Translocation of an Active Polymer into a Circular Cavity

TL;DR

This study investigates the translocation dynamics of an active semi-flexible polymer into a circular cavity using Langevin dynamics simulations, revealing how cavity size and force influence translocation time and polymer configuration.

Contribution

It provides new insights into the force scaling behavior and polymer packing configurations during active polymer translocation into a circular cavity.

Findings

Force exponent $eta$ varies with cavity size, being -1 for small R and approximately -0.92 for large R.

Translocation time scales with self-propelling force as $ au o F_{sp}^{eta}$.

Polymer configurations are more regular at small R and high force.

Abstract

Translocation dynamics of an active semi-flexible polymer through a nano-pore into a rigid two dimensional circular cavity, and the polymer packing dynamics have been studied by using Langevin dynamics (LD) simulations. The results show that the force exponent $\beta$, for regime of small cavity radius, i.e. $R \ll R_{\textrm{g}}$, where $R_{\textrm{g}}$ is the gyration radius of the passive semi-flexible polymer in two dimensional free space, is $\beta=-1$, while for large values of $R \gg R_{\textrm{g}}$ the asymptotic value of the force exponent is $\beta \approx -0.92$. The force exponent is defined by the scaling form of the average translocation time $\langle \tau \rangle \propto F_{\textrm{sp}}^{\beta}$, where $F_{\textrm{sp}}$ is the self-propelling force. Moreover, using the definition of the turning number for the polymer inside the cavity, it has been found that at the end of translocation process for small value of $R$ and in the strong force limit the polymer configuration is more regular than the case in which the value of $R$ is large or the force is weak.