Wrapping of ellipsoidal nano-particles by fluid membranes

Abstract

Membrane budding and wrapping of particles, such as viruses and nano-particles, play a key role in intracellular transport and have been studied for a variety of biological and soft matter systems. We study nano-particle wrapping by numerical minimization of bending, surface tension, and adhesion energies. We calculate deformation and adhesion energies as a function of membrane elastic parameters and adhesion strength to obtain wrapping diagrams. We predict unwrapped, partially-wrapped, and completely-wrapped states for prolate and oblate ellipsoids for various aspect ratios and particle sizes. In contrast to spherical particles, where partially-wrapped states exist only for finite surface tensions, partially-wrapped states for ellipsoids occur already for tensionless membranes. In addition, the partially-wrapped states are long-lived, because of an increased energy cost for wrapping of the highly-curved tips. Our results suggest a lower uptake rate of ellipsoidal particles by cells and thereby a higher virulence of tubular viruses compared with icosahedral viruses, as well as co-operative budding of ellipsoidal particles on membranes.Comment: 10 pages, 11 figure

Partial wrapping and spontaneous endocytosis of spherical nanoparticles by tensionless lipid membranes

“…[19][20][21][22][23][24][25][26][27] In particular, Deserno et al 19,20 used the Helfrich Hamiltonian 28 with contact adhesion interaction between the NP and the bilayer to show that in the case of a bilayer under tension, the NP is either unbound, partially wrapped, or completely wrapped by the bilayer. However, the NP is either unbound or fully wrapped by a tensionless bilayer.…”

A Universal Law for Cell Uptake of One-Dimensional Nanomaterials

“…Recent studies showed that short rigid adhesive nanorods including ellipsoidal nanoparticles with small aspect ratios orient their longer axes parallel to the membrane first and remain in that configuration until about a half of the particle surface area is wrapped, and then undergo a configurational transition by realigning their longer axes perpendicular to the membrane during further wrapped. 38,39,42,43 After the transition moment, a short nanorod remaining parallel to the membrane with both highly curved ends covered by the membrane would cost more membrane bending energy than that the perpendicular configuration in which only one end needs to be covered by the membrane. Here, the membrane bending energy difference results in nanoparticle reorientation.…”

Theory, simulations and the design of functionalized nanoparticles for biomedical applications: A Soft Matter Perspective

“…Different aspects of receptor-mediated endocytosis have been intensively studied using both theory, 11,[19][20][21][22][23][24][25] and different types of simulations 10,[26][27][28][29][30][31][32][33][34][35][36][37] with coarse-grained models, often combining the two. 10,27 A pioneering work on this problem is that of Gao et al, 19 who proposed a theoretical model to address the size dependence of this process, drawing from previous work on the growth of membrane adhesion patches.…”

“…(Adapted from ref. 35 with permission from The Royal Society of Chemistry.) Such surface allows to numerically discretise the continuum description defined by the Canhan-Helfrich Hamiltonian.…”