Polyetylenimine (PEI) adsorption to a DMPG lipid-monolayer in the presence of iron salts and EDTA
Polyetylenimine (PEI) adsorption to a DMPG lipid-monolayer in the presence of iron salts and EDTA
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DOI：
10.1016/j.polymer.2016.08.034
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发表时间：
2016-10
期刊：
影响因子：
4.6
通讯作者：
Andreas Gröning;H. Ahrens;T. Ortmann;F. Lawrenz;C. Helm
中科院分区：
文献类型：
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作者：
Andreas Gröning;H. Ahrens;T. Ortmann;F. Lawrenz;C. Helm
支化PEI从2 mmol/L的溶液中吸附到带负电荷的DMPG单分子层上，在空气/水界面处从含有2 mmol/L FeSO 4的溶液中。利用X射线反射率，发现吸附的PEI层含有铁。与从清洁水中吸附的PEI相比，厚度增加了三到四倍。当PEI溶液中EDTA的含量大于铁离子的含量时，PEI吸附层的表面覆盖率和厚度增加了7倍。PEI层含有静电结合的Fe（EDTA）2−络合物。当脂质经历从液体膨胀（LE）到液体冷凝（LC）相的相变时，吸附的聚合物层的厚度和表面覆盖度增加。LC相用掠入射X射线衍射（GIXD）表征。用布鲁斯特角显微镜观察了液晶畴的形成和生长。然而，畴的最大面积分数为65%。如果单层是高度压缩，我们得出结论，布鲁斯特角显微镜图像横向不均匀的聚合物层。
Branched PEI is adsorbed from 2 mmol/L solution onto a negatively charged DMPG monolayer at the air/water interface from a solution with 2 mmol/L FeSO4. With X-ray reflectivity it is found that the adsorbed PEI layer contains iron. Compared to PEI adsorbed from clean water the thickness is increased by a factor three to four. It is suggested that cooperative bonds stabilize iron ions within the PEI layer.When the PEI solution contains more EDTA than iron ions, the surface coverage and the thickness of the adsorbed PEI layer is increased by a factor seven. The PEI layer contains electrostatically bound Fe(EDTA)2−complexes. The thickness and the surface coverage of the adsorbed polymer layer increase when the lipids undergo a phase transition from the liquid expanded (LE) to the liquid condensed (LC) phase. The LC phase is characterized with Grazing Incidence X-ray Diffraction (GIXD). With Brewster Angle Microscopy the formation and growth of LC domains is observed. However, the maximum area fraction of domains is 65%. If the monolayer is highly compressed, we conclude that Brewster Angle Microscopy images a laterally inhomogeneous polymer layer.