Optimizing the Sensitivity of DNA Concentration Measurements using Nanopores

The capture rate of linear dsDNA through solid-state nanopores is subject to significant variations, the nature of which remains unknown. To better understand the underlying physical processes responsible for these variations, we present nanopore capture rate data of dsDNA fragments of varying sizes for a wide range of experimental conditions. We use CBD-fabricated (controlled breakdown) nanopores to study the capture kinetics of DNA in pores of different sizes, solutions of different salt concentrations and pH. This is achieved by studying the dependencies of nanopore-capture on the applied voltage and DNA length, through which the two known capture regimes emerge. Furthermore, we investigate the translocation and capture properties under a salt asymmetry across the membrane and show that the conditions for the two capture regimes to emerge change compared to the symmetric case. These results are helping to develop a better fundamental understanding of the nanopore capture process, and may find applications in quantification of biological molecule concentrations using solid-state nanopores.