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Specific Anion and Cation Binding to Lipid Membranes Investigated on a Solid Supported Membrane

2007; American Chemical Society; Volume: 23; Issue: 20 Linguagem: Inglês

10.1021/la701188f

1520-5827

Juan J. García-Celma, Lina Hatahet, Werner Kunz, Klaus Fendler,

Force Microscopy Techniques and Applications

Ion binding to a lipid membrane is studied by application of a rapid solution exchange on a solid supported membrane. The resulting charge displacement is analyzed in terms of the affinity of the applied ions to the lipid surface. We find that chaotropic anions and kosmotropic cations are attracted to the membrane independent of the membrane composition. In particular, the same behavior is found for lipid headgroups bearing no charge, like monoolein. This general trend is modulated by electrostatic interaction of the ions with the lipid headgroup charge. These results cannot be explained with the current models of specific ion interactions.