Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 27: Statistical Physics of Biological Systems 2 (joint session BP/DY)
BP 27.4: Vortrag
Donnerstag, 8. September 2022, 15:45–16:00, H16
Biological tissues as living amorphous solids — •Ali Tahaei and Marko Popović — Max Planck Institute for Physics of Complex Systems, Dresden
Biological tissues are often described as viscoelastic fluids on long time-scales. However, on shorter times-scales, tissues can behave as amorphous solids, such as clay, changing shape only when exposed to a shear stress above the material yield stress Σc. Amorphous solids near Σc display critical behaviour with a diverging correlation length-scale characterising dynamics of plastic activity. Here, we ask how would this critical behaviour be affected by active processes present in biological tissues, such as cell divisions.
In order to model yielding of biological tissues we employ the mesoscopic elasto-plastic model, commonly used to describe yielding of amorphous solids. Here, we extend the classical elasto-plastic model by introducing cell divisions as an additional source of plastic activity. We find that cell divisions strongly fluidise the solid phase of the system at stresses lower than Σc, consistent with literature. Furthermore, we find that critical behaviour is strongly suppressed, leading to localised dynamics of plastic activity nucleated by cell divisions. Finally, in our model we can describe how well is the cell division orientation aligned with local shear stress. We find that low alignment strength leads to less mechanically stable tissues where, consequently, most of the plastic flow arises from cell rearrangements, and vice versa.