Figure 4.

Voltage gating of the nanopore. (A) I–V characterization of the nanopore–FET before and after gold deposition and (B) after gold deposition at varying V_gate. (C) Variation of nanopore surface charge with gating potentials (V_gate) was probed by differential capacitance measurements on an ultramicro-gold-deposited electrode, showing a capacitance minimum at −100 mV, which is attributed to the potential of zero charge (pzc). (D) This correlates well with the gating of 10 kbp DNA in 100 mM KCl, 10 mM Tris–HCl, and 1 mM ethylenediaminetetraacetic acid (EDTA) buffer at pH 8. DNA transport could be switched off or on depending on whether the potential applied to V_gate was above or below the pzc. By controlling the gate potential, translocations can be switched on and off in real time as shown in (E).