Formation and characterization of phospholipid monolayers spontaneously assembled at interfaces between aqueous phases and thermotropic liquid crystals
Formation and characterization of phospholipid monolayers spontaneously assembled at interfaces between aqueous phases and thermotropic liquid crystals
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DOI：
10.1021/la0482397
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发表时间：
2005-03-15
期刊：
影响因子：
3.9
通讯作者：
Abbott, NL
中科院分区：
文献类型：
--
作者：
Brake, JM;Daschner, MK;Abbott, NL
本文报道了磷脂（L-α-磷脂酰胆碱-β-油酰-γ-棕榈酰（L-POPC）、二棕榈酰磷脂酰胆碱（DPPC）和L-α-二月桂酰磷脂酰胆碱（L-DLPC））在水相与液晶（LC）4 ′-戊基-4-氰基联苯（4 ′-pentyl-4-cyanobiphenyl）界面上的自组装。通过在金网格（宽度为283 μ m，深度为20 μ m的正方形孔）内容纳LC，在水相和LC之间产生稳定的平面界面。在这些界面处，磷脂的存在和横向组织导致界面驱动的取向。LC内部的转换。通过用荧光标记的脂质（德克萨斯红-1，2-二棕榈酰-sn-甘油基-3-磷酸乙醇胺（TR-DPPE））掺杂磷脂，定量荧光显微镜显示界面处磷脂的饱和覆盖率为单层的饱和覆盖率，相对于水合脂质双层，其面密度类似于49 +/-8%。通过将磷脂从十二烷基三甲基铵和磷脂的囊泡或混合胶束吸附到水性-LC界面，证明了磷脂的面密度从42 +/-10至102 +/-18%饱和单层覆盖率的控制。通过使用激光扫描共聚焦显微镜（LSCM）进行的光漂白后荧光恢复（FRAP）实验显示，对于密集堆积的单层，在与液晶的界面处组装的L-DLPC中的荧光标记的DPPE的横向迁移率为（6 +/- 1）x 10（-12）m（2）/s。磷脂的表面覆盖度和组成的变化导致横向扩散率在（0.2 +/- 0.1）x 10（-12）和（15 +/- 2）x 10（-12）m（2）/s之间变化。我们还观察到的磷脂负载的界面被划分的金网格，从而允许在LC-水界面的磷脂的图案化阵列的创建。
This paper reports an experimental investigation of the self-assembly of phospholipids (L-alpha-phosphatidylcholine-beta-oleoyl-gamma-palmitoyl (L-POPC), dipalmitoyl phosphatidylcholine (DPPC), and L-alpha-dilauroyl phosphatidylcholine (L-DLPC)) at interfaces between aqueous phases and the nematic liquid crystal (LC) 4'-pentyl-4-cyanobiphenyl. Stable planar interfaces between the aqueous phases and LCs were created by hosting the LCs within gold grids (square pores with widths of 283 mu m and depths of 20 mu m). At these interfaces, the presence and lateral organization of the phospholipids leads to interface-driven orientational. transitions within the LC. By doping the phospholipids with a fluorescently labeled lipid (Texas Red-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (TR-DPPE)), quantitative epifluorescence microscopy revealed the saturation coverage of phospholipid at the interface to be that of a monolayer with an areal density of similar to 49 +/- 8% relative to hydrated lipid bilayers. By adsorbing phospholipids to the aqueous-LC interface from either vesicles or mixed micelles of dodecyltrimethylammonium and phospholipid, control of the areal density of phospholipid from 42 +/- 10 to 102 +/- 18% of saturation monolayer coverage was demonstrated. Fluorescence recovery after photobleaching (FRAP) experiments performed by using laser scanning confocal microscopy (LSCM) revealed the lateral mobility of fluorescently labeled DPPE in L-DLPC assembled at the interface with the liquid crystal to be (6 +/- 1) x 10(-12) m(2)/s for densely packed monolayers. Variation of the surface coverage and composition of phospholipid led to changes in lateral diffusivity between (0.2 +/- 0.1) x 10(-12) and (15 +/- 2) x 10(-12) m(2)/s. We also observed the phospholipid-laden interface to be compartmentalized by the gold grid, thus allowing for the creation of patterned arrays of phospholipids at the LC-aqueous interface.