Figure 2

Time recording of current traces, contour of electric field distribution, and electric field strength. (a) Time recording of current traces recorded at 100, 300, and 600 mV of biased voltages. As a positive voltage was applied across the SiN membrane, a uniform, event-free open-pore current was recorded. The low noise in the baseline measurement allowed reliable identification of current blockages. After addition of protein in the cis reservoir, downward current pulses were observed at 300 and 600 mV. With the increase of voltages, the occurrence frequency of transition events was greatly improved. (b) Contour of electric field distribution of the cylindrical nanopore with a diameter of 60 nm as a function of biased voltages. (c) Electric field strength along the center axis of the pore.