Probing nanotube-nanopore interactions.

We demonstrate a new nanoscale system consisting of a nanotube threaded through a nanopore in aqueous solution. Its electrical and mechanical properties are sensitive to experimentally controllable conformational changes on sub-Angstrom length scales. Ionic current transport through a nanopore is significantly suppressed by the threading nanotube and the mechanical interactions between the nanotube and pore are accounted for by a folding geometry. The experiments provide first measurements of the longitudinal resolution and metrology of a solid-state nanopore "microscope." This new nanostructure provides a means to study molecule-nanotube interactions in conducting ionic solutions as well as geometrical and surface properties of nanopores and nanotubes.