Discrimination of the four kinds of nucleotides by solid-state nanopores using ammonium sulfate aqueous solution

The ionic-current blockades when deoxynucleotide triphosphates(dNTPs) passed through the silicon nitride nanopore were measured. The fabrication of the nanopore by dielectric breakdown and the measurement of the ionic-current through the nanopore were performed in (NH₄)₂SO₄ – KCl – mixed aqueous solution. The standard deviation of the blocked currents when each dNTP was passing through the nanopore was found to decrease compared to that obtained when 100% KCl aqueous solution was used. In addition, the ionic-current blockades derived from the four types of dNTPs passing through the nanopore were clearly discriminated. These results suggest the possibility of the DNA sequencing by solid-state nanopores.