Fig. 5.

Sensing of protein targets in human serum. a Typical current-time traces are shown for a serial dilution of human serum spiked with 100 mM KCl at applied voltages of −250, 0 and +250 mV. In all cases the serum was inserted inside the nanopipette. As is shown a dilution of 1:20 consists of a sufficiently stable baseline to be used in nanopore sensing. b DNA carrier with 3 TBA probes were incubated in HS with the current-time traces clearly showing sub-peaks associated with thrombin binding at −250 mV. c Similar to Fig. 3, the sub-peaks could easily be distinguished based on location (0.2), (0.7) and (0.9) (N = 94). d Individual current amplitudes for all three sub-peaks, obtained at an applied voltage of −250, −400 and −450 mV with the average current determined via Gaussian fitting. Values after “±” represent 1 standard deviation