Membrane curvature plays a crucial role in the realization of many cellular membrane functions such as signaling and trafficking. Here, using coarse-grained molecular dynamics (MD) simulation, we present an effective method of producing curved model membranes and systematically investigated the interplay between the curvature and lateral sorting of lipids and transmembrane (TM) peptides/proteins in the model membranes. We first confirmed the experimental results of the lateral organization of lipid domains in curved ternary membranes. Then, we focused on exploring the lateral sorting of TM peptides/proteins with symmetric shape in the curved membranes. The results showed that the lateral inhomogeneous packing of lipids induced by the curvature and/or the component heterogeneity drives the peptides/proteins to accumulate in the curved regions in both the unary and ternary membranes. However, whether the peptides/proteins can stably and compactly reside in the curved regions is determined by their final packing configuration, which may be influenced by the membrane curvature in the curved regions. Additionally, the insertion of peptides/proteins may enhance the membrane curvature. This work provided some theoretical insights into understanding the mechanism of the interplay of membrane curvature and lateral organization (especially the lateral sorting of the peptides/proteins with symmetric shape) in the biomembrane in some biological processes.

Surface functionalization is an efficient method to modify the properties of nanoparticles for nanomedical and other applications. Here, we investigate the penetration of polymer-grafted nanoparticles through a lipid bilayer using self-consistent field theory. We examine the morphological deformation of the polymer-grafted nanoparticles and the lipid bilayer and the variation of the free energy of the system during the penetration of the nanoparticles grafted by polymers with different chain lengths and densities. It is found that the nanoparticles grafted by long polymers can penetrate through the lipid bilayer more easily. Additionally, with varying the grafting density, we find two different penetration pathways of the polymer-grafted nanoparticles. For the nanoparticle grafted by polymers with low density, the lipid bilayer is curved by the nanoparticle when the nanoparticle is inserted into the bilayer shallowly and then a pore is formed when the nanoparticle is inserted into the bilayer deeply enough; whereas, for the nanoparticle grafted by polymers with high density, the lipid bilayer is not curved before and after the pore formation. We further reveal the underlying mechanism of these two different penetration pathways. The results may yield some theoretical insights into the applications of nanoparticles in nanomedicine.

Investigations of the interactions between nanoparticles and lipid bilayer may yield insight into the understanding of the protein−biomembrane interactions and the cytotoxicity of drugs. Here, we theoretically investigate the membrane-mediated interactions between two nanoparticles supported on a substrate. We examine the effects of the packing density of lipids, the direct nanoparticle−lipid interaction, and the direct substrate−lipid interaction on the effective interactions between the nanoparticles and find the effective interactions between the two nanoparticles are mainly dominated by the competition of the deformations of the different parts of the lipid bilayers as well as the stretching of the lipid chains sandwiched between the nanoparticles. By varying the above-mentioned effects, the effective interactions between the two nanoparticles can be efficiently modulated. The results may provide some theoretical insight into experiments on the membrane-mediated nanoparticle organization on a substrate and organization of the membrane proteins or drug nanoparticles on the surfaces of the cellular membranes.