ELECTRICAL PHENOMENA AT THE SURFACES OF PHOSPHOLIPID-MEMBRANES CAUSEDBY THE BINDING OF IONIC COMPOUNDS

Electrical phenomena on the surface of phospholipid membranes caused b y the binding of various ionic compounds (metal ions, lipid-soluble an ions and lipid-soluble cations), have been studied by a direct measure ment method, i.e. the combination of surface potential measurements on the monolayer and zeta potential measurements of lipid vesicles make it possible to estimate the potential profile across the membrane-solu tion interface. The change in the potential profile caused by the bind ing of the various ions revealed the binding locations of these ions. It was found that in the system containing metal ions and lipid-solubl e ions a synergistic effect on the binding existed. Furthermore, the c oagulation behaviour of the lipid vesicles, which is closely related t o the membrane surface potential, is discussed.