Translocation of a stiff polymer in a microchannel

Area of Science:

• Polymer Physics
• Nanotechnology
• Biophysics

Background:

• Flexible polymers are typically modeled using stretch elasticity.
• Bend elastic chains exhibit orientation in external fields, such as pore atom anchoring fields.
• Understanding polymer dynamics in nanopores is crucial for applications like DNA sequencing.

Purpose of the Study:

• To investigate the voltage-driven dynamics of stiff polymers translocating through nanopores.
• To analyze the influence of pore wall interactions and electric fields on polymer motion.
• To compare theoretical models with molecular dynamics simulations for DNA translocation.

Main Methods:

• A bend elastic model was employed to describe stiff polymer behavior.
• The Langevin equation of motion was used to calculate the polymer's trajectory.
• Normal mode analysis of the elastic curve with free ends solved the dynamical equation.
• Molecular dynamics simulations were used for comparison with DNA translocation.

Main Results:

• External fields from pore atoms orient the bend elastic chain.
• The electric field within the pore modulates the translocation time.
• Applied forces, like those from optical traps, slow motion and reduce chain response to pore potentials.
• Chain extension along the pore axis is also affected by external forces.

Conclusions:

• Bend elasticity provides a suitable model for stiff polymer translocation through nanopores.
• The interplay between pore geometry, electric fields, and external forces dictates translocation dynamics.
• The model offers insights into DNA translocation through synthetic nanopores, aligning with simulation data.