We present a theory of unbinding transitions for membranes that interact via short and long receptor/ligand bonds. The detail of unbinding behavior of the membranes is governed by the binding energies and concentrations of receptors and ligands. We investigate the unbinding behavior of these membranes with Monte Carlo simulations and via a comparison with strings. We derive the scaling laws for strings analytically. The exact analytic results provide scaling estimate for membranes in the vicinity of the critical point.
提出了一个多组分流体膜的非束缚转变的唯象模型，其中的非束缚转变用类似于聚合物的Flory-Huggins理论的理论来描述。包合物分子的横向相分离和膜-基底距离之间的耦合解释了两个未结合相之间的相共存，如Marx等人在最近的实验中观察到的[Phys. Rev. Lett. 88，138102（2002）]。在临界终点温度下，我们发现对于多组分膜，解束缚转变为一级反应。
The domain formation of curvature-inducing molecules, such as peripheral or transmembrane proteins and conical surfactants, is studied in thermal equilibrium and nonequilibrium steady states using meshless membrane simulations. These molecules can bind onto both surfaces of a bilayer membrane and also move to the opposite leaflet by a flip-flop. In symmetric conditions for the two leaflets, the membrane domains form checkerboard patterns in addition to stripe and spot patterns. The unbound membrane stabilizes the vertices of the checkerboard. In asymmetric conditions, the domains form kagome-l…
Membrane phase behavior induced by the binding of curvature-inducing proteins is studied by a combination of analytical and numerical approaches. In thermal equilibrium under the detailed balance between binding and unbinding, the membrane exhibits three phases: an unbound uniform flat phase (U), a bound uniform flat phase (B), and a separated/corrugated phase (SC). In the SC phase, the bound proteins form hexagonally-ordered bowl-shaped domains. The transitions between the U and SC phases and between the B and SC phases are second order and first order, respectively. At a small spontaneous cu…
Liposomes that achieve a heterogeneous and spatially organized surface through phase separation have been recognized to be a promising platform for delivery purposes. However, their design and optimization through experimentation can be expensive and time-consuming. To assist with the design and reduce the associated cost, we propose a computational platform for modeling membrane coarsening dynamics based on the principles of continuum mechanics and thermodynamics. This model couples phase separation to lateral flow and accounts for different membrane fluidity within the different phases, whic…
Membrane phase-separation is a mechanism that biological membranes often use to locally concentrate specific lipid species in order to organize diverse membrane processes. Phase separation has also been explored as a tool for the design of liposomes with heterogeneous and spatially organized surfaces. These "patchy" liposomes are promising platforms for delivery purposes, however their design and optimization through experimentation can be expensive and time-consuming. We developed a computationally efficient method based on the surface Cahn-Hilliard phase-field model to complement experimenta…
Designing Multivalent Copolymers for Selective Targeting of Multicomponent Surfaces
Faculty of Chemistry and Chemical Engineering, University of Maribor（马里博尔大学化学与化工学院）；The Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska（沿海大学数学、自然科学与信息技术学院）；Institute for Environmental Protection and Sensors（环境保护与传感器研究所）；Department of Materials Science and Engineering, Johns Hopkins University（约翰斯·霍普金斯大学材料科学与工程系）
Clustering of ligand-binding receptors of different types on thickened isles of the cell membrane, namely lipid rafts, is an experimentally observed phenomenon. Although its influence on cell response is deeply investigated, the role of the coupling between mechanical processes and multiphysics involving the active receptors and the surrounding lipid membrane during ligand-binding has not yet been understood. Specifically, the focus of this work is on G-protein-coupled receptors (GPCRs), which regulate specific cell processes through chemical signalling pathways involving a synergistic balance…
