Quantifying the growth mechanism of solid-state nanopores under high-voltage conditioning

Abstract

Solid-state nanopores exhibit dynamically variable sizes influenced by buffer conditions and applied electric field. While dynamical pore behavior can complicate biomolecular sensing, it also offers opportunities for controlled, in situ modification of pore size post-fabrication. In order to optimally harness solid-state pore dynamics for controlled growth, there is a need to systematically quantify pore growth dynamics and ideally develop quantitative models to describe pore growth. Using high-voltage pulse conditioning, we investigate the expansion of nanopores and track their growth over time. Our findings reveal that pore growth follows a two-regime model: an initial transient regime characterized by an exponential rise, followed by a steady-state regime with linear growth. The pore growth rate increases with voltage, while the duration of the transition regime decreases with voltage. We propose a simple electrochemical etching model based on hydrolysis and solute removal to quantify time-dynamics of growing pores and rationalize the mechanism of electric-field driven pore growth, with numerical solutions aligning closely with experimental data. These insights enhance the understanding of nanopore conditioning, providing a theoretical framework for controlled pore size modification.