Ion-induced interfacial dynamics of phospholipid monolayers.
Ion-induced interfacial dynamics of phospholipid monolayers were studied by various electrochemical techniques. The lipid monolayers were constructed by using the mercapto derivatives of natural lipids that were self-assembled directly onto gold electrode surfaces in a tails-down fashion. The supported lipid assemblies appeared to act as rather effective electron-tunneling barriers with K3Fe(CN)6 as the redox probe, despite a relatively low surface coverage and/or a disordered surface structure. Upon the stimulation by alkaline-earth ions, the lipid layers appeared to undergo surface reorganization, exposing part of the electrode surface which resulted in the formation of microscopic mass-transfer lipid channels. The dimensions and/or the number of these channels increased with increasing ion concentrations, and this ion-gate effect appeared to be quite selective, with the most pronounced effects observed among the series of alkaline-earth ions with Ca2+.
Chen
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S
Department of Chemistry, Southern Illinois University, Carbondale 62901-4409, USA. schen@chem.siu.edu
Huang
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K
D004563:Electrochemistry; D008567:Membranes, Artificial; D010743:Phospholipids / Q000138:chemical synthesis / Q000737:chemistry*
D008567:Membranes, Artificial; D010743:Phospholipids