Avtor/Urednik		Peterlin, Primož; Arrigler, Vesna; Kogej, Ksenija; Svetina, Saša; Walde, Peter
Naslov		Growth and shape transformations of giant phospholipid vesicles upon interaction with an aqueous oleic acid suspension
Tip		članek
Vir		Chem Phys Lipids
Vol. in št.		Letnik 159, št. 2
Leto izdaje		2009
Obseg		str. 67-76
Jezik		eng
Abstrakt		The interaction of two types of vesicle systems was investigated: micrometer-sized, giant unilamellar vesicles (GUVs) formed from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and submicrometer-sized, large unilamellar vesicles (LUVs) formed from oleic acid and oleate, both in a buffered aqueous solution (pH 8.8). Individual POPC GUVs were transferred with a micropipette into a suspension of oleic acid/oleate LUVs, and the shape changes of the GUVs were monitored using optical microscopy. The behavior of POPC GUVs upon transfer into a 0.8mM suspension of oleic acid, in which oleic acid/oleate forms vesicular bilayer structures, was qualitatively different from the behavior upon transfer into a 0.3mMsuspension of oleic acid/oleate, in which oleic acid/oleate is predominantly present in the form of monomers and possibly non-vesicular aggregates. In both cases, changes in vesicle morphology were observed within tens of seconds after the transfer. After an initial increase of the vesicle cross-section, the vesicle started to evaginate, spawning dozens of satellite vesicles connected to the mother vesicle with narrow necks or tethers. In 60% of the cases of transfer into a 0.8mM oleic acid suspension, the evagination process reversed and proceeded to the point where the membrane formed invaginations. In some of these cases, several consecutive transitions between invaginated and evaginated shapeswere observed. In the remaining 40% of the cases of transfer into the 0.8mMoleic acid suspension and in all cases of vesicle transfer into the 0.3mMoleic acid suspension, no invaginations nor subsequent evaginations were observed. An interpretation of the observed vesicle shape transformation on the basis of the bilayer-couple model is proposed, which takes into account uptake of oleic acid/oleate molecules by the POPC vesicles, oleic acid flip-flop processes and transient pore formation.
Deskriptorji		MEMBRANES, ARTIFICIAL MEMBRANE LIPIDS PARTICLE SIZE OLEIC ACIDS OSMOLAR CONCENTRATION SPECTROMETRY, FLUORESCENCE