6 research outputs found
Polyhedral vesicles
Polyhedral vesicles with a large bending modulus of the membrane such as the
gel phase lipid membrane were studied using a Brownian dynamics simulation. The
vesicles exhibit various polyhedral morphologies such as tetrahedron and cube
shapes. We clarified two types of line defects on the edges of the polyhedrons:
cracks of both monolayers at the spontaneous curvature of monolayer , and a crack of the inner monolayer at . Around the
latter defect, the inner monolayer curves positively. Our results suggested
that the polyhedral morphology is controlled by .Comment: 4 pages, 5 figure
A lattice model for the kinetics of rupture of fluid bilayer membranes
We have constructed a model for the kinetics of rupture of membranes under
tension, applying physical principles relevant to lipid bilayers held together
by hydrophobic interactions. The membrane is characterized by the bulk
compressibility (for expansion), the thickness of the hydrophobic part of the
bilayer, the hydrophobicity and a parameter characterizing the tail rigidity of
the lipids. The model is a lattice model which incorporates strain relaxation,
and considers the nucleation of pores at constant area, constant temperature,
and constant particle number. The particle number is conserved by allowing
multiple occupancy of the sites. An equilibrium ``phase diagram'' is
constructed as a function of temperature and strain with the total pore surface
and distribution as the order parameters. A first order rupture line is found
with increasing tension, and a continuous increase in proto-pore concentration
with rising temperature till instability. The model explains current results on
saturated and unsaturated PC lipid bilayers and thicker artificial bilayers
made of diblock copolymers. Pore size distributions are presented for various
values of area expansion and temperature, and the fractal dimension of the pore
edge is evaluated.Comment: 15 pages, 8 figure
Multipolar Reactive DPD: A Novel Tool for Spatially Resolved Systems Biology
This article reports about a novel extension of dissipative particle dynamics
(DPD) that allows the study of the collective dynamics of complex chemical and
structural systems in a spatially resolved manner with a combinatorially
complex variety of different system constituents. We show that introducing
multipolar interactions between particles leads to extended membrane structures
emerging in a self-organized manner and exhibiting both the necessary
mechanical stability for transport and fluidity so as to provide a
two-dimensional self-organizing dynamic reaction environment for kinetic
studies in the context of cell biology. We further show that the emergent
dynamics of extended membrane bound objects is in accordance with scaling laws
imposed by physics.Comment: submitted to CMSB 0