Characterization of physical properties of supported phospholipid membranes using imaging ellipsometry at optical wavelengths
Characterization of physical properties of supported phospholipid membranes using imaging ellipsometry at optical wavelengths
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DOI：
10.1529/biophysj.106.097071
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发表时间：
2007-02-15
影响因子：
3.4
通讯作者：
Parikh, Atul N.
中科院分区：
文献类型：
--
作者：
Howland, Michael C.;Szmodis, Alan W.;Parikh, Atul N.
亚纳米尺度的垂直z分辨率加上大面积的横向成像、无标记、非接触和原位等优点，使得光学成像椭圆偏振技术非常适合于定量表征负载在氧化物基质和水相中的脂类双层。本文通过已有的实例说明了IE在定量表征支撑磷脂膜的结构和功能性质方面的多功能性。这些包括：1)利用光化学刻画的单个1，2-二肉豆蔻基甘油-3-磷酸胆碱双层一步法测定双层厚度至0.2 nm的精度和大面积的横向均一性；2)单液相1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine双层的水化诱导扩散动力学；说明原位能力和图像获取速度；3)1)二月桂酰-sn-甘油-3-磷酸胆碱和半乳糖神经酰胺的相分离二元混合物的大面积形态表征；4)霍乱毒素B亚单位与GM(1)-掺入的双层的结合。从这些椭圆偏振测量中得出的其他见解也针对这些应用进行了讨论。与以前的研究一致证实，IE为这些膜性质的常规定量表征提供了一种简单方便的工具。我们的结果还表明，IE通过结合大面积测量和高垂直分辨率来补充更广泛使用的荧光和扫描探针显微镜，而不使用标记的脂类。
Subnanometer-scale vertical z-resolution coupled with large lateral area imaging, label-free, noncontact, and in situ advantages make the technique of optical imaging ellipsometry (IE) highly suitable for quantitative characterization of lipid bilayers supported on oxide substrates and submerged in aqueous phases. This article demonstrates the versatility of IE in quantitative characterization of structural and functional properties of supported phospholipid membranes using previously well-characterized examples. These include 1), a single-step determination of bilayer thickness to 0.2 nm accuracy and large-area lateral uniformity using photochemically patterned single 1,2-dimyristoyl-sn-glycero-3-phosphocholine bilayers; 2), hydration-induced spreading kinetics of single-fluid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers; to illustrate the in situ capability and image acquisition speed; 3), a large-area morphological characterization of phase-separating binary mixtures of 1,2-dilauroyl-sn-glycero-3-phosphocholine and galactosylceramide; and 4), binding of cholera-toxin B subunits to GM(1)-incorporating bilayers. Additional insights derived from these ellipsometric measurements are also discussed for each of these applications. Agreement with previous studies confirms that IE provides a simple and convenient tool for a routine, quantitative characterization of these membrane properties. Our results also suggest that IE complements more widely used fluorescence and scanning probe microscopies by combining large-area measurements with high vertical resolution without the use of labeled lipids.