  Extracting the sequence information of DNA from the blocked ionic current is
the crucial step of the ionic current-based nanopore sequencing approaches. The
thinnest graphene nanopore, which contained only one layer of carbon atoms,
potentially has ultra-high DNA sequencing sensitivity. However, the dynamical
translocation information of DNA contained in the blocked ionic current has not
been well understood to date. In this letter, an assessment to the sensitivity
of ionic current-based graphene nanopore DNA sensing approach was carried out
using molecular dynamics simulations. By filtering the molecular thermal motion
induced noise of ionic current, we found that the instantaneous conformational
variations of DNA in graphene nanopore could be revealed from the fluctuations
of the denoised ionic current. However, the blockage of ionic current which
induced by the proximity of the DNA base-pairs to the nanopore (within 1.5 nm)
was also observed. Although the expected single-base resolution of graphene
nanopore should be enhanced by further studies, our findings indicated that the
ionic current-based graphene nanopore sensing approach has high sensitivity to
the instantaneous translocation status of DNA.
