Adsorption of Hydrophobic Anions onto Phospholipid Membranes. The Effect of Membrane Surface Charge

Abstract
Hydrophobic adsorption of tetraphenylborate ions (TPB) onto lipid membranes were studied at different pH’s of aqueous phase by using lipid vesicles and monolayers. The amount of adsorbed TPB is much higher at pH 2 than at pH 7.4. This result indicates that the adsorption of hydrophobic ions is affected by the ionization state of surface polar groups of lipids, i.e., that the membrane surface potential plays a role in the adsorption of hydrophobic ions.