Modeling the Effective Conductance Drop Due to a Particle in a Solid State Nanopore Towards Optimized Design

An understanding of the current change in a solid state nanopore due to particle movement or capture is crucial for improvement of nanopore based sensing technologies. For lower aspect ratio pores, which are gaining importance due to their high sensitivity, there is interplay between access and pore resistance and the existing theories for computation of access resistance cannot explain most of the experimental observations. Hence, there is a need to develop a comprehensive model for calculating the effective conductance drop in presence of particles in a solid state nanopore. In this paper, we develop analytical models to calculate both the access and pore resistance in presence of particle at different positions during translocation and also when captured by receptors in functionalized nanopores. A wide range of pore geometry and molar strength has been investigated. Taking into consideration the positional uncertainty during particle translocation, the effective resistance sensitivity has been found to agree very well with the experimental observations in low aspect ratio pore. Additionally, we observe that in functionalized nanopores, a pore of higher diameter results in around 50% increase in sensitivity compared to a pore with half its diameter, which indicates the scope of design optimization in such systems.