Simulation and Analysis of Ion Detection in DNA Nanopore FET Device

Abstract

In this work, a novel ion detection device integrating a DNA-origami nanopore with a field-effect transistor (FET) was designed and modeled to determine the sensitivity of the device within cellular environments. The design employed an "artificial gap junction" constructed using a DNA origami nanopore as a direct interface between the cell and the device. The DNA-origami structure is bio-compatible and can convert signals generated by ionic currents directly into electrical signals by detecting the ions as a buildup of charge. An electrical double layer would form on the nanopore inner wall and over the gate oxide, and the resulting source-drain current can be used to measure the presence of ions in the cell. The electric double layer theory was studied and applied to model ion and potential distributions inside the DNA nanopore. The device combined with the nanopore is shown to have high sensitivity to ion concentration, with the electrical double layer behavior governing the device characteristics. A logarithmic relationship was found between ion concentration and a single FET current, generating up to 200nA of current difference with a small applied bias.