Manipulation of DNA transport through solid-state nanopores by atomic force microscopy

Abstract

To realize DNA sequencing by a solid-state nanopore, the translocation speed of DNA through the nanopore should be slowed down to obtain the temporal resolution. In this study, we make a nanopore sensing system integrated with an atomic force microscope to control DNA transport through solid-state nanopores. The speed of DNA bound to the probe tip through the nanopore can be controlled by manipulating AFM probe tip, the ionic current as well as the force exerted on DNA strand while it is translocating through the nanopore could be simultaneously measured by the integrated system. The velocity of DNA molecules could be slowed down to ∼100 nm s−1, much less than 1 nt ms−1, which fully meets the requirement for nanopore DNA sequencing. When the probe tip is moving toward or away from the nanopore, obvious current steps associated with force steps are observed during the capturing and releasing processes of DNA strands. All-atom molecular dynamics simulation further validates the observed correlation between the ionic current and dragging force when the DNA is moving through the nanopore.