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 (similar0.5 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.
%0 Journal Article
%1 C3SM52290C
%A Shinoda, Wataru
%A Discher, Dennis E.
%A Klein, Michael L.
%A Loverde, Sharon M.
%D 2013
%I The Royal Society of Chemistry
%J Soft Matter
%K imported
%N 48
%P 11549-11556
%R 10.1039/C3SM52290C
%T Probing the structure of PEGylated-lipid assemblies by coarse-grained molecular dynamics
%U http://dx.doi.org/10.1039/C3SM52290C
%V 9
%X 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 (similar0.5 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.
@article{C3SM52290C,
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 ([similar]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.},
added-at = {2016-05-13T19:21:35.000+0200},
author = {Shinoda, Wataru and Discher, Dennis E. and Klein, Michael L. and Loverde, Sharon M.},
biburl = {https://www.bibsonomy.org/bibtex/21c986ce61781b37ca42c5f58858e45c5/templehpc},
doi = {10.1039/C3SM52290C},
interhash = {0b9db68707792404da6a57f05136795c},
intrahash = {1c986ce61781b37ca42c5f58858e45c5},
journal = {Soft Matter},
keywords = {imported},
number = 48,
pages = {11549-11556},
publisher = {The Royal Society of Chemistry},
timestamp = {2016-05-13T19:21:35.000+0200},
title = {Probing the structure of PEGylated-lipid assemblies by coarse-grained molecular dynamics},
url = {http://dx.doi.org/10.1039/C3SM52290C},
volume = 9,
year = 2013
}