Speaker
Dr
Luca Monticelli
(INSERM Paris, France)
Description
Carbon nanoparticles are biologically active and can enter
easily different kinds of cells. It is not clear how these
materials enter cell membranes and what are the mechanisms
of cell damage. Recently it has been found that natural
organic matter (NOM) interacts strongly with fullerene and
carbon nanotubes, altering their interaction with cells.
Gallic acid is one of the main components of NOM. The
mixture of fullerene and gallic acid can cause cell membrane
damage and cell death by unknown mechanisms [1]. Our goal is
to investigate the molecular interactions between fullerene
and model membranes, in the absence and in the presence of
NOM, and to explore different possible mechanisms of cell
damage, using computer simulations.
We have developed a coarse-grained (CG) model for simple
carbon nanoparticles (fullerenes and nanotubes) compatible
with the MARTINI CG force field for lipids and proteins
[2-4]. Our CG model reproduces reasonably well partitioning
of fullerene between different organic solvents. We use both
unbiased and non-equilibrium MD techniques to characterize
the thermodynamics and the mechanism of permeation of
fullerene clusters through DOPC lipid bilayers. We show that
high fullerene concentrations induce changes in the
structural and elastic properties of the lipid bilayer, but
these are not large enough to cause a direct mechanical
damage to the membrane [5]. In order to study the combined
effect of fullerene and gallic acid on membranes properties,
we use molecular dynamics simulations with an atomistic
representation. Our results suggest that gallic acid
significantly changes the distribution of fullerene and its
interaction with cell membranes. We hypothesize that changes
in the membrane elastic properties could alter membrane
protein functioning and therefore cause cell damage.
[1] E Salonen et al., Small, 4 (2008) 1986.
[2] SJ Marrink et al., J Phys Chem B, 108 (2004) 750.
[3] SJ Marrink et al., J Phys Chem B, 111 (2007) 7812.
[4] L Monticelli et al., J Chem Theory Comput, 4 (2008) 819.
[5] J Wong-ekkabut et al., Nature Nanotech, 3 (2008), 363.
Primary author
Dr
Luca Monticelli
(INSERM Paris, France)
