Electrophoretic Capture of a DNA Chain into a Nanopore

TL;DR

This paper presents a theoretical model of DNA electrophoretic capture into nanopores, revealing different regimes and length dependencies, and suggesting new experimental directions for understanding the process.

Contribution

The paper introduces a steady-state absorption model for DNA capture into nanopores, unifying diffusion-limited and barrier-limited regimes, and predicts novel length dependence behaviors at varying electric fields.

Findings

Capture rate growth is slower for large DNA molecules.

The model reproduces observed regimes and data.

Length dependence can reverse at weak electric fields.

Abstract

Based on our formulation of the DNA electrophoresis near a pore [P. Rowghanian and A. Y. Grosberg, Phys. Rev. E 87, 042723 (2013)], we address the electrophoretic DNA capture into a nanopore as a steady-state process of particle absorption to a sink placed on top of an energy barrier. Reproducing the previously observed diffusion-limited and barrier-limited regimes as two different limits of the particle absorption process and matching the data, our model suggests a slower growth of the capture rate with the DNA length for very large DNA molecules than the previous model, motivating more experiments beyond the current range of electric field and DNA length. At moderately weak electric fields, our model predicts a different effect, stating that the DNA length dependence of the capture rate first disappears as the field is reduced and eventually reverses to a decreasing trend with $N$.