Probing the Perturbation of Lecithin Bilayers by Unmodified C₆₀ Fullerenes Using Experimental Methods and Computational Simulations

Abstract

In this study, we aimed to use physicochemical and theoretical tools to understand fundamental problems of the interaction between lipid bilayers (Egg-PC liposomes) and unmodified C 60 fullerenes. The morphology, the size, and the electrokinetic properties of plain and C 60 -loaded liposomes were investigated by means of atomic force microscopy, dynamic light scattering, and ζ-potential studies, respectively. The incorporation of C 60 molecules into the liposomes increases their size; however, there was no effect on their electrokinetic properties. Visualization studies revealed that the presence of C 60 in the membranes induced distortion in vesicle morphology, resulting in nonspherical vesicles. To elucidate further the impact of C 60 molecules on lipid bilayers, we assessed their miscibility by fluorescence spectroscopy measurements. Fluorescence measurements showed that the presence of C 60 in liposomes causes a pronounced effect on the Nile red emission spectrum due to alterations to the packing of the lipid membrane. The release of vesicle-encapsulated calcein was used as a measure of the integrity of the liposomes. Plain liposomes were found to be more stable compared with C 60 -loaded (PC) liposomes, suggesting that C 60 ruptures the liposome membrane. Toxicity studies of C 60 in liposomes were carried out on cultured cells [rodent fibroblasts (3T3)] to assess further their toxicity. The results suggest that fullerene cytotoxic effect was reduced significantly after its incorporation into the liposomal bilayer after 24 h of incubation with the rodent fibroblasts (3T3). Finally, energy minimization studies were employed to underpin the experimental observations. The theoretical calculations show that low concentration of fullerene molecules present in the membrane had no effect on the membrane integrity; however, at high concentrations of fullerenes significant enlargement of the surface area is observed, supporting the experimental findings.

Liposome Formulation of Fullerene-Based Molecular Diagnostic and Therapeutic Agents

“…Experimental findings confirmed the potential of C 60 to reconstruct lipids in biological membranes. Perturbation of lecithin bilayers by unmodified C 60 fullerenes using experimental methods and computational simulations was also carried out [ 26 ]. Physicochemical and theoretical tools were used to understand fundamental problems of the interaction between lipid bilayers (Egg-PC liposomes) and unmodified C 60 fullerenes.…”

Quantification of C60-induced membrane disruption using a quartz crystal microbalance

“…[5][6][7][8][9] The direct contact between nanoparticles (NPs) and cell membranes is suggested to cause cytotoxicity. 10 Therefore both computer simulations [11][12][13][14][15][16] and experimental studies 15,[17][18][19] have been conducted to investigate the interaction between C 60 and cell membranes. C 60 possibly disturbs normal cellular functions via lipid peroxidation, production of reactive oxygen species, 17,18 membrane conformational changes, 11 and membrane disruption.…”

A control of phospholipid motion on graphene layer under external electric field

“…Method for reducing the toxicity of fullerene on the liposomal bilayer was proposed [2]. Therefore the possibility of using a fullerene as the material allows to deliver drugs was installed.…”

“…It is shown in [2] that fullerenes are toxic materials. Method for reducing the toxicity of fullerene on the liposomal bilayer was proposed [2].…”

“…It is shown that fullerenes cause the destabilization of cell membranes. The decrease in the stability of the phospholipid bilayer is observed by increasing the amount of fullerenes in the bilayer of phospholipids [2]. The decrease in the stability of the phospholipid bilayer special is observed when the distance between the fullerenes, located along the bilayer is greater than 0.8 nm [3].…”