Dresden 2020 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 10: Poster III

BP 10.25: Poster

Montag, 16. März 2020, 17:30–19:30, P2/3OG

stress stiffening of suspended cells — •elham mirzahossein1, sebastian muller2, stephan geckle2, and ben fabry11University of Erlangen-Nuremberg — 2Department of Physics, university of Bayreuth

The stiffness of adherent cells has been shown to increase linearly with contractile (pre-) stress of the cytoskeleton and externally applied stress. Previous studies of suspended cells that are forced through small microfluidic constrictions reported the same stress stiffening behavior as in adherent cells, however, the mechanical loading of cells in a microfluidic constriction is complex. to overcome these limitations, here we measure the deformations of adherent suspended cells in response to simple shear stress. nih-3t3 fibroblasts are mixed in shear-thinning 2% alginate solution and are pressed at 1-3 bar through a 200 × 200 µ m and 5 cm long microfluidic channel. the shear stress is zero in the channel center and increases linearly towards the walls. as a consequence, cells appear round in the channel center and become elongated towards the walls, with aspect ratios of up to 3. the Taylor strain,є , of the cells versus fluid shear stress, σ, shows a non-linear relationship. This relationship is well described by a differential cell stiffness of the form E = ∂ σ/∂ є=E0 +α · σ. Cell stiffness is E0 = 100 Pa at low shear stress and linearly increases with shear stress with a factor α=8. at the highest shear stress value of 300 Pa that we apply in our study, differential cells stiffness increases to 1700 pa on average. thus, our measurements of suspended cells show a pronounced stress stiffening that is similar to the behavior found in adherent cells.

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