4 Electrochemistry of Biomimetic Membranes

Abstract

Biological membranes are by far the most important electrified interfaces in living systems. They consist of a bimolecular layer of lipids (the lipid bilayer) incorporating proteins. Lipid molecules are amphiphilic, i.e., consist of a hydrophobic section (the hydrocarbon tail) and a hydrophilic section (the polar head). In biological membranes the two lipid monolayers are oriented with the hydrocarbon tails directed toward each other and the polar heads turned toward the aqueous solutions that bath the two sides of the membrane. The resulting lipid bilayer is a matrix that incorporates different proteins performing a variety of functions. Biomembranes form a highly selective barrier between the inside and the outside of living cells. They are highly insulating to inorganic ions, and large electrochemical potentialdifferences can be maintained across them.