BPCPPDYSOE21 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 11: Poster A: Single Molecule, Multicellular, Bioimaging, Focus Sessions, etc.

BP 11.34: Poster

Montag, 22. März 2021, 16:30–19:00, BPp

Conditions for thermodynamic stability and critical points in multicomponent mixtures with structured interactions — •Isabella Graf and Benjamin Machta — Yale University, New Haven, CT, USA

Multicomponent mixtures are ubiquitous in biology, ranging from cellular membranes to liquid-like droplets. There is experimental evidence that their phase behavior plays a functional role for signaling and control of biochemical reactions and is under regulation itself. For instance, it has been demonstrated recently that membranes composed of a large variety of lipids are tuned close to a miscibility critical point. Theoretical work has shed light on the phase behavior of idealized systems with many components and random, mutually independent interactions, but there is little understanding of how these results generalize to systems with more structured interactions. To address this open question, we consider a family of multicomponent models with an interaction matrix of variable rank. The matrix is constructed so that each component is characterized by several scalar ``features", each of which conveys an Ising-like interaction between neighboring components and could be interpreted as lipid tail length, headgroup or saturation in the case of membrane lipids. We derive analytical, mean-field conditions for the occurrence of thermodynamic stability and (higher-order) critical points and find that these conditions depend on the cumulants of the principal components of the feature distribution. These results might provide important insights into critical membrane behavior and phase behavior of multicomponent mixtures more generally.