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SUMMARY:Sascha Hilgenfeldt\, "Tissue modeling: Insight from continuum mech
 anics"
DTSTART:20260730T120000Z
DTEND:20260730T130000Z
DTSTAMP:20260730T120400Z
UID:indico-event-4011@indico.ijs.si
CONTACT:anze.bozic@ijs.si
DESCRIPTION:Two-dimensional vertex models have been used extensively to st
 udy and simulate the mechanical behavior of monolayer tissues\, a simplifi
 ed approach that allows for detailed study of structure and disorder in la
 rge systems. Morphological indicators from the structure are then taken as
  indicators for mechanical behavior and even biological fitness. The most 
 common 2D vertex models use generic elasticity terms whose validity has no
 t been closely scrutinized. Starting from experimental data from MDCK epit
 helial cells\, we question (i) the appropriateness of a 2D model in the li
 ght of severe breaking of mechanical symmetry along the apical-basal axis\
 , and (ii) the accuracy of the functional form of the standard modeling te
 rms. To make progress in both cases\, we describe cells as continuum mater
 ials and use the equations of continuum elasticity to derive correlations 
 between elastic deformation energy and shape parameters. Representing the 
 cortex of a three-dimensional cell as a cylindrical shell\, we find that a
 greement with experimental data requires proper modeling of the 3D deforma
 tion\, i.e.\, the non-uniformity along the apical-basal axis caused primar
 ily by anisotropic actin contractility at the basal side. The relationship
  between elastic energy and perimeter is then found to be non-harmonic\, e
 ven in the limit of vanishing actin content. Therefore\, we construct a 2D
  model modeling cytoplasm and cortex as different materials\, but uniform 
 in the apical-basal direction. Here\, we can analytically compute the defo
 rmation shape and energy for arbitrary outlines of the deformed cell. We f
 ind that the non-harmonic relationship between energy and perimeter persis
 ts\, pointing towards a revised vertex model that retains the simplicity o
 f the standard vertex model\, but is informed by and consistent with conti
 nuum mechanics.\n\nhttps://indico.ijs.si/event/4011/
LOCATION:A/1-106 - Seminarska soba fizike (F5) (Jamova)
URL:https://indico.ijs.si/event/4011/
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