Iron Ion and Iron Hydroxide Adsorption to Charge-Neutral Phosphatidylcholine Templates

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• 作者：Wenjie Wang ; Honghu Zhang ; Shuren Feng ; Josue San Emeterio ; Surya Mallapragada ; David Vaknin
• 刊名：Langmuir
• 出版年：2016
• 出版时间：August 2, 2016
• 年：2016
• 卷：32
• 期：30
• 页码：7664-7670
• 全文大小：430K
• 年卷期：0
• ISSN：1520-5827

文摘

Surface-sensitive X-ray scattering and spectroscopy techniques reveal significant adsorption of iron ions and iron-hydroxide (Fe(III)) complexes to a charge-neutral zwitterionic template of phosphatidylcholine (PC). The PC template is formed by a Langmuir monolayer of dipalmitoyl-PC (DPPC) that is spread on the surface of 2 to 40 μM FeCl₃ solutions at physiological levels of KCl (100 mM). At 40 μM of Fe(III) as many as ∼3 iron atoms are associated with each PC group. Grazing incidence X-ray diffraction measurements indicate a significant disruption in the in-plane ordering of DPPC molecules upon iron adsorption. The binding of iron-hydroxide complexes to a neutral PC surface is yet another example of nonelectrostatic, presumably covalent bonding to a charge-neutral organic template. The strong binding and the disruption of in-plane lipid structure has biological implications on the integrity of PC-derived lipid membranes, including those based on sphingomyelin.