# DNA Dynamics in Dual Nanopore Tug-of-War

## TL;DR

This study investigates the physics of DNA translocation control in a dual nanopore system, revealing how longer DNA molecules behave in tug-of-war states and how DNA disengages, validated by theoretical models.

## Contribution

It provides new experimental insights into DNA dynamics during tug-of-war in dual nanopores, especially for long DNA, and validates a theoretical first passage model.

## Key findings

- Longer DNA molecules can be trapped with asymmetric partitioning.
- DNA disengagement dynamics depend on pore voltage and DNA size.
- Theoretical predictions match experimental observations.

## Abstract

Solid state nanopores have emerged as powerful tools for single-molecule sensing, yet the rapid uncontrolled translocation of the molecule through the pore remains a key limitation. We have previously demonstrated that an active dual-nanopore system, consisting of two closely spaced pores operated via feedback controlled biasing, shows promise in achieving controlled, slowed-down translocation. Translocation control is achieved via capturing the DNA in a special tug-of-war configuration, whereby opposing electrophoretic forces at each pore are applied to a DNA molecule co-captured at the two pores. Here, we systematically explore translocation physics during DNA tug-of-war focusing on genomically relevant longer dsDNA using a T$_4$-DNA model (166\,kbp). We find that longer molecules can be trapped in tug-of-war states with an asymmetric partitioning of contour between the pores. Secondly, we explore the physics of DNA disengagement from a tug-of-war configuration, focusing on the dynamics of DNA free-end escape, in particular how the free-end velocity depends on pore voltage, DNA size and the presence of additional DNA strands between the pores (i.e. arising in the presence of folded translocation). These findings validate theoretical predictions derived from a first passage model and provide new insight into the physical mechanisms governing molecule disengagement in tug-of-war.