Dresden 2017 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 65: Complex Fluids and Soft Matter (organized by DY)
CPP 65.8: Talk
Friday, March 24, 2017, 11:45–12:00, HÜL 186
How to regulate the position of a droplet in a heterogeneous liquid environment? — •Samuel Krüger1,2, Christoph A. Weber4, Jens-Uwe Sommer2,3, and Frank Jülicher1 — 1Max Planck Institute for the Physics of Complex Systems — 2Leibniz Institute of Polymer Research Dresden e.V. — 3Technische Universität Dresden, Institute of Theoretical Physics, Dresden, Germany — 4Harvard University, Division of Engineering and Applied Sciences, Cambridge, USA
Cells contain organelles that are not separated from the cytoplasm by a membrane. An example are liquid-like P granules in the C. elegans embryo. P Granules consist of RNA and proteins that are segregated from the cytoplasm. During asymmetric cell division, P granules are segregated to one side of the cell and distributed to only one daughter cell. This segregation is guided by the spatial concentration gradient of the protein Mex-5. Motivated by this system, we study the general question of how droplets are positioned in a concentration gradient of a regulator molecule that influences phase separation. We consider a ternary system and study the simplified case, where an external potential establishes the regulator gradient. A mean field Flory-Huggins model reveals a first order phase transition between the droplet position at high and low regulator concentration. We discuss this result in comparison to Monte Carlo simulations. Simulations reveal signatures of the mean field phase transition and give insight into the free energy landscape of the system in the presence of fluctuations.