Title:	Structural phase behavior of high-concentration, alignable biomimetic bicelle mixtures
Authors:	Nieh, M.P. Raghunathan, V.A. Glinka, C.J. Harroun, T.A. Katsaras, J.
Keywords:	bicelle DHPC DMPC DMPG lamellae multilamellar vesicle (MLV) neutron diffraction optical microscopy phospholipids ribbons small angle neutron scattering (SANS)
Issue Date:	10-Jan-2005
Publisher:	Wiley InterScience
Citation:	Macromolecular Symposia, 2005, Vol.219, p135-145
Abstract:	The structures of bicelle mixtures composed of dimyristoyl and dihexanoyl phosphatidylcholines (DMPC and DHPC) with DMPC/DHPC molar ratios of 3.2 and 5 are characterized using polarized optical microscopy (POM) and small angle neutron scattering (SANS). Three phases, isotropic (I), chiral nematic (N*) and smectic (S) are observed as temperature (T) varies from 10 to 70 °C. The structure of the magnetically alignable N* phase, which was previously considered to be made up of discoidal micelles, is found to be composed of ribbons. Doping with the charged lipid, dimyristoyl phosphatidylglycerol (DMPG), which has the same 14:0 hydrocarbon chains as DMPC, results in a structural change of the aggregates where only the isotropic and smectic phases are observed. The smectic phase for the mixtures doped with DMPG is shear-alignable and follows one-dimensional swelling. However, at high-T zwitterionic DMPC/DHPC mixtures form multi-lamellar vesicles (MLV) with a relatively constant lamellar spacing of 66 Å, independent of water content.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/2310
ISSN:	1022-1360
Alternative Location:	http://dx.doi.org/10.1002/masy.200550112
Copyright:	2005 Wiley InterScience
Appears in Collections:	Research Papers (SCM)

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