nn8b01297_si_002.mpg (14.83 MB)
Spontaneous Transport of Single-Stranded DNA through Graphene–MoS2 Heterostructure Nanopores
media
posted on 2018-04-12, 12:49 authored by Binquan Luan, Ruhong ZhouThe effective transport of a single-stranded
DNA (ssDNA) molecule
through a solid-state nanopore is essential to the future success
of high-throughput and low-cost DNA sequencing. Compatible with current
electric sensing technologies, here, we propose and demonstrate by
molecular dynamics simulations the ssDNA transport through a quasi-two-dimensional
nanopore in a heterostructure stacked together with different 2D materials,
such as graphene and molybdenum disulfide (MoS2). Due to
different chemical potentials, U, of DNA bases on
different 2D materials, it is energetically favorable for a ssDNA
molecule to move from the low-U MoS2 surface
to the high-U graphene surface through a nanopore.
With the proper attraction between the negatively charged phosphate
group in each nucleotide and the positively charged Mo atoms exposed
on the pore surface, the ssDNA molecule can be temporarily seized
and released thereafter through a thermal activation, that is, a slow
and possible nucleotide-by-nucleotide transport. A theoretical formulation
is then developed for the free energy of the ssDNA transiting a heterostructure
nanopore to properly characterize the non-equilibrium stick–slip-like
motion of a ssDNA molecule.