Concentration Polarization, Surface Charge, and Ionic Current Blockade in Nanopores
Dmitriy V. Melnikov, Zachery K. Hulings, Maria E. Gracheva
Abstract
We elucidate how the concentration polarization, the surface charge densities on the nanopore and nanoparticle, as well as the applied voltage affect the ionic current blockade arising when a nanosized object translocates through a nanopore. We compare our results with self-consistent numerical calculations of the ionic current within the Poisson–Nernst–Planck model to determine their validity. We then apply them to explain the observed trends in the recently measured ionic current traces and extract the surface charge density values for the nanoparticles and nanopores. Our results show that the ionic current is much more sensitive to the passage of small charged objects as compared to the neutral ones of the same size.