Long-term antibacterial efficacy of air plasma-activated water

Matthew J. Traylor, Matthew J. Pavlovich, Sharmin Karim, Pritha Hait, Yukinori Sakiyama, Douglas S. Clark, David B. Graves

Research output: Contribution to journalArticlepeer-review

415 Scopus citations


Indirect air dielectric barrier discharge in close proximity to water creates an acidified, nitrogen-oxide containing solution known as plasma-activated water (PAW), which remains antibacterial for several days. Suspensions of E. coli were exposed to PAW for either 15 min or 3 h over a 7-day period after PAW generation. Both exposure times yielded initial antibacterial activity corresponding to a ∼5-log reduction in cell viability, which decreased at differing rates over 7 days to negligible activity and a 2.4-log reduction for 15 min and 3 h exposures, respectively. The solution remained at pH ∼2.7 for this period and initially included hydrogen peroxide, nitrate and nitrite anions. The solution composition varied significantly over this time, with hydrogen peroxide and nitrite diminishing within a few days, during which the antibacterial efficacy of 15 min exposures decreased significantly, while that of 3 h exposures produced a 5-log reduction or more. These results highlight the complexity of PAW solutions where multiple chemical components exert varying biological effects on differing time scales.

Original languageEnglish (US)
Article number472001
JournalJournal of Physics D: Applied Physics
Issue number47
StatePublished - Nov 30 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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