Etude et réalisation d’un jet de plasma pour applications dans le domaine biomédical.

Abstract

An atmospheric pressure plasma jet generation system for biomedical applications consisting of an alternating high voltage generator and a dielectric barrier discharge (DBD) based cylindrical reactor has been realized in the framework of this thesis. In order to determine the optimal parameters for the plasma jet generation by an AC or pulsed excitation and to ensure maximum exploitation of this latter, we carried out a series of electrical and optical measurements. The effects of the variation of the nature of the excitation signal, the applied voltage amplitude and frequency on the geometry of the jet and the reactive species created in air by this plasma jet were studied. First, we used our plasma jet created in using argon at atmospheric pressure for the inactivation of Escherichia coli bacterium spread on a solid surface. We have shown that the inactivation capacity of microorganisms by this plasma jet is directly related to the distance jet source – treated surface as well as to the duration of the treatment. The inactivation rate is more significant as the jet source – sample distance is minimal and the treatment duration is high. Secondly, we treated deionized water contaminated with E-coli bacteria using our plasma jet. We have shown that this treatment allows the creation of ozone, hydrogen peroxide and nitrite. However, the concentrations of these species generated by the plasma jet remain relatively low in order to obtain an effective inactivation of Escherichia coli present in the same amount of deionized water. These investigations have shown that the composition and the dimensions of the created plasma jet can be controlled by means the nature of the excitation signal, its amplitude and / or its frequency. They have also shown that our plasma jet is more effective for the treatment of solid surfaces than for the treatment of aqueous media.