Membrane-mediated aggregation of anisotropically curved nanoparticles

Abstract

Using systematic numerical simulations, we study the self-assembly of elongated curved nanoparticles on lipid vesicles. Our simulations are based on molecular dynamics of a coarse-grained implicit-solvent model of self-assembled lipid membranes with a Langevin thermostat. Here we consider only the case wherein the nanoparticle-nanoparticle interaction is repulsive, only the concave surface of the nanoparticle interacts attractively with the lipid head groups and only the outer surface of the vesicle is exposed to the nanoparticles. Upon their adhesion on the vesicle, the curved nanoparticles generate local curvature on the membrane. The resulting nanoparticle-generated membrane curvature leads in turn to nanoparticle self-assembly into two main types of aggregates corresponding to chain aggregates at low adhesion strengths and aster aggregates at high adhesion strength. The chain-like aggregates are due to the fact that at low values of adhesion strength, the nanoparticles prefer to lie parallel to each other. As the adhesion strength is increased, a splay angle between the nanoparticles is induced with a magnitude that increases with increasing adhesion strength. The origin of the splay angles between the nanoparticles is shown to be saddle-like membrane deformations induced by a tilt of the lipids around the nanoparticles. This phenomenon of membrane mediated self-assembly of anisotropically curved nanoparticles is explored for systems with varying nanoparticle number densities, adhesion strength, and nanoparticle intrinsic curvature.

Interactions of rod-like particles on responsive elastic sheets

“…38 At higher densities of adsorbed virus particles, also branched arrangements of viruses were observed. 38 Also, interesting findings of computer simulations appeared recently regarding the assembly of curved cylindrical particles on a model lipid vesicle via side-toside versus tip-to-tip contacts, 67 also motivating the current research. Such in vitro virus-vesicle systems might shed light onto the properties of interactions of elongated viruses-including dangerous Ebola and Marburg viruses 68,69 -with the membranes of living cells.…”

“…In particular, membrane-mediated aggregation of anisotropically curved banana-like Janus nanoparticles on large lipid vesicles was recently studied by simulations. 67 A wide range of particlemembrane adhesion, intrinsic particle curvature and particle density on the membrane was studied. 67 The membrane curvature due to anisotropic particle-membrane binding yields two main types of self-assembled structured: chain-like aggregates at weak bindings and asters at high adhesion strengths.…”

“…67 A wide range of particlemembrane adhesion, intrinsic particle curvature and particle density on the membrane was studied. 67 The membrane curvature due to anisotropic particle-membrane binding yields two main types of self-assembled structured: chain-like aggregates at weak bindings and asters at high adhesion strengths. 67 In the former, the nanoparticles prefer to stay parallel.…”

“…67 The membrane curvature due to anisotropic particle-membrane binding yields two main types of self-assembled structured: chain-like aggregates at weak bindings and asters at high adhesion strengths. 67 In the former, the nanoparticles prefer to stay parallel. In contrast, for strong particle-vesicle attraction strengths some three-armed stars are formed, due to saddle-like membrane deformations around them.…”

Membrane morphologies induced by mixtures of arc-shaped particles with opposite curvature

“…In molecular dynamics (MD) simulations with a coarse-grained molecular model of N-BAR domains proteins on DLPC lipid vesicles, in contrast, a tip-to-tip alignment of proteins has been observed 48,67 , which may be affected by the direct, coarse-grained protein-protein interactions of the model. A tip-to-tip alignment has also been reported for MD simulations with a coarse-grained model of I-BAR domains 53 and for coarse-grained MD simulations of arc-shaped nanoaparticles on lipid vesicles at large adhesion energies of the nanoparticles 51 . At these large adhesion energies, the nanoparticles are partially wrapped by the membrane, which leads to saddle-like membrane curvature around nanoparticles that may cause side-to-side repulsion.…”