Experimental evidence for the interaction of C-60 fullerene with lipid vesicle membranes

There are some molecular dynamic simulations but a paucity of experimental evidence of the effects of C-60 fullerene on lipid bilayers. The aim of this study is to assess the potential for disruption of the lipid bilayer by C-60 suspended in water. We selected a C-60 suspension that has previously been shown to provoke cell membrane destabilisation in vivo. Electromobility measurements show significant negative surface charge on the C-60 nanoparticles suspended in a glucose solution and a zeta potential of -26 mV. The prevalent C-60 clusters have hydrodynamic radii of approximately 2 nm. Phase contrast microscopy and computer aided image analysis results show that C-60 causes shape transformations and rupture of unilamellar phospholipid vesicles, indicative of changes in their average mean curvature. Small-angle X-ray scattering reveals that C-60 provokes disruptions of external membranes of multilamellar vesicles only after freeze and thaw cycles. Here, the liposomes undergo breakage and annealing steps which increase the probability for fullerenes to insert into the MLVs. Our experimental findings confirm the potential of C-60 to reconstruct lipids in biological membranes. This research enhances our understanding of the impact of engineered nanoparticles on cell membranes. (C) 2011 Elsevier Ltd. All rights reserved.