Metrology of Nanoscale Objects Using Nanopores

Solid-state nanopore serves as a versatile tool for single-particle analysis of nanoscale objects, enabling the measurement of their geometrical and physicochemical properties with molecular precision. When a bias drives an analyte to translocate through a nanopore, ionic current blockades encode information on the object's size, shape, charge, and dynamics. Compared with biological nanopores, solid-state nanopores offer superior mechanical stability, broader operational ranges, and easier integration with optical or mechanical characterization systems. This chapter introduces the concept of nanopore tomography (NT), which focuses on extracting quantitative geometrical parameters rather than genomic sequence information. We discuss the experimental considerations in nanopore characterization, including noise sources, sampling rate limitations, and filtering effects that distort short translocation events. The event charge deficit (ECD) emerges as a robust parameter preserved under signal filtering, allowing reliable particle fingerprinting. Furthermore, multiphysics coupled finite element modeling is presented to simulate electrokinetic processes and translocation dynamics, revealing the nonlinear dependence of current blockade on voltage and the contributions of electrophoretic and electroosmotic forces. Together, these insights advance nanopore-based metrology toward high-throughput, label-free, and nondestructive characterization of biomolecules, viruses, and nanoparticles.