Extreme Slowdown of dsDNA and RNA:DNA Hybrids in Solid-state Nanopores for LiCl concentrations above 4 mol/L

Solid-state nanopores enable single-molecule detection and characterization through ionic-current measurements, but rapid translocation can limit the resolution of molecular features. Here, we investigated the translocation of 7.2 kb dsDNA and 3.3 kb RNA:DNA hybrids at LiCl concentrations extending to 7 mol/L. Both constructs exhibited a substantial increase of ≳ 500% in mean translocation time when increasing LiCl concentration from 2--3 M to 7 M . We also observed a decrease in translocation frequency at increasing LiCl concentration. Both observations indicate a reduction in the effective electric driving force. Further analysis indicates a substantial decrease in the relative width of secondary peaks induced by labels on the molecule. Our results show that increasing salt concentration beyond 4 mol/L is an accessible way for increasing translocation time in solid-state nanopore sensing, with possible implications for barcode sensing resolution.