Translocation of Hydrophobic Polyelectrolytes under Electrical Field: Molecular Dynamics Study

Area of Science:

• Polymer physics
• Computational biophysics
• Soft matter science

Background:

• Polyelectrolyte (PE) chain translocation through nanopores is crucial for biological processes and nanotechnology.
• Understanding the factors influencing translocation dynamics, such as electric fields and solvent conditions, is essential.

Purpose of the Study:

• To investigate the translocation dynamics of polyelectrolyte chains driven by an electric field through a realistic pore.
• To quantitatively study the interplay between translocation and globule unraveling under various solvent conditions.

Main Methods:

• Molecular dynamics (MD) simulations using a coarse-grained HP model.
• Mimicking high salt conditions and incorporating realistic force fields within the pore.
• Analyzing translocation dynamics, waiting times, and drift times.

Main Results:

• Polyelectrolyte chains in globular form unfolded to translocate through the pore under an electric field.
• Translocation time was minimized in slightly poor solvent conditions, with minimal variation at medium hydrophobicity.
• Dynamics were governed by both pore friction and internal friction from globule uncoiling.

Conclusions:

• Solvent conditions significantly impact polyelectrolyte translocation dynamics.
• Internal friction due to globule uncoiling plays a critical role alongside external friction.
• Simulation results provide insights comparable to simplified Fokker-Planck models.