[18a-222-1~11] 12.6 Nanobiotechnology

[18a-222-2] Low-frequency noise reduction with solid-state nanopores by preventing surface charge fluctuation

〇KAZUMA MATSUI¹, YUSUKE GOTO¹, RENA AKAHORI¹, MICHIRU FUJIOKA², TAKESHI ISHIDA¹, ITARU YANAGI¹, TAKAHIDE YOKOI¹, KEN-ICHI TAKEDA¹ (1.R&D Group, Hitachi Ltd., 2.Hitachi High-Tech. Ltd.)

Keywords:DNA sequencing, Nanopore, Low-frequency noise

To realize DNA sequencing with solid-state nanopore, reduction of an ionic current noise is an important issue. Especially, low-frequency noise causes a serious problem for reducing read accuracy of DNA sequencing. Ever since the discovery of the noise more than 20 years ago, its origins have been heavily debated, but it has not yet clarified. An effective method for the noise reduction is not also established. In this research, we identify a new origin of the noise due to an exchange reaction of metal ions on a nanopore wall surface. With various metal ions (Li, Na, K, Rb, Cs, Mg, Ca), its low-frequency noise coefficient C_lf, which is the magnitude of the low-frequency noise, was compared. We verified our hypothesis from the relationship between C_lf and the affinities of the cations to silicon oxide group on the surface. We also established a new noise reduction method by pre-wetting a nanopore with a solution containing divalent cations to prevent the absorption of other cations.