Résumé
The aim of this work is to provide a multiscale rheological description of biomimetic synthetic tissues in microfluidic confinement, as a simplified model for the flow of cellular tissues observed in complex physiological problems such as in embryogenesis or tumour metastasis. Providing a complete description across length scales which relates the properties of individual cells to the rheological behavior of complex 3D-tissues remains an open challenge. The development of biomimetic model tissues with simplified biochemical complexity, but capable of reproducing essential mechanical features of living tissues, can help in achieving this major goal. We designed a simple microfluidic device that allowed us to achieve simultaneously the conception of biomimetic prototissues and their in-situ multiscale rheological characterization. By the controlled assembly of Giant Unilamellar Vesicles (GUVs) inside a microfluidic trap we were capable of synthesizing model prototissues with tailored mechanical properties (size, shape and GUV-GUV adhesion). Rheological properties of prototissues were probed in a “pipette-aspiration” inspired microfluidic device (an example is shown in the figure), under controlled pressure conditions. We reported a viscoelastic response, which was well captured by a generalized Kelvin-Voigt fluid model. The prototissue rheology was complemented with an analysis at the scale of individual vesicles based on segmentation methods, which allowed us to quantify the deformation of vesicles under flow and the reorganizations taking place between vesicles within the prototissue.