Dresden 2020 – scientific programme

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BP: Fachverband Biologische Physik

BP 28: Statistical Physics of Biological Systems II (joint session BP/DY)

BP 28.3: Talk

Wednesday, March 18, 2020, 15:45–16:00, ZEU 250

Plasticity in vertex model of epithelial tissues — •Marko Popović, Valentin Druelle, and Matthieu Wyart — Institue of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

In order to properly develop and function living organisms are required to change and maintain shape. This can be achieved by reshaping a liquid-like tissue and then changing its material properties to stabilize the final shape. Alternatively, if the tissue is plastic it will respond elastically to stresses below some critical value but higher values of stress will produce a plastic flow leading to a permanent plastic shape change, allowing it to retain the memory of stresses that have acted on it. Plasticity is exhibited by a wide class of amorphous solids such as: colloidal gels, emulsions and foams where it corresponds to a yielding transition. Are there features of yielding transition, such as strong dependence on system preparation and collective particle rearrangements leading to non-linear rheology, that are relevant during biological morphogenesis? Motivated by similarities of disordered tissues and amorphous solids we study plastic properties of vertex model of epithelial tissues, where mechanical properties of individual cells are prescribed and emerging tissue mechanics is obtained from their collective behaviour. We study mechanical properties of elementary plastic event in epithelial tissues, a so called T1 transition, in which two pairs of cells exchange neighborship. We demonstrate that interactions between T1 transitions are analogous to those of particle rearrangements in amorphous solids and that vertex model belongs to the same class of universality.