Disc formation in cholesterol-free lippsornes during phase transition

Cryogenic transmission electron microscopy (cryo-TEM) images of lysolipid-containing thermosensitive liposomes (LTSL). revealed that open liposomes and bilayer discs appeared when liposomes were cycled through the gel (L-beta') to liquid-crystalline (L-alpha) phase transition. The amount of bilayer discs generated was dependent on the combined presence of PEG-lipid and lysolipid in the membrane. We hypothesize that micelle-forming membrane components stabilize the rim of bilayer openings and membrane discs that form when liposomes are cycled through T-C. (C) 2003 Published by Elsevier B.V.