Morphology and phase behavior of two types of unilamellar vesicles prepared from synthetic phosphatidylcholines studied by freeze-fracture electron microscopy and calorimetry

摘要: Abstract Differential scanning calorimetry and freeze-fracture electron microscopy have been used to characterize the phase behavior morphology of two types unilamellar vesicles composed synthetic phosphatidylcholines. The first type displayed an average diameter roughly 100 nm was formed by slow dilution dialysis octylglucoside-solubilized lipid. These large, were termed dialyzed, octylglucoside could be obtained as a fairly well defined uniform population vesicles. second vesicle prepared unique procedure involving deoxycholate-solubilized lipid at its pre-transition temperature. This produced much more heterogeneous distribution sizes (500 4000 in diameter) left some dilamellar oligolamellar species which not conveniently separated from giant, constituting major portion sample. Both populations similar, but identical that multilamellar (LMV). Fracture-face gel also observed differ between species. LMV previously shown clear undulated or banded fracture-faces P β′ phase, while are here facetted fracture-faces. Giant, faint similar less distinct than β ′ phase. results demonstrated bilayer apposition is required support fracture-face characteristic limiting curvature necessary.