Résumé
The aim of this work is to characterize the flow of biomimetic tissues in microfluidic confinement, as a simplified model for cellular tissue flows observed in complex physiological problems. The prototissues have been conceived by the controlled assembly of giant unillamelar vesicles (GUV) and display tuneable mechanical properties and typical sizes [1]. Aspiration experiments are performed in microfluidic constrictions in order to test the role of GUV-GUV adhesion and aggregate size on the rheological response of the prototissue. In particular, our results show that depending on the aspect ratio between the prototissue and the constriction size the depicted flow behaviour is qualitatively differently. For sizes comparable to the channel constriction, prototissues slightly deform to pass through the constriction and elastically recover their initial shape after passage. For considerably larger sizes instead, a viscoelastic response is observed upon aspiration and almost no shape recovery is obtained after passage of the constriction. This irreversible deformation can be attributed to the rearrangements that take place at the vesicle level, which are dependent, in turn, on the degree of GUV-GUV adhesion [2]. [1] L. Casas-Ferrer, A. Brisson, G. Massiera and L. Casanellas, Design of vesicle prototissues as amodel for cellular tissues. Soft Matter, 17 , 5061 (2021).[2] I. Golovkova, L. Montel, F. Pan, E. Wandersman, A. M. Prevost, T. Bertrand and L-L. Pontani, Adhesion as a trigger of droplet polarization in flowing emulsions, Soft Matter, 17, 3820 (2021).