The fluidity and polar environment of ~100 nm hybrid vesicles combining dipalmitoylphosphatidylcholine (DPPC) and poly(1,2-butadiene)-block-polyethylene oxide (PBd-PEO, average molecular weight 950 g/mol) were studied upon vesicle heating using the fluorescence spectroscopy techniques of DPH anisotropy and laurdan generalized polarization (GP). These techniques indicated PBd-PEO membranes are less ordered than solid DPPC, but slightly more ordered than fluid DPPC or dioleoylphosphatidylcholine (DOPC) membranes. We find the DPH anisotropy values are less than expected from additivity of the components' anisotropies in the fluid phase mixture of DPPC and PBd-PEO, inferring that DPPC strongly fluidizes the PBd-PEO. We use transitions in DPH anisotropy and laurdan GP to create a temperature/composition phase diagram for DPPC/PBd-PEO which we find displays a significantly broader solid/fluid phase coexistence region than DPPC/DOPC, showing that DPPC partitions less readily into fluid PBd-PEO than into fluid DOPC. The existence of a broad solid/fluid phase coexistence region in DPPC/PBd-PEO vesicles is verified by Förster resonance energy transfer results and the visualization of phase separation in giant unilamellar vesicles containing up to 95% PBd-PEO and a single phase in 100% PBd-PEO vesicles at room temperature. These results add to the limited knowledge of phase behavior and phase diagrams of hybrid vesicles, and should be useful in understanding and tailoring membrane surface architecture toward biomedical applications such as drug delivery or membrane protein reconstitution.

结合二棕榈酰磷脂酰胆碱（DPPC）和聚（1,2-丁二烯）-嵌段的〜100 nm混合囊泡的流动性和极性环境使用DPH各向异性和laurdan广义极化（GP）的荧光光谱技术，在囊泡加热条件下研究了聚环氧乙烷（PBd-PEO，平均分子量950 g / mol）。这些技术表明，PBd-PEO膜的排列顺序比固体DPPC的排列顺序少，但比流体DPPC或油酰磷脂酰胆碱（DOPC）膜排列更有序。我们发现，DPH各向异性值小于DPPC和PBd-PEO的液相混合物中各组分的各向异性的加和性，这表明DPPC强烈流化了PBd-PEO。我们使用DPH各向异性和laurdan GP中的跃迁创建了DPPC / PBd-PEO的温度/组成相图，发现该图显示出比DPPC / DOPC宽得多的固相/流相共存区域，结果表明，与在流体DOPC中相比，DPPC不易分配到流体PBd-PEO中。Förster共振能量转移结果证实了DPPC / PBd-PEO囊泡中存在宽广的固/液相共存区域，并且可视化了含有高达95％PBd-PEO和100％单相的巨大单层囊泡中的相分离。室温下，％PBd-PEO囊泡。这些结果增加了对混合囊泡的相行为和相图的有限了解，并且应有助于理解和定制膜表面结构以适应生物医学应用，例如药物递送或膜蛋白重构。Förster共振能量转移结果证实了DPPC / PBd-PEO囊泡中存在宽广的固/液相共存区域，并且可视化了含有高达95％PBd-PEO和100％单相的巨大单层囊泡中的相分离。室温下，％PBd-PEO囊泡。这些结果增加了对混合囊泡的相行为和相图的有限了解，并且应有助于理解和定制膜表面结构以适应生物医学应用，例如药物递送或膜蛋白重构。Förster共振能量转移结果证实了DPPC / PBd-PEO囊泡中存在宽广的固/液相共存区域，并且可视化了含有高达95％PBd-PEO和100％单相的巨大单层囊泡中的相分离。室温下，％PBd-PEO囊泡。这些结果增加了对混合囊泡的相行为和相图的有限了解，并且应有助于理解和定制膜表面结构以适应生物医学应用，例如药物递送或膜蛋白重构。