Berlin 2024 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

BP: Fachverband Biologische Physik

BP 33: Focus session: Physics of organoids

BP 33.4: Talk

Thursday, March 21, 2024, 16:00–16:15, H 1028

Morphological instability at topological defects in spherical epithelial shells — •Oliver M. Drozdowski and Ulrich S. Schwarz — Institute for Theoretical Physics and BioQuant, Heidelberg University, 69120 Heidelberg, Germany

Spherical epithelial shells like cysts or intestinal organoids are model systems for developmental biology and have large potential for biomedical applications. They also lead to highly interesting physics questions: due to Euler's polyhedron theorem, they must contain at least 12 topological defects in the network of neighbor relations, similar to viral capsids. Topological defects have mainly been studied in a hydrodynamic context. Here we study them in the elastic context of spherical epithelial shells. We start from a three-dimensional vertex model and perform a rigorous coarse-graining procedure to a continuum model. We predict stretching and bending moduli in excellent agreement with computer simulations of the vertex model. For large spherical shells we find a generic morphological instability to an icosahedral shape at topological defects, at a length scale similar to budding events in organoids. This instability can be explained by our continuum theory and might be used by organoids to change shape during development.

Keywords: Organoids; Vertex Model; Continuum Mechanics; Coarse-Graining