The Role of VUV Radiation in the Inactivation of Bacteria with an Atmospheric Pressure Plasma Jet

Abstract

Cover: The image shows a modified version of a micro scale He/O 2 atmospheric pressure plasma jet (m-APPJ) source. The so-called X-Jet allows separation of gaseous particles from photons in the effluent downstream of the plasma. The separation is realized in the crossed-channel structure at the nozzle of the jet, where a direct channel (extension of the space between electrodes, where the plasma is located) is crossed by an additional side channel. A helium flow introduced through the side channel of this structure deflects all particles in the plasma effluent into the side channel. The photons, in contrast, are not affected by this additional gas flow and they can propagate undisturbed through the direct channel, which is filled by helium gas. The isolated effect of plasma generated photons or reactive radicals on any substrate placed under the channels can be examined in this way. Moreover, photochemistry reactions initiated by plasma generated photons with the gas mixture in the side channel can also be tested. Further details can be found in the article by S. Benedikt on page 561.

Photons and particles emitted from cold atmospheric-pressure plasma inactivate bacteria and biomolecules independently and synergistically

“…Owing to the feed gas mixture used and the jet being operated in He atmosphere, we would not expect exposure of samples to reactive nitrogen species. We have, however, found additional species stemming from gas impurities, namely protonated water clusters [17]. Atomic oxygen and ozone resulting from photochemistry in the effluent were more than three orders of magnitude lower than plasma-generated atomic oxygen and ozone and below the detection limit of MBMS [17].…”

“…We have, however, found additional species stemming from gas impurities, namely protonated water clusters [17]. Atomic oxygen and ozone resulting from photochemistry in the effluent were more than three orders of magnitude lower than plasma-generated atomic oxygen and ozone and below the detection limit of MBMS [17]. The influence of water in the system is currently subject to further study.…”

“…With 0.6% O 2 admixture in the feed gas, in He atmosphere, we expect the emitted vacuum ultraviolet (VUV) and UV photons to mostly reach the samples [17]. The densities of atomic oxygen, ozone and singlet delta oxygen metastables O 2 (a 1 D g ) that reach the samples after having passed through the jet nozzle and He atmosphere have not yet been determined.…”

Methods of gas purification and effect on the ion composition in an RF atmospheric pressure plasma jet investigated by mass spectrometry

“…The micro atmospheric pressure plasma jet (μ-APPJ) has been in the focus of many studies in the past and is described in great detail in [4,[26][27][28][29][30]. Here, a short description of the recent design will be given together with the operating procedure.…”

Single channel atmospheric pressure transporting plasma and plasma stream demultiplexing: physical characterization and application toE. colibacteria inactivation

“…As shown by Lu, 2008 andGoree, 2006, oxygen-reactive species generated by the plasma jet such as O, and O 3 , can diffuse radially outward and consequently deactivate cells [2,56]. On the other hand, UV photons produced in atmospheric plasma jets propagate preferentially along the plasma column thus they interact only with a part of the target surface located just under the jet [57]. Therefore, judging by the size of the inhibition zone (much larger than the plasma column diameter) one can conclude that the reactive oxygen and nitrogen species (RONS) produced by jet-surrounding air interactions are the major inactivation agents.…”