Assembly of a Noncovalent DNA Junction on Graphene Sheets and
Electron Transport Characteristics

Single-stranded (ss) DNA readily absorbs on graphene
nanoribons (GNR) due to van der Waals interactions. Such absorption
can be used for a single ssDNA characterization, enabling potential
applications in biotechnology as well as in chemical and biological
sensing. We analyze, using molecular dynamics simulations, the
attachment process of the DNA codon GAG drifted by an external
electric field on a gapped graphene nanoribbon. We calculate the
quantum electron transport through a noncovalent junction GNR−
DNA surrounded by a water monolayer with sodium counterions. We
find that the GNR−DNA junction is stable in aqueous conditions at
room temperature and at 330K. The DNA molecule causes a smooth
transition to the conductive state of the gapped graphene; we estimate
a detectable electronic signal of ∼2 nA, which allows us to identify the DNA molecule bridging the gapped graphene.