Munro Jeffrey C, Frank Curtis W
Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, USA.
Langmuir. 2004 Nov 23;20(24):10567-75. doi: 10.1021/la048378o.
Inclusion of a polymer cushion between a lipid bilayer membrane and a solid surface has been suggested as a means to provide a soft, deformable layer that will allow for transmembrane protein insertion and mobility. In this study, mobile, tethered lipid bilayers were formed on a poly(ethylene glycol) (PEG) support via a two-step adsorption process. The PEG films were prepared by coadsorbing a heterofunctional, telechelic PEG lipopolymer (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-2000-N-[3-(2-(pyridyldithio)propionate]) (DSPE-PEG-PDP) and a nonlipid functionalized PEG-PDP from an ethanol/water mixture, as described in a previous paper (Munro, J. C.; Frank, C. W. Langmuir 2004, 20, 3339-3349). Then a two-step lipid adsorption strategy was used. First, lipids were adsorbed onto the PEG support from a hexane solution. Second, vesicles were adsorbed and fused on the surface to create a bilayer in an aqueous environment. Fluorescence recovery after photobleaching experiments show that this process results in mobile bilayers with diffusion coefficients on the order of 2 microm2/s. The mobility of the bilayers is decreased slightly by increasing the density of tethered lipids. The formation of bilayers, and not multilayer structures, is also confirmed by surface plasmon resonance, which was used to determine in situ film thickness, and by fluorimetry, which was used to determine quantitatively the fluorescence intensity for each 18 by 18 mm sample. Unfortunately, fluorescence microscopy also shows that there are large defects on the samples, which limits the utility of this system.
有人提出在脂质双分子层膜和固体表面之间加入聚合物垫层，作为提供一个柔软、可变形层的方法，该层将允许跨膜蛋白插入和移动。在本研究中，通过两步吸附过程在聚乙二醇（PEG）载体上形成了可移动的、 tethered脂质双分子层。PEG膜是通过从乙醇/水混合物中共吸附一种异功能、遥爪PEG脂聚合物（1,2 - 二硬脂酰 - sn - 甘油 - 3 - 磷酸乙醇胺 - N - 聚（乙二醇） - 2000 - N - [3 - （2 - （吡啶二硫代）丙酸酯）]（DSPE - PEG - PDP）和一种非脂质功能化的PEG - PDP制备的，如前一篇论文所述（Munro, J. C.; Frank, C. W. Langmuir 2004, 20, 3339 - 3349）。然后采用两步脂质吸附策略。首先，脂质从己烷溶液吸附到PEG载体上。其次，囊泡吸附并融合在表面上，在水性环境中形成双分子层。光漂白后荧光恢复实验表明，该过程产生的可移动双分子层的扩散系数约为2平方微米/秒。通过增加 tethered脂质的密度，双分子层的流动性略有降低。表面等离子体共振用于原位测定膜厚度，荧光法用于定量测定每个18×18毫米样品的荧光强度，这也证实了形成的是双分子层而不是多层结构。不幸的是，荧光显微镜也显示样品上存在大的缺陷，这限制了该系统的实用性。
