Dynamics of C₆₀Molecules in Biological Membranes: Computer Simulation Studies

Abstract

We have performed molecular dynamics simulations of atomistic models of C60 molecules and DMPC bilayer membranes to study the static and dynamic effects of carbon nanoparticles on biological membranes. All four C60-membrane systems were investigated representing dilute and concentrated solutions of C60 residing either inside or outside the membrane. The concentrated C60 molecules in water phase start forming an aggregated cluster. Due to its heavy mass, the cluster tends to adhere on the surface of the bilayer membrane, hindering both translational and rotational diffusion of individual C60. On the other hand, once C60 molecules accumulate inside the membrane, they are well dispersed in the central region of the bilayer membrane. Because of the homogeneous dispersion of C60 inside the membrane, each leaflet is pushed away from the center, making the bilayer membrane thicker. This thickening of the membrane provides more room for both translational and rotational motions of C60 inside the membrane compared to that in the water region. As a result, the dynamics of C60 inside the membrane becomes faster with increasing its concentration.

Advances in The Understanding of Nanomaterial–Biomembrane Interactions and Their Mathematical and Numerical Modeling

“…For instance, Figure 5 illustrates a single fullerene or a cluster of ten fullerenes pen etrating the dioleoylphosphatidylcholine mem brane [97]. The results are consistent with the MD simulations [83], in which the interactions were divided into two segments: the fullerenes lying inside or outside of the membrane. The permeation process of fullerene clusters into the lipid bilayer occurs on a microsecond timescale, which is too large for MD simulations to cap ture.…”

“…The interactions of nine C 60 molecules with the lipid bilayer were simulated to investigate the effect of a C 60 con centrated solution. The results show that C 60 molecules preferred to spread homogeneously near the membrane center when inserted into the membrane [83]. The preferred position, which minimized the potential of mean force, of a C 60 inside a liquid crystalline lipid bilayer was approximately 6-7 Å from the center of the bilayer [84].…”

Fullerene up-take alters bilayer structure and elasticity: A small angle X-ray study

“…Computer simulation studies demonstrated that C 60 may provoke formation of micropores or holes in phospholipid membranes, which then would contribute to membrane leakage (Chang and Lee, 2010;Qiao et al, 2007;Monticelli et al, 2009). Larger aggregates of C 60 adhere on the surface of the bilayer membrane, whereas individual C 60 molecules or small nano-agglomerates can penetrate into the lipid bilayer by means of passive transport through transient micropores in the membrane (Bedrov et al, 2008;Qiao et al, 2007).…”

Effect of Self-Assembly of Fullerene Nano-Particles on Lipid Membrane

“…[12], [22]–[24] They may interact with biomolecules and enter living cells in a different way compared to single fullerene. [25]–[28] So far, the mechanism of the fullerene cytotoxicity is still unclear. Studies on the interaction of the nanoparticles with cell membrane may provide a key to understand the basic questions in nanotoxicology and nanopharmacology.…”

“…On the other hand, computer simulation study is able to provide intuitive results, by ignoring the complexity of cell membrane. [11], [25], [27], [28], [33]–[37] Previous studies have mainly focused on the following aspects: (1) How to improve the water solubility of fullerene and its derivatives by chemical modifications, and thus to reduce its toxicity; [27], [38], [39] (2) Permeation of monomeric fullerene into the lipid bilayer; [25], [26], [28], [34], [40] (3) Interactions between fullerene and water molecules, as well as the interactions among fullerenes. [26], [41]–[44] Nevertheless, the issues of carbon nano-aggregation kinetics and microscopic structure, the invading mechanism of fullerene cluster into the cell membrane, as well as the resulting influence of the aggregate on the lipid membrane are poorly addressed.…”