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BP: Fachverband Biologische Physik
BP 15: Tissue Mechanics II
BP 15.4: Talk
Wednesday, March 29, 2023, 11:30–11:45, BAR Schö
Density-dependent active flow transition of biological tissues — •Mathieu Dedenon1,2, Carles Blanch-Mercader3, and Karsten Kruse1,2 — 1Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland — 2Department of Theoretical Physics, University of Geneva, 1211 Geneva, Switzerland — 3Laboratoire Physico-Chimie Curie, Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Paris, France
Biological tissues of elongated cells can spontaneously flow thanks to active stresses, as predicted by 2D generalized hydrodynamics. This effect has been recently confirmed experimentally with confined C2C12 myoblasts.
Under circular confinement, those cells are observed to undergo tissue rotation at confluence. Cells have maximal orientational order at the disc periphery, forming a spiral +1 topological defect. However at a later stage, cell density increases and the tissue ceases rotational motion. This transition is accompanied by a reorientation of cells along the radial direction, transforming the +1 defect into a static aster.
To understand density-dependent spiral-aster transitions, we generalize the previously used 2D polar active fluid description to incorporate a generic passive coupling between cell density and polarity fields. Using symmetry arguments, several energy terms are allowed and we explore systematically how such couplings affect the spontaneous flow transition, under which conditions they promote a spiral-aster transition. This work shows that collective motion is not only driven by tissue active stress but is also sensitive to cell density.