Driven polymer translocation through a nano-pore

Dr. Jalal Sarabadani (Aalto University, Helsink)
Monday, 94/02/28 (May 19, 2015) 15:30

Abstract
In this talk, we are going to investigate the dynamics of pore-driven polymer translocation mainly by using analytical model and also by molecular dynamics (MD) simulations [1]. By using the tension propagation theory [2] within the constant flux approximation [3] an explicit equation of motion for the tension front is derived. This equation leads us to a scaling relation for the average translocation time, \tau, which captures the asymptotic result \tau ~ N_0^{1+\nu}. Here, N_0 is the chain length and \nu is the Flory exponent. Moreover, we derive the leading correction-to-scaling term to \tau which is a finite chain length correction term due to the effective pore friction. This correction term is linearly proportional to N_0 [4]. Then by incorporating the fluctuations in the initial configuration of the polymer chain into the model in addition to thermal noise, the model not only reproduces previously known results but also considerably improves the estimates of the monomer waiting time distribution and the time evolution of the translocation coordinate s(t), showing excellent agreement with MD simulations [5,6]. We also discuss the effect of a flickering pore and an alternating external driving force on the translocation time using the new model [7].

[1] J. Sarabadani, T. Ikonen and T. Ala-Nissila, J. Chem. Phys. 141, 214907 (2014).
[2] T. Sakaue, Phys. Rev. E 76, 021803 (2007).
[3] P. Rowghanian and A. Y. Grosberg, J. Phys. Chem. B 115, 14127 (2011).
[4] T. Ikonen, A. Bhattacharya, T. Ala-Nissila and W. Sung, Europhys. Lett. 103, 38001 (2013).
[5] T. Ikonen, A. Bhattacharya, T. Ala-Nissila and W. Sung, Phys. Rev. E 85, 051803 (2012).
[6] T. Ikonen, A. Bhattacharya, T. Ala-Nissila and W. Sung, J. Chem. Phys. 137, 085101 (2012).
[7] J. Sarabadani, T. Ikonen and T. Ala-Nissila, Polymer translocation through a flickering pore under an alternating driving force, to be submitted.