Issue 48, 2013

Probing the structure of PEGylated-lipid assemblies by coarse-grained molecular dynamics

Abstract

Poly(ethylene glycol) (PEG) and various zwitterionic species are now used routinely as components in soft biomaterials. The study of mixtures composed of PEGylated-lipids with zwitterionic lipids provides an excellent opportunity to understand molecular interactions in such systems. To this end, we examine the liposome/bicelle/micelle phase behavior of such mixtures in bulk solution and as monolayers at the air–water interface, utilizing a coarse-grained molecular-dynamics (CG-MD) approach rooted in experimental parameters that inform the nature of the short-range interactions. Specifically, we examine mixtures of PEGylated lipid and dimyristoylphosphatidylcholine (DMPC) lipid monolayers and find the standard force fields yield calculated surface tensions in agreement with experiment. Long-time CG-MD simulations (∼0.5 microsecond) of the self-assembly for different concentrations of PEG indicate the critical micellar size for the aggregate to form a bicelle from a spherical micellar nucleus. At lower PEG concentrations we find self-assembly of the PEGylated lipid into a liposome coexisting with a mixture of smaller bicelles. Examination of large individual bicelles (1000 lipids) at increasing concentrations of PEG indicates that the degree of PEG de-mixing towards the outer radius of the bicelle is correlated with the overall concentration of PEG in the bicelle. The CG-MD approach used herein should be a useful complement to experimental studies designed to probe solute (drug) interactions with such membrane systems.

Graphical abstract: Probing the structure of PEGylated-lipid assemblies by coarse-grained molecular dynamics

Supplementary files

Article information

Article type
Paper
Submitted
30 Aug 2013
Accepted
27 Oct 2013
First published
01 Nov 2013

Soft Matter, 2013,9, 11549-11556

Probing the structure of PEGylated-lipid assemblies by coarse-grained molecular dynamics

W. Shinoda, D. E. Discher, M. L. Klein and S. M. Loverde, Soft Matter, 2013, 9, 11549 DOI: 10.1039/C3SM52290C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements