[18p-E203-1~16] 12.6 Nanobiotechnology

[18p-E203-8] Silicon nitride nanopore created by dielectric breakdown with a divalent cation:
Deceleration of translocation speed and identification of single nucleotides

〇Yusuke Goto¹, Matsui Kazuma¹, Yanagi Itaru¹, Takeda Ken-ichi¹ (1.Hitachi R&D)

Keywords:nanopore, DNA sequencer, Controlled dielectric breakdown

Nanopore DNA sequencing with a solid-state nanopore requires deceleration of the ultrafast translocation speed of single-stranded DNA. We report an unexpected phenomenon: controlled dielectric breakdown (CBD) with a divalent metal cation, especially Ca²⁺, provides a silicon nitride nanopore with the capability of decelerating DNA speed down to 100 μs/base even after solution replacement. This speed is two orders of magnitude slower than that for CBD with a conventional monovalent metal cation. This slowing effect strongly depends on temperature, and only a 40 °C temperature drop induces further deceleration of DNA speed down to 7300 μs/base. The slowing effect originates from the strong interaction between DNA and divalent cations, which were coated on the sidewall of the nanopore during the CBD process. In addition, we found that a nanopore created via CBD with Ca²⁺ can decelerate the speed of even single nucleotide monomers, dNMPs, down to 0.1 - 10 ms/base. The four single nucleotides could be statistically identified according to their blockade currents.