Liu Guangming, Fu Li, Zhang Guangzhao
Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, PR China.
J Phys Chem B. 2009 Mar 19;113(11):3365-9. doi: 10.1021/jp810304f.
We have investigated the adsorption of poly(ethylene glycol) (PEG) with different end groups onto phospholipid membranes at the liquid/solid interface by use of a quartz crystal microbalance with dissipation in real time. On a SiO(2)-coated surface, the adsorption of lipid vesicles results in a solid-supported lipid bilayer. Our experiments demonstrate that PEG chains with enough hydrophobic end groups (PEG-C(18)H(37)) can insert in the bilayer and form aggregates on the membrane surface. On the other hand, the adsorbed vesicles are intact on a gold surface. When the end group of PEG chain is not hydrophobic enough, PEG chains do not interact with the vesicles so that they have slight effect on the vesicle stability. However, PEG-C(18)H(37) chains with enough hydrophobic end groups lead to a vesicle-to-bilayer transition because of the insertion of the chains and their aggregation on the membrane surface. In addition, the studies on effect of polymer concentration show that PEG-C(18)H(37) can readily induce the rupture of vesicles at a concentration above the critical micelle concentration.
我们利用具有实时耗散功能的石英晶体微天平，研究了不同端基的聚乙二醇（PEG）在液/固界面上对磷脂膜的吸附情况。在二氧化硅涂层表面，脂质囊泡的吸附形成了固体支撑的脂质双层。我们的实验表明，具有足够疏水端基的PEG链（PEG-C₁₈H₃₇）能够插入双层中并在膜表面形成聚集体。另一方面，吸附的囊泡在金表面保持完整。当PEG链的端基疏水性不足时，PEG链不与囊泡相互作用，因此它们对囊泡稳定性的影响较小。然而，具有足够疏水端基的PEG-C₁₈H₃₇链由于其插入和在膜表面的聚集，导致囊泡向双层转变。此外，对聚合物浓度影响的研究表明，PEG-C₁₈H₃₇在高于临界胶束浓度时能够轻易诱导囊泡破裂。
