2016/12/27 by Jalal Sarabadani, Timo Ikonen, Sarabadani, Jalal +9 · 1 citation
Engineering · Biochemistry, Genetics and Molecular Biology · #Nanopore and Nanochannel Transport Studies #Fuel Cells and Related Materials #Lipid Membrane Structure and Behavior
paper · pdf · doi:10.48550/arxiv.1612.08590
We study the driven translocation of a semi-flexible polymer through a nanopore by means of a modified version of the iso-flux tension propagation theory (IFTP), and extensive molecular dynamics (MD) simulations. We show that in contrast to fully flexible chains, for semi-flexible polymers with a finite persistence length ℓp the \it trans side friction must be explicitly taken into account to properly describe the translocation process. In addition, the scaling of the end-to-end distance RN as a function of the chain length N must be known. To this end, we first derive a semi-analytic scaling form for RN, which reproduces the limits of a rod, an ideal chain, and an excluded volume chain in the appropriate limits. We then quantitatively characterize the nature of the \it trans side friction based on MD simulations of semi-flexible chains. Augmented with these two factors, the modified IFTP theory shows that there are three main regimes for the scaling of the average translocation time τ∝ Nα. In the stiff chain (rod) limit N/ℓp ≪ 1, α= 2, which continuously crosses over in the regime 1 < N/ℓp < 4 towards the ideal chain behavior with α= 3/2, which is reached in the regime N/ℓp ∼ 102. Finally, in the limit N/ℓp ≫ 106 the translocation exponent approaches its symptotic value 1+ν, where ν is the Flory exponent. Our results are in good agreement with available simulations and experimental data.