Uptake of iron (III)-ethylenediamine-N, N, N′, N′-tetraacetic acid complex by phosphatidylcholine lipid film. Part II. Effect of film curvature. (January 2018)

• Record Type: Journal Article
• Authors: Villeneuve, Masumi; Tanaka, Mihoko; Saito, Natsumi; Sakamoto, Hiroyasu; Hayami, Yoshiteru
• Is Part Of: Chemistry and physics of lipids. Volume 210(2018)
• Page Start: 14
• Page End: 21
• Publication Date: 2018-01
• Subjects: Phosphatidylcholine -- Metal complex -- Micelle -- pH effect -- Curvature effect -- Molecular interaction; Lipids -- Periodicals; Lipids -- Periodicals; Lipides -- Périodiques; Lipids; Periodicals; Electronic journals; 547.77
• DOI: 10.1016/j.chemphyslip.2017.12.001
• Languages: English
• ISSNs: 0009-3084

Abstract

Graphical abstract: Highlights: A 3-solute micelle solution with a polyprotic acid is analyzed thermodynamically. Uptake of Fe-EDTA by phosphatidylcholine lipid micelle is quantitatively evaluated. Substantial amount of Fe-EDTA is incorporated in lipid micelles at low pH. A planar film holds more Fe-EDTA than a film with positive curvatures. Abstract: Mixed micelles formed in a ternary-solute aqueous solution of NaOH, iron (III)-ethylenediamine- N, N, N ′, N ′-tetraacetic acid complex (Fe-EDTA) and 1, 2-diheptanoyl- sn -glycero-3-phosphatidyl choline (DHPC) were studied and compared with the mixed adsorbed film reported in Part I of this series to clarify the effect of the curvature of molecular assemblies on the interactions between their Fe-EDTA and DHPC constituents. The critical micelle concentrations (CMCs), surface tension at the CMC, and solution pH were measured as functions of the mole fractions of NaOH and DHPC. Rigorous thermodynamic equations were derived, in which the overall proton dissociation equilibria of Fe-EDTA and DHPC were taken into consideration, and applied to experimental data to obtain phase diagrams of micelle formation and the micelle-adsorbed film equilibrium. It was found that when the bulk solution was strongly acidic, Fe-EDTA was incorporated in the micelles. However, the adsorbed film was more Fe-EDTA-enriched than the micelle. These findings imply that a flat cell membrane is more permeable to an iron complex than a cell membrane with positive curvature.