The electrochemical behavior of zwitterion phospholipid bilayers as determined with the help of membrane potential data, is examined. The synthetic DL-β,γ-dipalmitoyl-α-phosphatidylcoline bilayer shows at 30°C nernstian and sub-nernstian anion responses which depend on the cation present in the electrolytes (LiCl, NaCl, KCl, CsCl, CaCl₂, CeCl₃), and in some cases on the concentration of the solutions considered. On the other hand, nernstian cation responses have been observed in non-isothermal membrane-potential measurements performed on the same lipidic films. These experimental results are explained on the assumption that, from a potentiometric viewpoint the phospholipid membrane behaves as a neutral carrier membrane electrode. Accordingly, the form of the potential equations, and then the anion response of the bilayer, follows from the chemistry of the phospholipid molecules. © 1982.

Export Date: 21 January 2011Source: Scopus