Molecular dynamics simulations reveal single-stranded DNA (ssDNA) forms ordered structures upon adsorbing onto single-walled carbon nanotubes (SWCNT)

Replica exchange molecular dynamics were used to observe the adsorption of single-stranded DNA (ssDNA) onto the surface of single-walled carbon nanotubes (SWCNTs). The assembly of these systems has garnered interest as a method by which SWCNTs can be separated based on chirality. While the exact mechanism of separation is yet unknown, it is hypothesized that the structure of the ssDNA layer pays an important role. Characterization of such an adsorbed layer has been a matter of recent work with the focus being on atomic level detail or such as base-stacking and hydrogen bonding. In this manuscript, we detail a new observation of ssDNA organization and demonstrate how it can be used to infer additional information about the way in which such biopolymers wrap around the cylindrical SWCNT. • Replica exchange simulations are used to assembled ssDNA oligomers on SWCNT surfaces. • Assembly is effected by underlying carbon surface as determined by density plots. • Wrapping angles of ssDNA on SWCNTs can be predicted using geometric relationships.