biological active species produced by an argon RF plasma jet responsible for cell viability reduction are analyzed by experimental results obtained through physical, biological, and chemical diagnostics. This is complemented with chemical kinetics modeling of the plasma source to assess the dominant reactive gas phase species. Different plasma chemistries are obtained by changing the feed gas composition of the cold argon based RF plasma jet from argon, humidified argon (0.27%), to argon/oxygen (1%) and argon/air (1%) at constant power. A minimal consensus physiologic liquid was used, providing isotonic and isohydric conditions and nutrients but is devoid of scavengers or serum constituents. While argon and humidified argon plasma led to the creation of hydrogen peroxide dominated action on the mammalian cells, argon-oxygen and argon-air plasma created a very different biological action and was characterized by trace amounts of hydrogen peroxide only. In particular, for the argon-oxygen (1%), the authors observed a strong negative effect on mammalian cell proliferation and metabolism. This effect was distance dependent and showed a half life time of 30 min in a scavenger free physiologic buffer. Neither catalase and mannitol nor superoxide dismutase could rescue the cell proliferation rate. The strong distance dependency of the effect as well as the low water solubility rules out a major role for ozone and singlet oxygen but suggests a dominant role of atomic oxygen. Experimental results suggest that O reacts with chloride, yielding Cl2(-) or ClO(-). These chlorine species have a limited lifetime under physiologic conditions and therefore show a strong time dependent biological activity. The outcomes are compared with an argon MHz plasma jet (kinpen) to assess the differences between these (at least seemingly) similar plasma sources.
authors.affiliation: Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V., Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany and Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455.
authors.forename: Kristian
authors.initials: K
authors.lastname: Wende
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455.
authors.forename: Paul
authors.initials: P
authors.lastname: Williams
authors.affiliation: Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, Minnesota 55455.
authors.forename: Joe
authors.initials: J
authors.lastname: Dalluge
authors.affiliation: Department of Chemistry, University of Antwerp, Universiteitsplein 1, BE-2610 Antwerp-Wilrijk, Belgium.
authors.forename: Wouter Van
authors.initials: WV
authors.lastname: Gaens
authors.affiliation: College of Veterinary Medicine, University of Minnesota, 1333 Gortner Ave., St. Paul, Minnesota 55108 and Food Science and Technology Department, Alexandria University, Aflaton St., El-Shatby, 21545, Alexandria, Egypt.
authors.forename: Hamada
authors.initials: H
authors.lastname: Aboubakr
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455.
authors.forename: John
authors.initials: J
authors.lastname: Bischof
authors.affiliation: Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V., Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: von Woedtke
authors.affiliation: College of Veterinary Medicine, University of Minnesota, 1333 Gortner Ave., St. Paul, Minnesota 55108.
authors.forename: Sagar M
authors.initials: SM
authors.lastname: Goyal
authors.affiliation: Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V., Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany.
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Weltmann
authors.affiliation: Department of Chemistry, University of Antwerp, Universiteitsplein 1, BE-2610 Antwerp-Wilrijk, Belgium.
authors.forename: Annemie
authors.initials: A
authors.lastname: Bogaerts
authors.affiliation: Center for Innovation Competence Plasmatis, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany and Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V., Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Masur
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, Minnesota 55455.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Bruggeman
mesh_terms: D001128:Argon; D001274:Atmospheric Pressure; D001669:Biochemical Phenomena / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology*; D045604:Extracellular Fluid / Q000737:chemistry / Q000528:radiation effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D058626:Plasma Gases; D017382:Reactive Oxygen Species / Q000032:analysis*
chemical_list: D058626:Plasma Gases; D017382:Reactive Oxygen Species; D001128:Argon; D006861:Hydrogen Peroxide