Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 3: Cell Mechanics 1
BP 3.2: Vortrag
Montag, 5. September 2022, 10:00–10:15, H15
Viscoelasticity of spherical cellular aggregates — •Antoine Girot1,2, Marcin Makowski1, Marco Rivetti1, Christian Kreis1,3, Alexandros Fragkopoulos1,2, and Oliver Bäumchen1,2 — 1Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany — 2University of Bayreuth, Experimental Physics V, 95447 Bayreuth, Germany — 3Department of Physical and Environmental Sciences, University of Toronto, ON Toronto, Canada
Understanding the complexity of many biophysical processes such as the dynamics of biological tissues requires a proper mechanical characterization of multicellular aggregates. Current experimental techniques, however, are typically limited to systems that are not larger than an individual cell. We employ in vivo micropipette force measurements combined with optical detection to precisely measure the force response and the deformation of living organisms simultaneously. In this presentation, we use this approach to investigate the mechanical behaviour of Volvox globator, a multicellular aggregate composed of thousands bi-flagellated cells forming a spherical monolayer filled with mucilage. Volvox is considered a model system, e.g. to study the evolution from single cells to multicellular life. We show that a model that couples elastic and viscous components is in excellent agreement with the mechanical response of Volvox and therefore can be used to extract the viscoelastic properties. We find that the viscous component is rate-dependent and exhibits a shear-thinning behaviour, while the elasticity of the cellular monolayer depends on the size of the colony.