Single-Nanopore Investigations with Ion Conductance Microscopy

A three-electrode scanning Ion conductance microscope (SICM) was used to Investigate the local current-voltage properties of a single nanopore. In this experimental configuration, the response measured is a function of changes in the resistances involved in the pathways of ion migration. Single-nanopore membranes utilized in this study were prepared with an epoxy painting procedure to Isolate a single nanopore from a track-etch multipore membrane. Current-voltage responses measured with the SICM probe In the vicinity of a single nanopore were investigated in detail and agreed well with equivalent circuit models proposed in this study. With this modified SICM, the current-voltage responses characterized for the case of a single cylindrical pore and a single conical pore exhibit distinct conductance properties that originate from the geometry of nanopores.