Translocation Dynamics with Attractive Nanopore-Polymer Interactions

Using Langevin dynamics simulations, we investigate the influence of polymer-pore interactions on the dynamics of biopolymer translocation through nanopores. We find that an attractive interaction can significantly change the translocation dynamics. This can be understood by examining the three components of the total translocation time $\tau \approx \tau_1+\tau_2+\tau_3$ corresponding to the initial filling of the pore, transfer of polymer from the \textit{cis} side to the \textit{trans} side, and emptying of the pore, respectively. We find that the dynamics for the last process of emptying of the pore changes from non-activated to activated in nature as the strength of the attractive interaction increases, and $\tau_3$ becomes the dominant contribution to the total translocation time for strong attraction. This leads to a new dependence of $\tau$ as a function of driving force and chain length. Our results are in good agreement with recent experimental findings, and provide a possible explanation for the different scaling behavior observed in solid state nanopores {\it vs.} that for the natural $\alpha$-hemolysin channel.