Phase Behavior of a Lipid/Polymer-Lipid Mixture in Aqueous Medium


Journal Article

The phase behavior of a mixture of bilayer forming lipids and polymer-lipids (lipids with covalently attached polymer to their hydrophilic moieties) in excess water is studied theoretically. The mixture is predicted to exhibit complex phase behavior for polymer molecular weights 2000 and 5000, depending on the concentration (fraction) of polymer-lipids in the lipid mixture. The bilayer is characterized by a maximal concentration nMt (saturation limit) of polymer-lipids that it can incorporate, as determined by its material properties (elastic modulus of area expansion and critical area expansion). At a different concentration ntr, which we call the thermodynamics crossover, micelle formation becomes energetically favorable over bilayer formation. We show that for DSPC and SOPC bilayers ntr < nsat. Increase of the polymer-lipid concentration above ntr leads to a gradual transition from a bilayer to a micellar phase; bilayers and micelles can coexist. In the transition region the polymer-lipid concentration is higher in the micellar phase than in the coexisting bilayer. © 1995, American Chemical Society. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Hristova, K; Needham, D

Published Date

  • July 1, 1995

Published In

Volume / Issue

  • 28 / 4

Start / End Page

  • 991 - 1002

Electronic International Standard Serial Number (EISSN)

  • 1520-5835

International Standard Serial Number (ISSN)

  • 0024-9297

Digital Object Identifier (DOI)

  • 10.1021/ma00108a029

Citation Source

  • Scopus