Nanopore Sensors for Enhanced Detection of Nanoparticles

Nanopore sensing is a technique based on the Coulter principle to analyze and characterize biological molecules with single molecule resolution. However, its use in nanoparticle characterization has been constrained by the need to tailor the nanopore size to match the size of the analyte, precluding the analysis of heterogenous samples. Additionally, nanopore sensors often require the use of high salt concentrations to improve the signal-to-noise ratio, which further limits their ability to study a wide range of nanoparticles that are unstable at high ionic strength. Here we show the development of nanopore sensors enhanced by a polymer electrolyte system, enabling the analysis of heterogenous nanoparticle mixtures at low ionic strength. We present a finite element model to explain the anomalous conductive pulse signals observed and compare these results with experiments. Furthermore, we demonstrate the wide applicability of the method, by characterizing metallic nanospheres with different sizes, plasmonic nanostars with various degrees of branching, and protein-based spherical nucleic acids with discrete oligonucleotide loadings. We anticipate that our system will complement existing nanomaterials characterization techniques and enable the electrical and real-time optimization workflow for engineering a wide range of nanomaterials. ### Competing Interest Statement The authors have declared no competing interest.