Improved Conductance Blockage Modeling of Cylindrical\nNanopores, from 2D to Thick Membranes

The\nionic current blockage from a nanopore sensor is a fundamental\nmetric for characterizing its dimensions and identifying molecules\ntranslocating through it. Yet, most analytical models predicting the\nconductance of a nanopore in both open and obstructed states remain\ninaccurate. Here, using an oblate spheroidal coordinate framework\nto study the electrical response of nanopore access regions, we reveal\nthat the widely used model from Kowalczyk et al. significantly overestimates\naccess region contributions when blocked by a cylindrical object,\nlike DNA. To address this, we present an improved analytical model\nfor the obstructed access resistance, which we establish as highly\naccurate through finite-element simulations, especially for ultrathin\nmembranes and long narrow channels. Equipped with an improved nanopore\nconductance model, this work provides tools for more accurate calculation\nof the pore size and for the expected blockade from DNA, of high practical\nvalue for many biosensing applications.