DNA adsorption on graphene

Journal Article

Here we use classical applied mathematical modeling to determine surface bind

ing energies between single-strand and double-strand DNA molecules interacting

with a graphene sheet. We adopt basic mechanical principles to exploit the 6-12

Lennard-Jones potential function and the continuum approximation, which assumes

that intermolecular interactions can be approximated by average atomic line or sur

face densities. The minimum binding energy occurs when the single-strand DNA molecule is centred 20.2 ˚A from the surface of the graphene and the double-strand DNA molecule is centred 20.3 ˚A from the surface, noting that these close values apply for the case when the axis of the helix is perpendicular to the surface of

graphene. For the case when the axis of the helix is parallel to the surface, the

minimum binding energy occurs when the axis of the single-strand molecule is 8.3 ˚ A from the surface, and the double-strand molecule has axis 13.3 ˚A from the sur

face. For arbitrary tilted axis, we determine the optimal angles Ω of the axis of

the helix, which give the minimum values of the binding energies, and we observe that the optimal rotational angles tend to occur in the intervals Ω ∈ (π/4,π/2) and

Ω ∈ (π/7,π/5) for the single and double-strand DNA molecules, respectively.