Computational Modeling of Ionic Currents Through Difform Graphene Nanopores with Consistent Cross-sectional Area
Understanding the mechanism of ion transport and the related ionic current through a nanopore is significant for improving the sensing accuracy of biophysical and diagnostic applications using nanopore technology. Here, systematic theoretical studies of ionic current dependence on the geometry of a nanopore were performed. It is surprisingly found that the ionic current through a nanopore with a smaller perimeter is obviously larger than that with a larger perimeter though all the nanopores have a consistent cross-sectional area, which is also found for nanopores with different hydrophobicity. This interesting result originates from the reduction of ion concentration, mobility and conductivity in proximity to the nanopore surface. Besides, an obvious ionic current enhancement was observed for hydrophobic nanopores compared to hydrophilic ones which is caused by the increased ion mobility through hydrophobic nanopores. A simple model that combines the distribution of ion conductivity as well as traditional Ohm’s law was successfully applied to predict ionic current through difform nanopores with different hydrophobicity. This work here helps to develop high-resolution nanopore sensors in the near future.