Axial forces at disk surfaces in a cylindrical nanopore

Area of Science:

• Physics
• Nanotechnology
• Physical Chemistry

Background:

• Nanopore-based sensing relies on understanding object translocation physics.
• Accurate simulation of forces is crucial for designing effective nanopore sensors.

Purpose of the Study:

• To dissect the axial forces acting on translocating objects in nanopores.
• To investigate the contributions of Coulombic, dielectric, and fluidic forces.
• To determine the influence of electric fields, ion concentration, and pore properties.

Main Methods:

• Poisson-Nernst-Planck and Navier-Stokes simulations were employed.
• Analysis of forces at disk edges (upper, lower, rim) including Coulomb, dielectric, and fluidic components.
• Calculation of axial total forces and mean axial pressures.

Main Results:

• Axial forces are primarily governed by the external electric field and pore wall charges.
• Dielectric forces significantly oppose Coulombic forces, impacting net axial force.
• Ion concentration affects force amplitudes, while fluidic forces are generally negligible but influenced by pore charges and pressure.
• Larger disks experience greater mean axial pressures.

Conclusions:

• Electric fields and pore charges are dominant factors in nanopore object translocation.
• Nanopore sensor design must account for complex interplay of electrostatic and dielectric forces.
• Simulation insights can guide optimization of nanopore sensors for molecular analysis.