title: Studies of air, water, and ethanol vapor atmospheric pressure plasmas for antimicrobial applications.
abstract: The generation of air-based plasmas under atmospheric plasma conditions was studied to assess their antimicrobial efficacy against commonly found pathogenic bacteria. The mixture of initial gases supplied to the plasma was found to be critical for the formation of bactericidal actives. The optimal gas ratio for bactericidal effect was determined to be 99% nitrogen and 1% oxygen, which led to a 99.999% reduction of a pathogenic strain of Escherichia coli on stainless steel surfaces. The experimental substrate, soil load on the substrate, flow rate of the gases, and addition of ethanol vapor all were found to affect antimicrobial efficacy of studied plasmas. Optical emission spectroscopy was used to identify the species that were present in the plasma bulk phase for multiple concentrations of nitrogen and oxygen ratios. The collected spectra indicate a unique series of bands present in the ultraviolet region of the electromagnetic spectrum that can be attributed to nitric oxide species known to be highly antimicrobial. This intense spectral profile dramatically changes as the concentration of nitrogen decreases.
authors: EP Technologies LLC, Akron, Ohio 44311.
authors: James R
authors: JR
authors: Ferrell
authors: EP Technologies LLC, Akron, Ohio 44311.
authors: Erinn R
authors: ER
authors: Bogovich
authors: EP Technologies LLC, Akron, Ohio 44311.
authors: Nicholas R
authors: NR
authors: Lee
authors: EP Technologies LLC, Akron, Ohio 44311.
authors: Robert L
authors: RL
authors: Gray
authors: EP Technologies LLC, Akron, Ohio 44311.
authors: Daphne D
authors: DD
authors: Pappas
mesh_terms: D000388:Air; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001274:Atmospheric Pressure; D004783:Environmental Microbiology; D004926:Escherichia coli / Q000187:drug effects* / Q000502:physiology; D000431:Ethanol / Q000494:pharmacology*; D050296:Microbial Viability / Q000187:drug effects; D058626:Plasma Gases / Q000737:chemistry / Q000494:pharmacology*; D013057:Spectrum Analysis; D014867:Water / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D058626:Plasma Gases; D014867:Water; D000431:Ethanol