Regensburg 2022 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 28: Biopolymers, Biomaterials and Bioinspired Functional Materials (joint session CPP/BP)

BP 28.5: Vortrag

Freitag, 9. September 2022, 10:45–11:00, H39

Dissipative Assembly: Controlling Changes of Membrane Topology by Reaction Cycles — •Gregor Ibbeken and Marcus Müller — Institut für Theoretische Physik, Georg-August Universität, Friedrich-Hund-Platz 1, 37075 Göttingen

Coupling a self-assembling system to a reaction cycle, we go beyond equilibrium self-assembly toward systems that dissipate energy and thus exhibit new, unique features of dynamic self- organization. We consider polymers which can switch between a hydrophilic and an amphiphilic state and in the latter self-assemble to form vesicles in aqueous solution. This can occur either by macromolecular or monomeric reactions. In both cases a precursor reacts with a fuel to a product, which itself can decay back to the precursor. We perform particle-based simulations using a soft, coarse grained model for polymers. For the macromolecular reactions we find two drastically different scenarios depending on the fuel volatility: (i) For high fuel volatility, the coupling of inactivated to activated polymers introduces a length scale which dictates the maximal vesicle size and prevents fusion beyond this. This results in an interplay between the architecture- and the reaction-rate-determined length and time scales. (ii) For less volatile fuel, a fuel gradient arises in the system. This results in the compartments moving within the fuel gradient to approach the source. In doing so the moieties gain material over long times which drastically changes the formation mechanism of the vesicles. Finally, we show that the above reaction mechanism can be mimicked by monomeric reactions by the use of multiple, inhomogeneously distributed fuels.