Theoretical calculation of the phase behavior of colloidal membranes

Yang, Yasheng; Hagan, Michael F.

doi:10.1103/physreve.84.051402

Cited by 9 publications

(13 citation statements)

References 67 publications

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“…The solid lines identify the the isolated membrane/smectic and nematic/isolated membrane phase boundaries. They are fit by eye to simulation results except for the nematic/isolated membrane boundary in (A) , which is a theoretical prediction 64 . (C) The experimental phase diagram corresponding to (B) using mixtures of fd viruses and PEG/PEO polymers.…”

Section: Figmentioning

confidence: 99%

Self-assembly of 2D membranes from mixtures of hard rods and depleting polymers

et al. 2012

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We combine simulations and experiments to elucidate the molecular forces leading to the assembly of two dimensional membrane-like structures composed of a one rod-length thick monolayer of aligned rods from an immiscible suspension of hard rods and depleting polymers. Computer simulations predict that monolayer membranes are thermodynamically stable above a critical rod aspect ratio and below a critical depletion interaction length scale. Outside of these conditions alternative structures such as stacked smectic columns or nematic droplets are thermodynamically stable. These predictions are confirmed by subsequent experiments using a model system of virus rod-like molecules and non-adsorbing polymer. Our work demonstrates that collective molecular protrusion fluctuations alone are sufficient to stabilize membranes composed of homogenous rods with simple excluded volume interactions.

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Section: Figmentioning

confidence: 99%

Self-assembly of 2D membranes from mixtures of hard rods and depleting polymers

et al. 2012

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“…Computational studies have already provided insightful information about virus NC assembly (20), as well as the interactions between proteins and lipid membranes (21)(22)(23). Previous simulations on budding of nanoscale particles led to important insights but did not consider the effect of GPs (24)(25)(26)(27)(28)(29)(30)(31), although budding directed by GP adsorption or capsid assembly have been the subject of continuum theoretical modeling (32)(33)(34). The formation of clathrin cages during vesicle secretion, a process that bears similarities to viral budding, has also been the subject of modeling studies (35)(36)(37)(38).…”

Section: Introductionmentioning

confidence: 99%

Why Enveloped Viruses Need Cores—The Contribution of a Nucleocapsid Core to Viral Budding

Lázaro

Mukhopadhyay

Hagan

2018

Biophysical Journal

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During the lifecycle of many enveloped viruses, a nucleocapsid core buds through the cell membrane to acquire an outer envelope of lipid membrane and viral glycoproteins. However, the presence of a nucleocapsid core is not required for assembly of infectious particles. To determine the role of the nucleocapsid core, we develop a coarse-grained computational model with which we investigate budding dynamics as a function of glycoprotein and nucleocapsid interactions, as well as budding in the absence of a nucleocapsid. We find that there is a transition between glycoprotein-directed budding and nucleocapsid-directed budding that occurs above a threshold strength of nucleocapsid interactions. The simulations predict that glycoprotein-directed budding leads to significantly increased size polydispersity and particle polymorphism. This polydispersity can be explained by a theoretical model accounting for the competition between bending energy of the membrane and the glycoprotein shell. The simulations also show that the geometry of a budding particle leads to a barrier to subunit diffusion, which can result in a stalled, partially budded state. We present a phase diagram for this and other morphologies of budded particles. Comparison of these structures against experiments could establish bounds on whether budding is directed by glycoprotein or nucleocapsid interactions. Although our model is motivated by alphaviruses, we discuss implications of our results for other enveloped viruses.

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“…The topology of these intermediate structures suppresses the subsequent kinetic step, resulting in the robust formation of two types of line defects whose stability is only limited by the sample lifetime. Theoretical work and computer simulations predict that colloidal membranes are an equilibrium phase that should be observed in diverse suspensions of highly anisotropic monodisperse rods with attractive interactions 14,15 . In the same way that disclination lines are intimately connected and influence the properties of nematic liquid crystals, the defects described here are a ubiquitous feature of colloidal membranes.…”

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Imprintable membranes from incomplete chiral coalescence

et al. 2014

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Coalescence is an essential phenomenon that governs the equilibrium behaviour in a variety of systems from intercellular transport to planetary formation. In this report, we study coalescence pathways of circularly shaped two-dimensional colloidal membranes, which are one rod-length-thick liquid-like monolayers of aligned rods. The chirality of the constituent rods leads to three atypical coalescence pathways that are not found in other simple or complex fluids. In particular, we characterize two pathways that do not proceed to completion but instead produce partially joined membranes connected by line defects-p-wall defects or alternating arrays of twisted bridges and pores. We elucidate the structure and energetics of these defects and ascribe their stability to a geometrical frustration inherently present in chiral colloidal membranes. Furthermore, we induce the coalescence process with optical forces, leading to a robust on-demand method for imprinting networks of channels and pores into colloidal membranes.

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Theoretical calculation of the phase behavior of colloidal membranes

Cited by 9 publications

References 67 publications

Self-assembly of 2D membranes from mixtures of hard rods and depleting polymers

Self-assembly of 2D membranes from mixtures of hard rods and depleting polymers

Why Enveloped Viruses Need Cores—The Contribution of a Nucleocapsid Core to Viral Budding

Imprintable membranes from incomplete chiral coalescence

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