POLYMERIZATION-INDUCED SHRINKAGE IN GIANT BUTADIENIC LIPID VESICLES

A new butadienic lipid, dimethylbis[2(tetradeca-2,4-dienoyl)oxyethyl]ammonium bromide, has been used to form giant vesicles. Under UV irradiation, a spectacular change in the morphology of these vesicles is observed: a global shrinkage, along with a thickening or crumpling of the membrane (depending upon the conditions of irradiation). The kinetics of the shrinkage are totally different (much slower) than those of the polymerization (monitored by the disappearance of the absorption due to the conjugated double bonds of the diene at 262 nm). This is indicative of a two-step process: the shrinkage resulting from rapid polymerization followed by slow expulsion of part of the water inside the vesicles.