Experimental Study of ICP in O2:N2:H2 Mixtures for Sterilization of Bacterial Spores

Non-equilibrium discharges in molecular gases and their mixtures are extensively studied due to their applicability in different domain such as of surface treatment, cleaning and functionalisation as well as for sterilisation and decontamination. This is mainly thanks to the fact that low-pressure discharges are potent sources of number of active particles as well as intense UV radiation interacting with treated surfaces. However, the total effectiveness of plasma action is often a result of the synergetic effect of different processes taking part during plasma processing. This is also the case of sterilisation of bacterial spores. In this particular application total sterilisation effectiveness depends on the intensity of UV radiation that destroys the DNA of the spores, on the densities of oxygen radicals that erode their outer layer and/or remove material shielding DNA from UV radiation and finally on the amount of H atoms that have been found to accelerate deactivation of bacterial endotoxins. In order to optimise sterilisation process it is therefore desired to maximise contributions of three different quantities – UV radiation together with O and H atoms densities. The aim of this contribution is to demonstrate that this objective can be reached employing a ternary mixture composed of O2, N2 and H2. ICP discharge (applied RF power 500 W, pressure 100 mTorr and gas flow 10 sccm) has been systematically studied by means of optical emission spectroscopy. The dependencies of UV intensity as well as intensities of O and H atomic lines have been determined as a function of the initial ratios of used gases in the discharge mixture. The main objective of this contribution is to summarised obtained results.

KYLIAN Ondrej;  COLPO Pascal;  ROSSI Francois; 

2006-10-31

INST PHYSICS ACAD SCI CZECH REPUBLIC

JRC34586

https://publications.jrc.ec.europa.eu/repository/handle/JRC34586,