MEMPHYS Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark.
Biophys J. 2012 Dec 5;103(11):2304-10. doi: 10.1016/j.bpj.2012.10.031.
We have developed a strategy to determine lengths and orientations of tie lines in the coexistence region of liquid-ordered and liquid-disordered phases of cholesterol containing ternary lipid mixtures. The method combines confocal-fluorescence-microscopy image stacks of giant unilamellar vesicles (GUVs), a dedicated 3D-image analysis, and a quantitative analysis based in equilibrium thermodynamic considerations. This approach was tested in GUVs composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-palmitoyl-sn-glycero-3-phosphocholine/cholesterol. In general, our results show a reasonable agreement with previously reported data obtained by other methods. For example, our computed tie lines were found to be nonhorizontal, indicating a difference in cholesterol content in the coexisting phases. This new, to our knowledge, analytical strategy offers a way to further exploit fluorescence-microscopy experiments in GUVs, particularly retrieving quantitative data for the construction of three lipid-component-phase diagrams containing cholesterol.
我们已经开发出一种策略，用于确定胆固醇含量的三元脂质混合物液有序相与液无序相共存区域内连接线的长度和方向。该方法结合了巨单层囊泡（GUV）的共聚焦荧光显微镜图像堆栈、专用的 3D 图像分析以及基于平衡热力学考虑的定量分析。该方法在由 1,2-二油酰基-sn-甘油-3-磷酸胆碱/1,2-棕榈酰基-sn-甘油-3-磷酸胆碱/胆固醇组成的 GUV 中进行了测试。一般来说，我们的结果与先前用其他方法获得的报告数据有较好的一致性。例如，我们计算出的连接线不是水平的，表明共存相中的胆固醇含量存在差异。这种新的、据我们所知的分析策略为进一步利用 GUV 中的荧光显微镜实验提供了一种方法，特别是为构建含有胆固醇的三脂质组分相图提供了定量数据。
