Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 7: Poster Session I

BP 7.27: Poster

Montag, 9. März 2026, 15:00–17:00, P5

Passive vs active shells: from spectrin to actin cortex — •Tim Kutz¹, Bart Vos¹, Bart Jan Ravoo², Andreas Janshoff³, and Timo Betz¹ — ¹Third Institute of Physics, Georg August Universität Göttingen, Göttingen, Germany — ²Institute of Physical Chemistry, Georg August Universität Göttingen, Göttingen, Germany — ³Organic Chemistry Institute and Center for Soft Nanoscience, University of Münster

The viscoelastic and tensile properties of the cell surface are key regulators of processes such as migration, division, and shape control, yet the respective roles of membrane and cortex remain only partially understood. Here, we use a combined experimental approach integrating atomic force microscopy (AFM) and micropipette (MPA) aspiration to dissect surface mechanics in two paradigmatic systems: red blood cells (RBCs) and Xenopus tadpole cells (XTCs). RBCs provide a membrane-dominated reference state with a passive spectrin network, while XTCs feature an active actomyosin cortex coupled to the plasma membrane. AFM-based tether pulling and creep compliance measurements yield local effective tension and viscoelastic response, whereas MPA reports global surface tension and large-scale deformation behaviour. From the combined data, we identify clear differences in relaxation behavior and tension build-up between RBCs and XTCs, reflecting the presence of active contractile elements in the cortex. Our results demonstrate how multi-modal micromechanical probing can disentangle membrane- versus cortex-dominated contributions to cell surface tension.

Keywords: surface tension; hRBC; XTC; AFM; micropipette aspiration