Analysis of High Aspect Ratio Nanopores for Resistive Pulse Sensing Applications Through Numerical Simulations

Microfluidic devices form a class of microelectro mechanical systems used for the manipulation of fluid volumes in the order of micro-and nanoliters. These devices find application in health and environmental sciences for the detection of biomolecules. One long-standing detection principle is resistive pulse sensing (RPS) which has been adapted to the sub-micrometer scale. The key element in RPS is the nanopore by which the electric current is monitored. Pulses in the electric current are formed upon the translocation of particles through the nanopore. Different technologies can be used to create these nanopores, but the material and the aspect ratio impose limitations. In this study, the focused ion beam technology was used to create a high-aspect-ratio nanopore in a multi-layer-duo-material membrane. We used the data to develop a new 2D numerical model to study the pore geometry and investigate irregularities in its shape. Impedance frequency analysis results show the sensitivity of this method to differentiate among high similar geometries.