Packing Density Changes of Supported Lipid Bilayers Observed by Fluorescence Microscopy and Quartz Crystal Microbalance-Dissipation
Packing Density Changes of Supported Lipid Bilayers Observed by Fluorescence Microscopy and Quartz Crystal Microbalance-Dissipation
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荧光显微镜和石英晶体微天平耗散观察负载脂质双层的堆积密度变化
DOI：
10.1021/jp503905r
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发表时间：
2014
影响因子：
3.3
通讯作者：
Mahoko Higuchi
中科院分区：
文献类型：
--
作者：
Chiho Kataoka-Hamai;Mahoko Higuchi
支持的脂质双层的各种性质，如扩散和脂质分配的特点。然而，很少有人注意到它们的分子堆积密度。在这项工作中，1，2-二油酰基-3-三甲基铵丙烷（DOTAP）囊泡在玻璃和二氧化硅上的吸附进行了研究，使用荧光显微镜，石英晶体微天平耗散（QCM-D），和原子力显微镜。光漂白后的荧光恢复数据表明，大的单层囊泡（LUVs）在玻璃上的吸附产生支持的双层在碱性（pH 8.3）和酸性（pH 3-4）条件下的充分流动性。这些流体双层表现出相当不同的扩散常数，那些在碱性pH值是10倍以上，在酸性pH值。这种pH值的依赖性的原因是澄清的调查巨大的单层囊泡（GUV）的玻璃破裂。荧光数据显示，在碱性pH值的平面双层补丁的面积增加。因此，我们得出结论，在碱性溶液中的快速扩散所产生的分子密度降低。QCM-D的数据表明，耗散逐步增加，在碱性pH值的二氧化硅囊泡融合过程中。我们将这种行为的平面双层的堆积密度的下降。
Various properties of supported lipid bilayers such as diffusion and lipid partitioning are well characterized. However, little attention has been paid to their molecular packing density. In this work, the adsorption of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) vesicles on glass and silicon dioxide was investigated using fluorescence microscopy, quartz crystal microbalance-dissipation (QCM-D), and atomic force microscopy. Fluorescence recovery after photobleaching data showed that the adsorption of large unilamellar vesicles (LUVs) on glass yielded supported bilayers with full mobility under alkaline (pH 8.3) and acidic (pH 3–4) conditions. These fluid bilayers exhibited quite different diffusion constants; those at alkaline pH were ∼10 times larger than those at acidic pH. The reason for this pH dependence was clarified by investigation of the rupture of giant unilamellar vesicles (GUVs) on glass. Fluorescence data revealed that the area of planar bilayer patches increased at alkaline pH. Thus, we conclude that the rapid diffusion in alkaline solution arises from the decreased molecular density. QCM-D data showed that dissipation increased in a stepwise manner during vesicle fusion on silicon dioxide at alkaline pH. We attribute this behavior to the decrease in packing density of planar bilayers.