Développement de dispositifs et de méthodologies pour mesurer des paramètres biophysiques reliés au transport d’eau cellulaire avec la microscopie holographique numérique

Authors: Rioux-Pellerin, Emile
Advisor: Marquet, Pierre; Bélanger, Erik
Abstract: The ability to measure the absolute cell volume is essential to the study of cellular volume regulation and its many different pathways. The permeability of the cell membrane implies that biomolecule inputs and outputs cause transmembrane water transport challenging cell homeostasis. Thenceforth, acell’s volume and a number of other biophysical parameters are modified by changes to the extracellular medium as well as its own activity. Thus, cells have developed a whole series of mechanisms toregulate their volume and maintain their homeostasis. Therefore, cell volume regulation is indicativeof the cell’s state. In the interest of producing reliable volume measurements, it is first advantageous to develop effective tools and methods. For this purpose, quantitative-phase imaging with digital holographic microscopy can provide useful information on the morphology and composition of the cell.The quantitative-phase signal of any object contains two critical parameters for the study of volume regulation, the refractive index and the thickness. The ambiguity of their contribution in the total quantitative phase signal can be resolved by the two-liquid decoupling approach, measuring twice the same sample in two extracellular mediums with different but known refractive indices. The procedure results in two easily solvable phase shift equations with two unknown variables. With the two parameters, the whole-cell volume can be deduced in addition to the dry mass, intracellular concentrationand water content fraction. In order to make better use of the information acquired with the change of fluid, a custom 3d-printed imaging chamber was designed and optimized for stable laminar flow. Forfurther accuracy, grooves were etched on the sample coverslips to monitor in real-time the extracellular refractive index. The combination of both tools expands the utility of the decoupling procedure.It is no longer limited to the initial and final state of the liquid exchange, but can now be used inthe transition period. These novel fluidic essays are used to measure glutamate-induced swelling of primary rat cortical astrocytes
Document Type: Mémoire de maîtrise
Issue Date: 2021
Open Access Date: 19 July 2021
Permalink: http://hdl.handle.net/20.500.11794/69620
Grantor: Université Laval
Collection:Thèses et mémoires

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