Interaction of fullerenes C60 with large unilamellar vesicles

In order to explore the fullerene-lipid interaction, we have studied the effects caused by C60 on Large Unilamellar Vesicles (LUV). For this purpose liposomes composed of L-a Phosphatidylcholine (PC) and 1,2-dimyristoyl-sn-glycero-3-phospocholine (DMPC) and Cholesterol (Chol) in 2:1 molar ratio were used. The dispersions were characterized by means of Dynamic Light Scattering (DLS), zeta-potential measurements and Differential Scanning Calorimetry studies (DSC). The incorporation of C60 into liposomes altered their physicochemical properties. A reduction to the mean diameter of the liposomes was observed when C60 were incorporated, which might imply deformations on the lipid membrane induced by fullerenes. An increase to the surface charge of the liposomes was noticed when C60 molecules were present in the membrane providing evidence of their successful incorporation into the liposomal bilayers. Finally the miscibility of liposomes with C60 was investigated by DSC. Alterations occurred to the main transition of the liposomes when C60 molecules were present in the membrane might be attributed to the penetration of the carbonaceous material into the lipid bilayers.