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.
