Effects of Metastable Species in Helium and Argon Atmospheric Pressure Plasma Jets (APPJs) on Inactivation of Periodontopathogenic Bacteria
2016.06.13 10:57
연도 | 2016 |
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저널명 | Journal of the Korean Physical Society |
쪽 |
Abstract
The helium and argon have been widely used as discharge gases in atmospheric pressure plasma
jets (APPJs) for bacteria inactivation. The APPJs show apparent different in bullet propagation
speed and bacteria inactivation rate apparently vary with discharge gas species. This work shows
that these two distinctive features of APPJs can be linked through one factor, the metastable
energy level. The effects of helium and argon metastable species on APPJ discharge mechanism
for reactive oxygen nitrogen species (RONS) generation in APPJs are investigated by experiments
and numerical estimation. The discharge mechanism is investigated by using the bullet velocity
from the electric field which is obtained with laser induced fluorescence (LIF) measurement. The
measured electric field also applied on the estimation of RONS generation, as electron energy source
term in numerical particle reaction. The estimated RONS number is verified by comparing NO and
OH densities to the inactivation rate of periodontitis bacteria. The characteristic time for bacteria
inactivation of the helium-APPJ was found to be 1.63 min., which is significantly less than that of
the argon-APPJ, 12.1 min. In argon-APPJ, the argon metastable preserve the energy due to the
lack of the Penning ionization. Thus the surface temperature increase is significantly higher than
helium-APPJ case. It implies that the metastable energy plays important role in both of APPJ
bullet propagation and bacteria inactivation mechanism.
doi:10.3938/jkps.68.1176
https://link.springer.com/article/10.3938/jkps.68.1176