Capture and Translocation of Nucleic Acids into Sub-5 nm Solid-State Nanopores

Abstract

Nanopores have emerged as single-molecule analytic tools for fundamental biophysical characterization of nucleic acids as well as for future genomic applications. The enormous interest in single-molecule analysis has spurred the development of many different approaches to nanopore fabrication. Of these, ultrathin solid-state membranes are the most promising substrates, combining exceptional robustness and control over pore size and shape with an inherently planar geometry that enables parallel detection with nanopore arrays. Moreover, nanopores with diameters in the range of 1–5 nm represent an important size regime for studying nucleic acids, as these pores can translocate long DNA and RNA molecules in a linear fashion, enabling readout of local nucleic acid structure with unparalleled read-length. In this review, we focus on two fundamental aspects of nucleic acid analysis using nanopores, namely the process of DNA capture and the subsequent translocation dynamics. We compile here a multi-parametric study of double-stranded DNA molecules of lengths ranging from 50 to 50,000 bp, and discuss the influence of DNA length, applied voltage, temperature, and salt buffer concentrations on the capture and translocation processes.