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Interaction colloïdes - cellules : étude de l'adhésion spécifique

Abstract : This work, at the interface between physics, chemistry and biology, deals with the interaction between colloids (such as virus or vectors) and living cells (HeLa cells). We try to describe the binding of functionnalized lipidic particles targeting specific cell membrane receptors, both through a global statistical approach based on kinetic measurements and through a local approach based on force measurement. Because of its therapeutic relevance (tumours targeting, retrograde transport), the Shiga toxin B subunit was mainly used in order to prepare colloids targeting the Gb3 receptors (chapter 1). On the one hand, kinetic measurements of the adhesion of Shiga toxin grafted colloids could be performed and compared to different theoretical models, allowing us to propose different mechanisms of particles binding, Inspired by polymerization mechanismms, we particurlarly focused on a moded based on the succesive recruitment of receptors (2). Moreover, we studied the effect of different modifications of the colloid surface (polymers, nature and density of ligands) on adhesion. This study allowed us to quantify the repulsive effect of polymers on particles binding and to suggest a microscopic interpretation involving the glycocalyx (3and 4). On the other hand, by carrying out micromanipulation experiments (Biomembrane Force Probe technique), we were able to measure locally the force of the link between a single colloid and a single cell. This experiment revealed a quantification of forces, suggesting the successive recruitment of receptors (5). Finally, we just started to examine the entry and the intracellular fate of these particles into the cells (6). This work underlines how quantitative physical measurements can enable to propose a microscopic description of biological mechanisms.
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https://tel.archives-ouvertes.fr/tel-00012076
Contributor : Nadine Laffargue <>
Submitted on : Monday, April 3, 2006 - 2:37:05 PM
Last modification on : Thursday, January 11, 2018 - 6:14:59 AM
Long-term archiving on: : Saturday, April 3, 2010 - 11:06:19 PM

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  • HAL Id : tel-00012076, version 1

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Cécile Poirier. Interaction colloïdes - cellules : étude de l'adhésion spécifique. Biologie cellulaire. Université Sciences et Technologies - Bordeaux I, 2005. Français. ⟨tel-00012076⟩

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