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Spectroscopie diélectrique hyperfréquence de cellules individualisées sous électroporation

Abstract : Electroporation is a physical process that consists in applying electric field pulses to transiently or permanently permeabilize the plasma membrane. This phenomenon is of great interest in the clinical field as well as in the industry because of its various applications, in particular electrochemotherapy which combines electrical pulses with the administration of a cytotoxic molecule in the treatment of tumors. The evaluation of this phenomenon is raditionally carried out using optical and biochemical methods (microscopy, flow cytometry, biochemical test). They are very effective but require the use of a wide range of fluorochromes and markers, which can be laborious and costly to implement, while being invasive to the cells. In recent years, the development of new biophysical tools for the study of electroporation has taken place, such as dielectrophoresis and impedance spectroscopy (low frequency). In addition to the ease of implementation, these methods are of interest in the study of membrane modifications of the cell. Hence the advantage of operating beyond the GHz, in the range of microwaves, for which the cytoplasmic membrane becomes transparent and the intracellular content is exposed. The extraction of the relative permittivity as a result of the electromagnetic field / biological cell interaction then reflects the cell state. This technique, microwave dielectric spectroscopy, is a relevant method for analyzing the effects of electroporation on cell viability. Moreover, it does not require any use of the exogenous molecules (non-invasive) and the measurements are directly carried out in the culture medium of the cells. Two objectives were defined during this thesis whose work is located at the interface between three scientific fields: cellular biology, microwave electronics and micro-technologies. The first objective concerns the transposition of conventional electroporation to the micrometric scale, which has shown an efficiency as efficient as the first. The second part of the work concerns the study by HighFrequency dielectric spectroscopy of cells subjected to different electrical treatments (combined or not with a cytotoxic molecule). This work presents a statistical power and shows a very good correlation (R2> 0.94) with standard techniques used in biology, which biologically validates the HF analysis method in the context of electroporation. This work also shows that microwave dielectric spectroscopy proves to be a powerful technique capable of revealing cell viability following chemical and / or electrical treatment. They open the way to 'non-invasive' analysis by hyper-frequency dielectric spectroscopy of electroporated cells in situ.
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Submitted on : Tuesday, February 20, 2018 - 11:58:05 AM
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  • HAL Id : tel-01499406, version 2

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Amar Tamra. Spectroscopie diélectrique hyperfréquence de cellules individualisées sous électroporation. Ingénierie biomédicale. Université Paul Sabatier - Toulouse III, 2017. Français. ⟨NNT : 2017TOU30011⟩. ⟨tel-01499406v2⟩

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