ELECTROCHEMICAL STUDY OF THE INTERACTION OF ALKALI AND ALKALINE-EARTHCATIONS WITH A DIBEHENOYL PHOSPHATIDYLCHOLINE MONOLAYER AT THE WATER 1,2-DICHLOROETHANE INTERFACE/

The transfer of alkali and alkaline-earth cations across a dibehenoyl phosphatidyl choline (DBPC) monolayer is analysed by cyclic voltammetr y and capacitance measurements. A cation adsorption process at the pol ar head of the phospholipid was evidenced. After the adsorption an enh ancement of the current or a blocking of the transfer process was prod uced, depending on the nature and cation concentration. This blocking arises as a consequence of the packing induced by Li+ or alkaline-eart h cations adsorption at high concentrations which, in addition, is res ponsible for the destruction of the monolayer at high positive potenti als. Capacitance measurements reinforce this statement. This paper als o illustrates how electrochemical measurements at ITIES are a useful m ethodology for studying cation interactions with lipidic membranes and the transfer processes which occur across them. (C) 1998 Elsevier Sci ence Ltd. All rights reserved.