Reactive hydroxyl radical-driven oral bacterial inactivation by radio frequency atmospheric plasma

Abstract

We demonstrated bacterial (Streptococcus mutans) inactivation by a radio frequency power driven atmospheric pressure plasma torch with H2O2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state center dot OH generation inside the plasma and relative center dot OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing center dot OH generation and reached a maximum 5-log(10) reduction with 0.6% H2O2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H2O2 vapor to the plasma. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3574639]