Polymer translocation into a fluidic channel through a nanopore

TL;DR

This study uses Langevin dynamics simulations to explore how polymer translocation into a fluidic channel through a nanopore is affected by crowding and confinement, revealing nonuniversal scaling behaviors.

Contribution

It introduces a detailed analysis of polymer translocation dynamics under confinement, highlighting the impact of crowding and channel width on translocation time scaling.

Findings

Translocation time $ au$ depends nonuniversally on chain length $N$ and channel width $R$.

Scaling exponent $eta$ of $ au$ with $N$ varies with $R$.

Inverse linear dependence of $ au$ on force $F$ breaks down, showing a minimum of $eta$ as a function of $F$.

Abstract

Using two dimensional Langevin dynamics simulations, we investigate the dynamics of polymer translocation into a fluidic channel with diameter $R$ through a nanopore under a driving force $F$. Due to the crowding effect induced by the partially translocated monomers, the translocation dynamics is significantly altered in comparison to an unconfined environment, namely, we observe a nonuniversal dependence of the translocation time $\tau$ on the chain length $N$. $\tau$ initially decreases rapidly and then saturates with increasing $R$, and a dependence of the scaling exponent $\alpha$ of $\tau$ with $N$ on the channel width $R$ is observed. The otherwise inverse linear scaling of $\tau$ with $F$ breaks down and we observe a minimum of $\alpha$ as a function of $F$. These behaviors are interpreted in terms of the waiting time of an individual segment passing through the pore during translocation.