3D Probed Lipid Dynamics in Small Unilamellar Vesicles
3D Probed Lipid Dynamics in Small Unilamellar Vesicles
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DOI：
10.1002/smll.201603408
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发表时间：
2017-04-04
期刊：
影响因子：
13.3
通讯作者：
Lin, King-Chuen
中科院分区：
文献类型：
--
作者：
Chao, Meng-Hsuan;Lin, Yen-Ting;Lin, King-Chuen
单分子荧光相关光谱克服了光学显微镜（10近似至20 nm）的分辨率障碍，用于观察小单层囊泡（suv；直径< 100 nm）中的脂质动力学。在单分子水平上获得了脂质样示踪剂1,1'-二十八烷基-3,3,3',3'-四甲基二碳菁（DiD）在膜双层中的荧光轨迹。自相关分析得到了suv膜中脂质组织、氧转运和横向扩散的动力学信息。首先，与DiD发色团形成结构偶联的胆固醇的加入可能会限制异构化的可行性。其次，氧的运输被阻止从超小簇和富含胆固醇的区域，而它可以通过具有液体无序相（Ld）和缺陷的膜区域。第三，通过分析脂质扩散系数与三态寿命相关的二维光谱，可以精确地显示脂质双分子层的非均质性，如不同相的脂质结构域、脂质填充缺陷以及did诱导的“束状”超小簇。
Single-molecule fluorescence correlation spectroscopy overcomes the resolution barrier of optical microscopy (10 approximate to-20 nm) and is utilized to look into lipid dynamics in small unilamellar vesicles (SUVs; diameter < 100 nm). The fluorescence trajectories of lipid-like tracer 1,1'-dioctadecyl-3,3,3', 3'-tetramethylindodicarbocyanine (DiD) in the membrane bilayers are acquired at a single-molecule level. The autocorrelation analysis yields the kinetic information on lipid organization, oxygen transport, and lateral diffusion in SUVs' membrane. First, the isomerization feasibility may be restricted by the addition of cholesterols, which form structure conjugation with DiD chromophore. Second, the oxygen transport is prevented from the ultrasmall cluster and cholesterol-rich regions, whereas it can pass through the membrane region with liquid-disordered phase (Ld) and defects. Third, by analyzing 2D spectra correlating the lipid diffusion coefficient and triplet-state lifetime, the heterogeneity in lipid bilayer can be precisely visualized such as lipid domain with different phases, the defects of lipid packing, and DiD-induced "bouquet" ultrasmall clusters.