(479b) Self Assembly of DNA Segments On Graphene and Carbon Nanotube Surfaces in Aqueous Environment: a Molecular Simulation Study

Molecular dynamics simulations were performed to study the interaction of double stranded DNA segments with the surfaces of graphene and carbon nanotubes in aqueous solution. Three different kinds of self assembly phenomena were observed. Firstly, it is found that a DNA segment can `stand up' on the carbon surfaces with its helix axis perpendicular to the surfaces of graphene or nanotube. Secondly, a DNA segment can also lie on the carbon surface with its axis parallel to the surface, if both of its ends can manage to interact with the carbon surfaces. In this case, the ending basepairs of the DNA are broken due to severe deformations. Thirdly, it is observed that short DNA segments can concatenate to each other to form a longer DNA when they are placed in the grooves of nanotube bundles. The self assembly usually happens in less than 10 nanoseconds. The very fast self assembly of DNA segments on carbonaceous surfaces emphasizes the dominant role of hydrophobic forces in DNA-carbon interaction in aqueous environment.