%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 }