Spontaneously formed unilamellar vesicles with path-dependent size distribution.
We observe the spontaneous formation of path-dependent monodisperse and polydisperse phospholipid unilamellar vesicles (ULV) from two different equilibrium morphologies specifically, disklike micelles and extended lamellae, respectively. On heating beyond a temperature Tc, low temperature disklike micelles, or so-called bicelles, transform into lamellae. Dilution of the lamellar phase, at a fixed temperature, results in a complete unbinding transition and the formation of polydisperse ULV, demonstrating the instability of the lamellar phase. On the other hand, heating of a dilute bicellar phase above Tc results in monodisperse ULV, which on cooling revert back to bicelles for lipid concentrations phi > or = 0.5 wt % and transform into oblate ellipsoids for phi = 0.1 wt %, a morphology not previously seen in "bicellar" lipid mixtures. Monodisperse ULV reform on heating of the oblate ellipsoids.
Nieh
Mu-Ping
MP
National Research Council, Steacie Institute for Molecular Sciences, Chalk River, Ontario, K0J 1J0, Canada.
Raghunathan
Velayudhan A
VA
Kline
Steve R
SR
Harroun
Thad A
TA
Huang
Chien-Yueh
CY
Pencer
Jeremy
J
Katsaras
John
J