LiposomesUnilamellar LiposomesPhosphatidylcholinesDrug Carriers1,2-DipalmitoylphosphatidylcholineLipid BilayersCholesterolPhospholipidsKineticsPhosphatidylethanolaminesDimyristoylphosphatidylcholineMembranes, ArtificialMembrane LipidsPhosphatidylglycerolsFluoresceinsMembrane FluidityPhosphatidylserinesSpectrometry, FluorescenceParticle SizeMembrane FusionScattering, RadiationCalorimetry, Differential ScanningSphingomyelinsPermeabilityPolyethylene GlycolsFreeze FracturingFluorescent DyesLauratesMicellesBiophysicsPhase TransitionTemperatureDrug Delivery SystemsLipidsBiophysical PhenomenaDiphenylhexatrieneMolecular Conformation2-NaphthylamineProteolipidsHydrogen-Ion ConcentrationCell MembraneCationsMicroscopy, Fluorescence