Current Flow in a Cylindrical Nanopore with an Object-Implications for Virus Sensing

Area of Science:

• Nanotechnology
• Biophysics
• Sensor Technology

Background:

• Nanopores are emerging as cost-effective, real-time, label-free sensors for virus detection.
• Optimizing nanopore sensor performance requires understanding the influence of various physical parameters on ionic current.

Purpose of the Study:

• To investigate how external electric field, ion concentrations, and pore wall charges affect ionic currents and the relationship between object radius and current in nanopores.
• To provide insights for optimizing nanopore-based virus size sensors.

Main Methods:

• Utilized computational simulations based on the Poisson-Nernst-Planck and Navier-Stokes equations.
• Evaluated the impact of varying external electric field, ion concentrations, and pore wall charge densities on current flow through a charged cylindrical nanopore with a charged disk model.

Main Results:

• Increased external electric field and ion concentrations lead to higher ion currents.
• Current-disk radius relationship is influenced by ion concentration and charge interactions; simple volume exclusion is not a universal explanation for current blockage.
• Pore wall charge density affects ion current magnitude but not its direction relative to charge sign.

Conclusions:

• Nanopore sensor performance is tunable via electric field and ion concentration.
• Understanding charge interactions is crucial for interpreting current changes and accurately sensing virus size.
• Uncharged nanopores show a diminishing current with increasing disk radius, enhancing their utility as virus size sensors.