Regensburg 2019 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 47: Statistical physics of biological systems II (joint session BP/DY)

DY 47.7: Hauptvortrag

Donnerstag, 4. April 2019, 16:30–17:00, H11

Spontaneous buckling of active matter — •Karsten Kruse — NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, 1211 Geneva, Switzerland

Active matter in living systems is often organized in the form of quasi two-dimensional sheets. Examples are the actin cortex of animal cells or epithelial cell monolayers in organisms. In many processes, these sheets fold, for instance, during cell division or gastrulation, which is the developmental process of inward folding of a single-cell layered sphere in early embryogenesis. The molecular players and signaling cascades involved in these processes have been studied in detail. In contrast, the underlying mechanics remains poorly characterized. This is in large part due to technical difficulties in measuring the material properties of these systems as well as the forces acting on them. Theoretical analysis can shed light on the mechanics governing the spontaneous buckling of active matter as I will illustrate by two model systems: One system consists of an initially homogenous actomyosin sheet reconstituted in vitro that can buckle spontaneously into states of positive and negative Gaussian curvature upon contraction. The other example is provided by a cell monolayer growing on the inside of an elastic sphere. It buckles spontaneously as cells continue to proliferate beyond the state when the whole inner surface of the sphere is covered with cells. In both cases, theoretical analysis allows to extract mechanical properties of the active materials that are difficult to assess otherwise.