Effects of poly (ethylene glycol) chains conformational transition on the properties of mixed DMPC/DMPE-PEG thin liquid films and monolayers
Effects of poly (ethylene glycol) chains conformational transition on the properties of mixed DMPC/DMPE-PEG thin liquid films and monolayers
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DOI：
10.1016/j.colsurfb.2007.05.006
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发表时间：
2007-10-01
影响因子：
5.8
通讯作者：
Lalchev, Zdravko
中科院分区：
文献类型：
--
作者：
Georgiev, Georgi As.;Sarker, Dipak K.;Lalchev, Zdravko
将DMPC与DMPE-PEG（550）、DMPE-PEG（2000）和DMPE-PEG（5000）共混，在空气-水界面上形成泡沫液体薄膜（TLF）和单分子膜。比较了PEG链的大小（以分子量表示）和蘑菇-刷子构象转变以及成膜分散液中脂质体/胶束比例对DMPC/DMPE-PEG混合膜界面性质的影响，泡沫膜研究表明，DMPE-PEG加入到泡沫TLF中导致（i）膜变薄和黑点扩展的延迟动力学和（ii）膜稳定性。在蘑菇-刷状转变时，由于空间位阻的增加，DMPE-PEG膜的厚度达到25 nm，而纯DMPC膜只有8 nm厚的牛顿黑膜。DMPE-PEG之间的差异是可能的（2000/5000）由DMPE-PEG（550）通过改变泡沫TLF形成机制的能力，与DMPC纯膜相比，DMPE-PEG单分子膜的形成动力学得到改善，平衡表面张力降低，SEM观察显示，DMPE-PEG单分子膜对固体脂质体中的缺陷起到了“平滑”和“封闭”的作用。DMPE-PEG对TLF的稳定作用和对单层TLF的表面张力的降低作用均随PEG分子量和DMPE-PEG浓度的增加而增强。然而，在临界DMPE-PEG浓度（蘑菇到刷构象转变发生）的影响达到最大幅度，这只是略有变化，在进一步DMPE-PEG含量和胶束/脂质体比增加。(C)2007 Elsevier B. V.保留所有权利。
Foam thin liquid films (TLF) and monolayers at the air-Water interface formed by DMPC mixed with DMPE-bonded poly (ethylene glycol)s (DMPE-PEG(550), DMPE-PEG(2000) and DMPE-PEG(5000)) were obtained. The influence of both (i) PEG chain size (evaluated in terms of Mw) and mushroom-to-brush conformational transition and (ii) of the liposome/micelle ratio in the film-forming dispersions, on the interfacial proper-ties of mixed DMPC/DMPE-PEG films was compared.Foam film studies demonstrated that DMPE-PEG addition to foam TLFs caused (i) delayed kinetics of film thinning and black spot expansion and (ii) film stabilization. At the mushroom-to-brush transition, due to steric repulsion increased DMPE-PEG films thickness reached 25 nm while pure DMPC films were only 8 nm thick Newton black films. It was possible to differentiate DMPE-PEG(2000/5000) from DMPE-PEG(550) by the ability to change foam TLF formation mechanism, which could be of great importance for "stealth" liposome design.Monolayer studies showed improved formation kinetics and equilibrium surface tension decrease for DMPE-PEG monolayers compared with DMPC pure films.SEM observations revealed "smoothing" and "sealing" of the defects in the solid-supported layer surface by DMPE-PEGs adsorption, which could explain DMPE-PEGs ability to stabilize TLFs and to decrease monolayer surface tension.All effects in monolayers, foam TLFs and solid-supported layers increased with the increase of PEG Mw and DMPE-PEG concentration. However, at the critical DMPE-PEG concentration (where mushroom-to-brush conformational transition occurred) maximal magnitude of the effects was reached, which only slightly changed at further DMPE-PEG content and micelle/liposome ratio increase. (C) 2007 Elsevier B.V. All rights reserved.