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Brock University : Physics Department : Thad Harroun : Research  
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Mesophases of bicellar mixtures

"Bicelle" is a term used to describe a disc-like, bilayerd micelle formed from mixing long and short chain phospholipids. The commonly used recipe for bicelles is C14:0 and C6:0 phosphatidylcholine (DMPC and DHPC). These mixtures have proved very useful in the study of membrane proteins by NMR. However, there are a number of liquid crystal phases that can be formed from these mixtures, beyond the simple bicelle. Here we present the dominant mesophases that we have determined exist when the molar ratio of DMPC to DHPC is larger than 2.

Click on a picture for a larger version. In each picture, light blue represents the short chain lipid, and red the long chain lipid.

Isotropic - Bicelles

The isotropic phase of bilayered micelles is considerd by many to be the model of "ideal" bicelles. The flat area of the disc (red) is a bilayer of DMPC, and the rim (blue) a curved monolayer of DHPC.

isotropic phase of bicelles

Nematic - Bicelles

When doped with a chraged lipid or a Lanthenide series ion, bicelles have a positive magnetic susceptibility, and undergo an isotrpic to nematic phase transition in a magnetic field.

nematic phase of bicelles

More mesophases...