Fig. 5.

Sensing of cDNA and protein targets in human serum and urine. a Photon time traces for the detection of cDNA bound to the MB-Carrier in (i) 0.1 M KCl (pH = 8), (ii) 0.1 M KCl + 5% human serum, (iii) and 0.1 M KCl + 10% urine. Conventional confocal single-molecule methods were used (i.e. droplet on a coverslip). b Comparable traces to those shown in (a) using a nanopore. A significant decrease in background fluorescence is observed in part due to the solution being confined to inside the nanopipette. The reservoir outside the nanopipette only contains a 0.1 M KCl buffer solution. Translocation experiments were performed at −300 mV and in all cases, the laser power was 193 ± 6 μW. c Photon and current time traces are shown for the translocation of (i) thrombin in 5% serum, (ii) MB-Carrier in 5% serum, and (iii) MB-Carrier bound to thrombin in 5% serum. The MB-Carrier and thrombin concentration was 30 pM and 1 nM respectively. (iv) Percent synchronisation between the optical and electrical channels for thrombin bound to the MB-Carrier at concentrations ranging from 0.1 to 100 nM. Error bars indicate the standard deviation for data obtained from three different nanopipettes