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Topological jamming of spontaneously knotted polyelectrolyte chains driven through a nanopore
A Rosa1, M Di Ventra, C Micheletti
1SISSA-Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, 34136 Trieste, Italy. anrosa@sissa.it
Physical Review Letters
|September 26, 2012
Summary
Knots in polyelectrolyte chains do not jam nanopore translocation but increase friction with applied force, potentially halting the process. This finding is crucial for applications like DNA sequencing.
Area of Science:
- Physics
- Materials Science
- Biophysics
Background:
- Solid-state nanodevices enable studying polyelectrolyte chains via nanopore translocation.
- Previous studies focused on unknotted chains, neglecting topological defects.
Purpose of the Study:
- To investigate the impact of chain knots on the electrophoretic translocation through nanopores.
- To understand how topological defects influence polymer dynamics in confined geometries.
Main Methods:
- Brownian dynamics simulations were employed.
- A coarse-grained polyelectrolyte model was utilized.
- Simulations analyzed translocation dynamics under varying forces.
Main Results:
- Knots do not inherently jam the translocation process.
- Knots introduce an effective friction that escalates with applied force.
- Translocation is significantly hindered above a critical force threshold.
Conclusions:
- Topological knots in polyelectrolyte chains present a force-dependent friction, not a complete blockage.
- This dynamical crossover has implications for nanopore-based technologies, including DNA sequencing.
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