Determination of the optimal nanotube radius for single-strand DNA encapsulation

Journal Article

We model the molecular interactions between a single-strand DNA molecule and

a carbon nanotube to determine the suction force experienced by the DNA which

is assumed to be located on the axis near the open end of a single-walled carbon

nanotube. We determine the optimal nanotube radius for encapsulation, that is the

radius of nanotube with the lowest interaction energy. The expression for the molec

ular interaction energy is derived from the 6-12 Lennard-Jones potential together

with the continuum approach, which assumes that a discrete atomic structure can

be replaced by a line or surface with constant average atomic density. We find that

a single-strand DNA can be encapsulated inside a single-walled carbon nanotube with a radius larger than 8.2 ˚A, and we show that the optimal single-walled carbon nanotube needed to fully enclose the DNA molecule has radius 8.8 ˚A, which ap

proximately corresponds to the chiral vector numbers (13, 13). This means that if

we wish to encapsulate single-strand DNA into a carbon nanotube, an ideal single

walled carbon nanotube to do this is (13, 13) which has the required radius of 8.8 ˚ A.