Mar 23 – 24, 2009
KTH - Royal Institute of Technology
Europe/Stockholm timezone

Molecular dynamics simulations of the interactions of carbon nanotubes with biomolecules

Mar 23, 2009, 11:00 AM
45m
F3 (KTH - Royal Institute of Technology)

F3

KTH - Royal Institute of Technology

Lindstedtsväg 26

Speaker

Dr Jayne Wallace (University of Oxford, UK)

Description

There is great interest in exploiting the novel properties of carbon nanotubes (CNTs) for use in biology and medicine. For example, CNTs have potential application in drug delivery, cancer and gene therapy, and as components of biosensors. However, prior to their usage we need to both develop methods to overcome the hydrophobicity-induced aggregation of CNTs, and also to understand the fundamental interactions of CNTs with cellular components. Dissolution of CNTs has been facilitated by the noncovalent adsorption of both lipids and detergents onto the surface of CNTs. We investigate the interaction of both lipids and detergents with single-walled CNTs via coarse-grained molecular dynamics [1,2]. We present evidence that the mechanism of adsorption of these amphiphiles onto a CNT is dependent upon amphiphile concentration. Furthermore, the chirality of the CNT influences the amphiphile wrapping angle for low amphiphile concentration. Recently, designed synthetic peptides have also proven effective at dispersing CNTs. This approach has the significant advantage that the nature of the peptides coating the CNTs can be controlled by specifying the amino acid sequence. Hence, peptides can be designed such that the peptide/CNT complex may target specific tissue. One such designed synthetic peptide, nano-1 [3], folds into an amphiphilic α-helix in the presence of CNTs and leads to CNT dispersion. We implement molecular dynamics to investigate the self-assembly of nano-1 onto CNTs, using both a coarse-grained and atomistic approach. Using this multi-scaled method, we show that nano-1 interacts with CNTs in a preferential orientation. Furthermore, the charged surfaces of nano-1 facilitate inter-peptide interactions within the peptide/CNT complex, promoting helix stability. We have also performed coarse-grained molecular dynamics simulations of CNTs penetrating through lipid bilayers [4]. This work is motivated by the use of CNTs as nanoinjectors. We show that CNTs extract lipids from the bilayer upon penetration. These lipids interact with both the inner and outer CNT surface, with lipids in the CNT interior potentially “blocking” the tube. [1] Wallace, E. J.; Sansom, M. S. P. Nano Lett. 2007, 7, 1923-1928. [2] Wallace, E. J.; Sansom, M. S. P. Nanotechnology 2009, 20, 045101. [3] Dieckmann, G. R.; Dalton, A. B.; Johnson, P. A.; Razal, J.; Chen, J.; Giordano, G. M.; Munoz, E.; Musselman, I. H.; Baughman, R. H.; Draper, R. K. J. Am. Chem. Soc. 2003, 125, 1770-1777. [4] Wallace, E. J.; Sansom, M. S. P. Nano Lett. 2008, 8, 2751-2756.

Primary author

Dr Jayne Wallace (University of Oxford, UK)

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