Realization and optimization of an atmospheric pressure plasma source for biomedical application.

Abstract

This thesis represents a biomedical study and research, where we designed and fabricated a device for the generation of cold atmospheric pressure plasma jet, In addition to implementing this device for the cleansing of water samples that are biologically contaminated using bacterial and fungal strains. This device is mainly constituted of two (2) parts:  High voltage generator: it is an electronic circuit that delivers an AC voltage with amplitude that is high enough to easily achieve the excitation required for the gas breakdown and plasma ignition.  A cylindrical shaped plasma reactor with concentric electrodes separated with quartz as dielectric. This reactor when attached to the high voltage generator allows the creation of plasma jets under different working gases. As the practical aim of this thesis is to perform decontamination treatments on aqueous solutions in an efficient and safe manner, we optimized and adapted the plasma device for liquids treatment using a particular setup that allows the regeneration of the plasma jet at the exit of a long flexible plastic tube. In order to determine the optimum parameters that allow the generation of the plasma je in a smooth and stable discharge, we performed first several electrical, physical and electrical characterizations on the plasma jet. In addition to studies about the effect of influencing agents such as the applied voltage and the geometrical parameters of the plasma transportation system on the efficiency of the plasma based treatment and the reactive species generated in the discharge. Results of the experiments performed for the purpose of water decontamination showed that igniting the plasma jet in a controlled gas mixture of argon and oxygen or argon and nitrous oxide lead to the generation of reactive species with antimicrobial potential. When the plasma jet is submerged underwater, these species are delivered in the volume and interact with the bacterial cells leading to their death and inactivation. This study allowed us to define the optimum parameters for proficient water decontamination from biological pollutants.