title: Atmospheric pressure plasma: a high-performance tool for the efficient removal of biofilms.
abstract: BACKGROUND
  The medical use of non-thermal physical plasmas is intensively investigated for sterilization and surface modification of biomedical materials. A further promising application is the removal or etching of organic substances, e.g., biofilms, from surfaces, because remnants of biofilms after conventional cleaning procedures are capable to entertain inflammatory processes in the adjacent tissues. In general, contamination of surfaces by micro-organisms is a major source of problems in health care. Especially biofilms are the most common type of microbial growth in the human body and therefore, the complete removal of pathogens is mandatory for the prevention of inflammatory infiltrate. Physical plasmas offer a huge potential to inactivate micro-organisms and to remove organic materials through plasma-generated highly reactive agents.
  
  
  METHODS
  In this study a Candida albicans biofilm, formed on polystyrene (PS) wafers, as a prototypic biofilm was used to verify the etching capability of the atmospheric pressure plasma jet operating with two different process gases (argon and argon/oxygen mixture). The capability of plasma-assisted biofilm removal was assessed by microscopic imaging.
  
  
  RESULTS
  The Candida albicans biofilm, with a thickness of 10 to 20 µm, was removed within 300 s plasma treatment when oxygen was added to the argon gas discharge, whereas argon plasma alone was practically not sufficient in biofilm removal. The impact of plasma etching on biofilms is localized due to the limited presence of reactive plasma species validated by optical emission spectroscopy.
authors.affiliation: Leibniz Institute for Plasma Science and Technology eV, INP Greifswald, Greifswald, Germany. k.fricke@inp-greifswald.de
authors.forename: Katja
authors.initials: K
authors.lastname: Fricke
authors.forename: Ina
authors.initials: I
authors.lastname: Koban
authors.forename: Helena
authors.initials: H
authors.lastname: Tresp
authors.forename: Lukasz
authors.initials: L
authors.lastname: Jablonowski
authors.forename: Karsten
authors.initials: K
authors.lastname: Schröder
authors.forename: Axel
authors.initials: A
authors.lastname: Kramer
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Weltmann
authors.forename: Thomas
authors.initials: T
authors.lastname: von Woedtke
authors.forename: Thomas
authors.initials: T
authors.lastname: Kocher
mesh_terms: D001128:Argon / Q000737:chemistry; D001274:Atmospheric Pressure; D001577:Benzophenones; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007659:Ketones / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D058626:Plasma Gases / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers; D013997:Time Factors
chemical_list: D001577:Benzophenones; D007659:Ketones; D058626:Plasma Gases; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D001128:Argon; D010100:Oxygen