Interaction of water-soluble pentaamino acid fullerene derivatives with membranes of phosphatidylcholine liposomes

Regularities of interaction of water-soluble pentaamino acid derivatives of fullerenes (WPDFs) with the lipid bilayer of phosphatidylcholine liposomes were studied using the fluorescent probe method. The studied WPDFs act as quenchers of fluorescence of the hydrophilic probe 2,7-dibromoproflavine in aqueous solutions and in the membranes of phsophatidylcholine liposomes, as well as of the hydrophobic probe pyrene in the phospholipid membrane. The singlet state of the probes is deactivated due to the formation of the long-lived WPDF—probe complex rather than their dynamic interaction. The WPDFs stud- ied were revealed to penetrate into the bilayer membrane of phosphatidylcholine liposomes. The localization of the pentaamino acid fullerene derivatives in the region of polar heads and fatty acid chains of the membrane phospholipids was established on the basis of estimation of the equilibrium constants in the WPDF—probe complexes.