Transition from unilamellar to bilamellar vesicles induced by an amphiphilic biopolymer.

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TitleTransition from unilamellar to bilamellar vesicles induced by an amphiphilic biopolymer.
Publication TypeJournal Article
Year of Publication2006
AuthorsLee, J-H, Agarwal, V, Bose, A, Payne, GF, Raghavan, SR
JournalPhys Rev Lett
Volume96
Issue4
Pagination048102
Date Published2006 Feb 3
ISSN0031-9007
KeywordsChitosan, Cryoelectron Microscopy, Hydrophobic and Hydrophilic Interactions, Lipid Bilayers, Membranes, Artificial, Phase Transition
Abstract

We report some unusual structural transitions upon the addition of an amphiphilic biopolymer to unilamellar surfactant vesicles. The polymer is a hydrophobically modified chitosan and it embeds its hydrophobes in vesicle bilayers. We study vesicle-polymer mixtures using small-angle neutron scattering (SANS) and cryotransmission electron microscopy (cryo-TEM). When low amounts of the polymer are added to unilamellar vesicles of ca. 120 nm diameter, the vesicle size decreases by about 50%. Upon further addition of polymer, lamellar peaks are observed in the SANS spectra at high scattering vectors. We show that these spectra correspond to a co-existence of unilamellar and bilamellar vesicles. The transition to bilamellar vesicles as well as the changes in unilamellar vesicle size are further confirmed by cryo-TEM. A mechanism for the polymer-induced transitions in vesicle morphology is proposed.

Alternate JournalPhys. Rev. Lett.
PubMed ID16486898