Magnetic Sensing of Ion Transport in a Single Nanopore

Developing magnetic measurement techniques for nanofluidic systems will unlock the access to the unexplored information on nanoconfined transport, which remains elusive. Herein, we integrate an atomic magnetometer with an artificial nanopore, constructing a magnetic sensing-based nanofluidic measurement system to profile nanoscale ion dynamics. Through magnetic noise suppression by a multilayer shielding system and configuration optimization with an optically pumped magnetometer, our system exhibits exceptional detection performances with a sensitivity reaching 12.38 fT/Hz^1/2 and current responsivity ascending to 3.87 nA in the scenario of single nanopore transport. By tracking ultraweak magnetic signals, this system precisely presents the magnetic correlation with ionic current flow and reveals the dynamic perturbation of ion motion induced by nanoparticles. Theoretical simulations further demonstrate the superiority of magnetic measurement for characterizing ion transport in the spatiotemporal dimension, validating the potential of magnetism-based techniques for understanding magnetodynamics in single biological channels and unveiling new prospects for nanofluidics.