Dielectric Trapping of Biopolymers Translocating through Insulating Membranes
Department of Physics, Bilkent University, Ankara 06800, Turkey
School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
Interdisciplinary Centre for Mathematical Modelling and Department of Mathematical Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
Department of Applied Physics and QTF Center of Excellence, Aalto University School of Science, P.O. Box 11000, FI-00076 Aalto, Espoo, Finland
Author to whom correspondence should be addressed.
Received: 15 October 2018 / Revised: 4 November 2018 / Accepted: 6 November 2018 / Published: 9 November 2018
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Sensitive sequencing of biopolymers by nanopore-based translocation techniques requires an extension of the time spent by the molecule in the pore. We develop an electrostatic theory of polymer translocation to show that the translocation time can be extended via the dielectric trapping of the polymer. In dilute salt conditions, the dielectric contrast between the low permittivity membrane and large permittivity solvent gives rise to attractive interactions between the
portions of the polymer. This self-attraction acts as a dielectric trap that can enhance the translocation time by orders of magnitude. We also find that electrostatic interactions result in the piecewise scaling of the translocation time
with the polymer length L
. In the short polymer regime
nm where the external drift force dominates electrostatic polymer interactions, the translocation is characterized by the drift behavior
. In the intermediate length regime
is the Debye–Hückel screening parameter, the dielectric trap takes over the drift force. As a result, increasing polymer length leads to quasi-exponential growth of the translocation time. Finally, in the regime of long polymers
where salt screening leads to the saturation of the dielectric trap, the translocation time grows linearly as
. This strong departure from the drift behavior highlights the essential role played by electrostatic interactions in polymer translocation.
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MDPI and ACS Style
Buyukdagli, S.; Sarabadani, J.; Ala-Nissila, T. Dielectric Trapping of Biopolymers Translocating through Insulating Membranes. Polymers 2018, 10, 1242.
Buyukdagli S, Sarabadani J, Ala-Nissila T. Dielectric Trapping of Biopolymers Translocating through Insulating Membranes. Polymers. 2018; 10(11):1242.
Buyukdagli, Sahin; Sarabadani, Jalal; Ala-Nissila, Tapio. 2018. "Dielectric Trapping of Biopolymers Translocating through Insulating Membranes." Polymers 10, no. 11: 1242.
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