Adsorption of lipid-functionalized poly(ethylene glycol) to gold surfaces as a cushion for polymer-supported lipid bilayers
Adsorption of lipid-functionalized poly(ethylene glycol) to gold surfaces as a cushion for polymer-supported lipid bilayers
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DOI：
10.1021/la036062v
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发表时间：
2004-04-13
期刊：
影响因子：
3.9
通讯作者：
Frank, CW
中科院分区：
文献类型：
--
作者：
Munro, JC;Frank, CW
已建议在脂质双层膜和固体表面之间包含聚合物垫作为提供柔软的可变形层的方法，该层将允许跨膜蛋白质插入和移动。在本研究中，使用多种表面敏感技术研究了从乙醇和水溶液吸附到金表面上的异功能遥爪 PEG 脂质聚合物（1,2-二硬脂酰基 - 甘油-3-磷酸乙醇胺-N-聚（乙二醇）-2000-N-[3-（2-（吡啶基二硫代）丙酸酯）（DSPE-PEG-PDP））的特性。当 PEG 分子通过硫醇键吸附到金表面时，反射吸收红外光谱显示，形成了具有无序 DSPE 烷基链的无定形 PEG 层，与吸附时间或溶液浓度无关。根据脂质聚合物膜上水和十六烷接触角的前进和后退，DSPE 脂质基团似乎从 PEG 层分离并暴露在聚合物膜的表面。等离子体共振实验和观察到的大接触角滞后表明，这些 PEG 层的自组装和无定形特性使其成为聚合物支撑的脂质双层的理想候选材料，通过改变 DSPE-PEG-PDP 与乙醇的吸附时间，可以在一定程度上控制 DSPE-PEG-PDP。来自乙醇/水混合物的非脂质功能化 PEG-PDP，允许 PEG 厚度和密度保持恒定，同时降低 DSPE 基团的密度。
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, the properties of a heterofunctional, telechelic PEG lipopolymer (1,2-distearoylsn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-2000-N-[3-(2-(pyridyldithio)propionatel) (DSPE-PEG-PDP) adsorbed from ethanol and water solutions onto gold surfaces were studied using a variety of surface-sensitive techniques. X-ray photoelectron spectroscopy showed that the PEG molecules are tethered to the gold surface via thiolate bonds. When adsorbed from water, ethanol, or their mixtures, reflection-absorption infrared spectroscopy showed that amorphous PEG layers with disordered DSPE alkyl chains were formed, independent of adsorption time or solution concentration. On the basis of advancing and receding water and hexadecane contact angles on the lipopolymer films, the DSPE lipid groups appear to segregate from the PEG layer and become exposed at the surface of the polymer films. Swelling observed in surface plasmon resonance experiments and the large contact angle hysteresis observed indicate that highly swellable, mobile films capable of molecular rearrangements are formed. The self-assembling and amorphous properties of these PEG layers make them ideal candidates as polymer cushions for polymer-supported lipid bilayers. The DSPE surface concentration can be controlled, to a limited degree, by varying the adsorption time of DSPE-PEG-PDP from ethanol. A more effective strategy is to coadsorb DSPE-PEG-PDP with a non-lipid-functionalized PEG-PDP from an ethanol/water mixture, which allows the PEG thickness and density to remain constant while decreasing the density of DSPE groups.