Figure 1.

Schematic illustrations of the microfluidic setup and nanopore detection. (a) Schematic illustration of the microfluidic setup. A nanopore connects two compartments filled with an electrolyte solution (1 M/1 M KCl cis/trans), separated by a silicon nitride membrane. The application of an electric potential difference via two Ag/AgCl electrodes generates an ionic current through the pore. (b) A SEM image of approximately 60-nm nanopore fabricated by FIB, with a scale bar of 100 nm. (c) The schematic conformation of bovine serum albumin (BSA). Serum is a negatively charged globular protein with 583 residues and consists of three domains (I, II, III); the hydrodynamic diameter of the native state is about 10 nm measured with dynamic light scattering at neutral condition.