SKM 2023 – scientific programme
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BP: Fachverband Biologische Physik
BP 28: Poster Session II
BP 28.37: Poster
Thursday, March 30, 2023, 18:00–20:00, P2/EG
Micromechanics of spherical cellular aggregates — •Antoine Girot1,2, Marcin Makowski2, Marco Rivetti2, Christian Kreis2, Alexandros Fragkopoulos1,2, Matilda Backholm3, and Oliver Bäumchen1,2 — 1University of Bayreuth, Experimental Physics V, 95447 Bayreuth, Germany — 2Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany — 3Aalto University School of Science, Department of Applied Physics, 02150 Espoo, Finland
Understanding the rich dynamics of biophysical processes, such as pathogenic tissue development and morphogenesis, requires a proper mechanical characterization of multicellular aggregates. Spherical aggregates often serve as model systems, yet, they cannot be readily characterized with conventional techniques that are optimized for single cells. In this presentation, we report on Volvox globator, a natural cellular aggregate that is composed of hundreds of bi-flagellated cells forming a spherical monolayer filled with mucilage. We employ in vivo micropipette force measurements combined with optical detection to simultaneously measure the force response and the deformation of this living aggregate. We show that the micromechanics of Volvox can be described by a model coupling elasticity and viscosity, which allows to extract the mechanical properties. We find that the viscous component exhibits a shear-thinning behavior, that can be properly described by implementing a power-law fluid model, while the elasticity of the aggregate depends on its size.