Dielectric Coatings for Resistive Pulse Sensing Using Solid-State Pores.

The present study reports on the systematic characterization of the effectiveness of dielectric coating to tailor capture-to-translocation dynamics of single particles in solid-state pores. We covered the surface of SiN membranes with SiO, HfO, AlO, TiO, or ZnO, which allowed us to change the ζ-potential at the pore wall, reflecting the isoelectric points of these coating materials. Resistive pulse measurements of negatively charged polystyrene beads elucidated more facile electrophoretic capture of the particles and slower translocation motions in the channel under more negative electric potential at the oxide surface.

Quasi-Stable Salt Gradient and Resistive Switching in Solid-State Nanopores.

Understanding and control of ion transport in a fluidic channel is of crucial importance for iontronics. The present study reports on quasi-stable ionic current characteristics in a SiN nanopore under a salinity gradient. An intriguing interplay between electro-osmotic flow and local ion density distributions in a solid-state pore is found to induce highly asymmetric ion transport to negative differential resistance behavior under a 100-fold difference in the cross-membrane salt concentrations.

Tailoring Dielectric Surface Charge via Atomic Layer Thickness.

Channel surface property is a crucial factor that affects capture-to-translocation dynamics of single-particles in solid-state pores. Here, we show that atomically-thin dielectrics can be used to finely tune the pore wall surface potential. We isotopically coated alumina of atomically controlled thickness on a SiN micropore.