Molecular-scale structural and functional characterization of sparsely tethered bilayer lipid membranes
Molecular-scale structural and functional characterization of sparsely tethered bilayer lipid membranes
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DOI：
10.1116/1.2709308
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发表时间：
2007-03-01
期刊：
影响因子：
2.1
通讯作者：
Losche, Mathias
中科院分区：
文献类型：
--
作者：
McGillivray, Duncan J.;Valincius, Gintaras;Losche, Mathias
用磷脂和合成的1-硫己酸（环氧乙烷）脂质WC14在金表面形成表面系固仿生双层膜（系固双层脂质膜）。利用电化学阻抗谱、中子反射（NR）和傅里叶变换红外反射吸收光谱（FT-IRRAS）对其进行了表征，获得了功能和结构信息。作者发现，具有高表面覆盖率的电绝缘膜（电导率和电容分别低至1 μ S cm（-2）和0.6 μ F cm(-2)）可以由一系列脂质通过简单的两步过程形成，该过程包括形成自组装单层（SAM）和通过“快速溶剂交换”完成双层。NR提供了界面结构的分子分辨表征，特别是tBLM和固体支撑之间空间的构成。在基于纯WC14的SAMs的tBLMs中，尽管ft - iras显示该区域结构无序，但六（环氧乙烷）系链区域的水化程度较低。然而，在由WC14与短链“填充剂”β -巯基乙醇共吸附制成的混合SAMs上，根据NR和溶剂的对比变化判断，tBLM和底物之间的膜下空间含有高达60%的可交换溶剂。从低WC14比例的溶液中化学吸附的sam可以很容易地制备完整和稳定的“稀疏系”blm （stblm）。具有不饱和或饱和、直链或支链的磷脂都形成了性质相似的stblm。(C) 2007年美国真空学会。
Surface-tethered biomimetic bilayer membranes (tethered bilayer lipid membranes (tBLMs)) were formed on gold surfaces from phospholipids and a synthetic 1-thiahexa(ethylene oxide) lipid, WC14. They were characterized using electrochemical impedance spectroscopy, neutron reflection (NR), and Fourier-transform infrared reflection-absorption spectroscopy (FT-IRRAS) to obtain functional and structural information. The authors found that electrically insulating membranes (conductance and capacitance as low as 1 mu S cm(-2) and 0.6 mu F cm(-2), respectively) with high surface coverage (> 95% completion of the outer leaflet) can be formed from a range of lipids in a simple two-step process that consists of the formation of a self-assembled monolayer (SAM) and bilayer completion by "rapid solvent exchange." NR provided a molecularly resolved characterization of the interface architecture and, in particular, the constitution of the space between the tBLM and the solid support. In tBLMs based on SAMs of pure WC14, the hexa (ethylene oxide) tether region had low hydration even though FT-IRRAS showed that this region is structurally disordered. However, on mixed SAMs made from the coadsorption of WC14 with a short-chain "backfiller," beta-mercaptoethanol, the submembrane spaces between the tBLM and the substrates contained up to 60% exchangeable solvent by volume, as judged from NR and contrast variation of the solvent. Complete and stable "sparsely tethered" BLMs (stBLMs) can be readily prepared from SAMs chemisorbed from solutions with low WC14 proportions. Phospholipids with unsaturated or saturated, straight or branched chains all formed qualitatively similar stBLMs. (C) 2007 American Vacuum Society.