Fig. 3.

Current–voltage curves of the same nanopore studied in Fig. 2 after modification with 30-nucleotide ssDNA for a 1 M KCl, b 0.1 M KCl and c 10 mM KCl (two sweeps from −4 to +4 V are shown for the DNA-modified nanopore). All recordings were performed at pH 8. Red curves in d present three consecutive reverse sweeps of voltages from +4 to −4 V, showing a big variation between the sweeps and hysteresis compared to the forward sweeps from −4 to +4 V (shown in gray). In 1 and 0.1 M KCl, no differences between currents recorded for forward and reverse voltage sweeps were observed