Studying DNA translocation in nanocapillaries using single molecule fluorescence

TL;DR

This study combines ionic current detection and fluorescence imaging to analyze DNA translocation through nanocapillaries, providing insights into the process and measuring DNA mobility under high electric fields.

Contribution

It introduces a method for simultaneous ionic and optical measurement of DNA translocation, enabling detailed analysis of molecular motion and mobility in nanocapillaries.

Findings

Verified correspondence between ionic current blockage and DNA passage

Measured effective DNA mobility in nanocapillaries under high electric fields

Demonstrated tracking of DNA motion perpendicular to optical axis

Abstract

We demonstrate simultaneous measurements of DNA translocation into glass nanopores using ionic current detection and fluorescent imaging. We verify the correspondence between the passage of a single DNA molecule through the nanopore and the accompanying characteristic ionic current blockage. By tracking the motion of individual DNA molecules in the nanocapillary perpendicular to the optical axis and using a model, we can extract an effective mobility constant for DNA in our geometry under high electric fields.