A phase of liposomes with entangled tubular vesicles

An equilibrium phase belonging to the family of bilayer liposomes
in ternary mixtures of dimyristoylphosphatidylcholine (DMPC),
water, and geraniol (a biological alcohol derived from oil-soluble
vitamins that acts as a cosurfactant) has been identified. Electron
and optical microscopy reveal the phase, labeled Ltv, to be
composed of highly entangled tubular vesicles. In situ x-ray
diffraction confirms that the tubule walls are multilamellar with
the lipids in the chain-melted state. Macroscopic observations show
that the Ltv phase coexists with the well-known L4 phase of
spherical vesicles and a bulk L alpha phase. However, the defining
characteristic of the Ltv phase is the Weissenberg rod climbing
effect under shear, which results from its polymer-like entangled
microstructure.