The improvement of signal-to-noise ratio by solid-state nanopores using a salt gradient

Abstract

Solid-state nanopore is widely used as detector to analyze individual unlabeled DNA molecules in solutions. The small scale of nanopore(d<5nm) is of the capability to obtain high signal-to-noise ratio information, but its most drawback is that this kind of nanopore is easily blocked during the molecules thread into the pore. At the same time, it is extremely difficult to be manufactured. Although the large diameter nanopore is not easily blocked and the fabricating cost is less, it is also hard to achieve efficient signal. In this paper, we find a solution which can enhance the signal-to-noise ratio for large scale nanopores—when the cis reservoir concentration is fixed at 1 M KCl, amplitude of the ionic current decrease is significantly enhanced with the trans reservoir concentration changing from 1 M KCl to 0.1 M KCl. So it is efficient to distinguish different kind of molecules and enhance the signal-to-noise ratio, thereby advancing the possibility of analyzing DNA samples using nanopores.