2011/05/31 by Simon Schneider, Schneider, Simon, Jan-Wilm Lackmann +12 · 1 citation
Medicine · Physics and Astronomy · #Dust and Plasma Wave Phenomena #FOS: Physical sciences #Plasma Applications and Diagnostics #Plasma Physics (physics.plasm-ph) #physics.plasm-ph
paper · pdf · doi:10.48550/arxiv.1105.6260
21 pages, 6 figures, submitted to Plasma Processes and Polymers, Special Issue: Sterilization
arxiv created 2011/05/31 · openalex publication_date 2011/05/31 · arxiv updated 2011/06/01 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
A modified version of a micro scale atmospheric pressure plasma jet (μ-APPJ) source, so-called X-Jet, is used to study the role of plasma generated VUV photons in the inactivation of E. coli bacteria. The plasma is operated in He gas or a He/O2 mixture and the X-Jet modification of the jet geometry allows effective separation of heavy reactive particles (such as O atoms or ozone molecules) from the plasma-generated photons. The measurements of the evolution of zone of inhibitions formed in monolayers of vegetative E. coli bacteria, of VUV emission intensity and of positive ion spectra show that photochemistry in the gas phase followed by photochemistry products impacting on bacteria can result in bacterial inactivation. Interestingly, this process is more effective than direct inactivation by VUV radiation damage. Mainly protonated water cluster ions are detected by mass spectrometry indicating that water impurity has to be carefully considered. The measurements indicate that the combination of the presence of water cluster ions and O2 molecules at the surface leads to the strongest effect. Additionally, it seem that the interaction of VUV photons with effluent of He/O2 plasma leads to enhanced formation of O3, which is not the case when only O2 molecules and gas impurities at room temperature interacts with plasma generated VUV photons.