Hydrodynamic correlations in the translocation of biopolymer through a nanopore: theory and multiscale simulations

TL;DR

This study combines multiscale simulations and theoretical modeling to analyze biopolymer translocation through nanopores, revealing hydrodynamic effects that accelerate translocation and produce a robust power-law scaling of translocation time with polymer length.

Contribution

It introduces a multiscale simulation approach that explicitly includes hydrodynamics and develops a phenomenological model predicting a specific power-law exponent consistent with experiments.

Findings

Hydrodynamic interactions significantly speed up translocation.

The translocation time scales with polymer length as a power law with exponent ~1.2.

Simulation results agree with experimental DNA translocation data.

Abstract

We investigate the process of biopolymer translocation through a narrow pore using a multiscale approach which explicitly accounts for the hydrodynamic interactions of the molecule with the surrounding solvent. The simulations confirm that the coupling of the correlated molecular motion to hydrodynamics results in significant acceleration of the translocation process. Based on these results, we construct a phenomenological model which incorporates the statistical and dynamical features of the translocation process and predicts a power law dependence of the translocation time on the polymer length with an exponent $\alpha$ $\approx 1.2$. The actual value of the exponent from the simulations is $\alpha = 1.28 \pm 0.01$, which is in excellent agreement with experimental measurements of DNA translocation through a nanopore, and is not sensitive to the choice of parameters in the simulation. The mechanism behind the emergence of such a robust exponent is related to the interplay between the longitudinal and transversal dynamics of both translocated and untranslocated segments. The connection to the macroscopic picture involves separating the contributions from the blob shrinking and shifting processes, which are both essential to the translocation dynamics.