(442c) Understanding Lipid Membrane Interactions with Carbon Nanotubes

Carbon Nanotubes are currently being suggested as nano-needles and nanovectors for delivery of proteins, peptides and genetic materials across cell membranes. The small dimensions of nanotubes and high aspect ratio facilitate delivery with minimal membrane disruption. However, interactions of carbon nanotubes with complex biological structures such as lipid membranes are not completely understood. A fundamental understanding of the mechanisms involved during injection and the magnitude of forces involved in the interaction of membrane and nanotubes is required. We study the forces of interactions between nanotubes and lipid bilayers and also observe the mechanism of internalization of carbon nanotubes by a lipid membrane using Molecular Dynamics (MD). The observed forces provide an insight into the interactions between the nanotube and the membrane lipids and suggest the use of carbon nanotubes as a direct tool to measure the 3D pressure profiles in lipid bilayers. The mechanism of internalization of carbon nanotube by the lipid bilayer was studied by following the free-energy profile, produced using the Jarzynski's equation, as the nanotube traverses the membrane. The obtained free-energy profiles suggested a two stage internalization mechanism that involves both diffusion and an energy dependent process.