Chiral twist drives raft formation and organization in membranes composed of rod-like particles

Abstract

Lipid rafts are hypothesized to facilitate protein interaction, tension regulation, and trafficking in biological membranes, but the mechanisms responsible for their formation and maintenance are not clear. Insights into many other condensed matter phenomena have come from colloidal systems, whose micron-scale particles mimic basic properties of atoms and molecules but permit dynamic visualization with single-particle resolution. Recently, experiments showed that bidisperse mixtures of filamentous viruses can self-assemble into colloidal monolayers with thermodynamically stable rafts exhibiting chiral structure and repulsive interactions. We quantitatively explain these observations by modeling the membrane particles as chiral liquid crystals. Chiral twist promotes the formation of finite-sized rafts and mediates a repulsion that distributes them evenly throughout the membrane. Although this system is composed of filamentous viruses whose aggregation is entropically driven by dextran depletants instead of phospholipids and cholesterol with prominent electrostatic interactions, colloidal and biological membranes share many of the same physical symmetries. Chiral twist can contribute to the behavior of both systems and may account for certain stereospecific effects observed in molecular membranes.

11 pages, 5 figures

References in corpus (10)

• Self-diffusion of Rod-like Viruses Through Smectic Layer
• Hierarchical organization of chiral rafts in colloidal membranes
• Entropic forces stabilize diverse emergent structures in colloidal membranes
• Interaction of Alamethicin Pores in DMPC Bilayers
• Membrane-mediated repulsion between gramicidin pores
• Theory of self-assembled smectic-A "crenellated disks"
• Theory of microphase separation in bidisperse chiral membranes
• Interaction of chiral rafts in self-assembled colloidal membranes
• Instability of flat disks with respect to the formation of twisted ribbons in smectic-A monolayers
• Flow behavior of colloidal rod-like viruses in the nematic phase

Cited by in corpus (7)

• Equilibrium mechanisms of self-limiting assembly
• Cumulative geometric frustration in physical assemblies
• Spiralling molecular structures and chiral selectivity in model membranes
• Filamentous phages as building blocks for reconfigurable and hierarchical self-assembly
• Conformational switching of chiral colloidal rafts regulates raft-raft attractions and repulsions
• Theory of microphase separation in bidisperse chiral membranes
• Controlling the shape and topology of two-component colloidal membranes