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Laboratoire sur puce pour la détection d'événements cellulaires rares

Marion Valette 1
1 LAAS-MILE - Équipe Micro-Nanofluidique pour les sciences de la vie et de l’environnement
LAAS - Laboratoire d'analyse et d'architecture des systèmes
Abstract : Adipose tissue is a rich source of multipotent stem cells: Adipose Stem Cells (or ASCs). Due to their differentiation capabilities, ASCs became cells of considerable interest for regenerative medicine and are of high interest for type II diabetes diagnosis. Known to migrate and circulate in lymph, the hypothesis of their presence in blood is not excluded but no method exists to prove it. The aim of this study is to develop a lab-on-chip able to isolate ASCs from complex biological samples by using passive and label-free microfluidic sorting methods. These methods involve intrinsic properties of fluids and objects. Yet, ASCs do not have specific physical characteristic. We have demonstrated that their diameter is comprised between 10 and 25 µm: they cannot be distinguished from most of other blood cells. In addition, they do not present specific antigen on their membrane. In order to completely isolate ASCs from other cell types, we propose an original ! approach combining two complementary steps. The first step aims at pre-treating the sample by removing, via hydrodynamic filtration, all the cells with a diameter below 10 µm. With this device, red blood cells, which represent more than 99 % of blood cells, platelets and some leukocytes, have to be removed. This study has demonstrated that the device is able to effectively pre-treat pure blood sample (either from human or from mouse) as it removes more than 99.9 % of red blood cells. It has also been demonstrated that filtration does not lead to cell lysis, which is a promising result for cell viability and the reuse of cells after filtration. The obtained sample contains cells of interest and some remaining hematopoietic cells. The second step aims at refining ASCs isolation by separating them from remaining hematopoietic cells. The method used, called immunological exclusion by cell rolling, is based on antigen-antibody specific reaction. As ASCs do not hav! e specific antigen, leukocytes antigens have been involved. Th! e objective is so to deplete the sample of the remaining leukocytes. This study led to the elaboration of an optimised surface functionalization protocol. Moreover, promising results on cell rolling realised on a surface functionalized with anti-CD45 antibodies were obtained.
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Marion Valette. Laboratoire sur puce pour la détection d'événements cellulaires rares. Micro et nanotechnologies/Microélectronique. Université Toulouse 3 Paul Sabatier (UT3 Paul Sabatier), 2019. Français. ⟨tel-02952733⟩

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