Unraveling Single-Stranded DNA in a Solid-State Nanopore

• DOI: 10.1021/nl100271c
• Publication Date: 2010-03-17T12:32:32Z
• Authors: Stefan W. Kowalczyk; Maarten W. Tuijtel; Serge P. Donkers; Cees Dekker
• Keywords: Nanopore

Solid-state nanopores are an emerging class of single-molecule sensors. Whereas most studies so far focused on double-stranded DNA (dsDNA) molecules, exploration single-stranded (ssDNA) is great interest as well, for example to employ such a nanopore device read out the sequence. Here, we study translocation long random-sequence ssDNA through nanopores. Using atomic force microscopy, observe hybridize into random coil, forming blobs around 100 nm in diameter 7 kb ssDNA. These large entangled structures have unravel, when they arrive at pore entrance. Indeed, strong blockade events with time that exponentially dependent voltage, τ ∼ e−V/V0. Interestingly, this very different than dsDNA, which 1/V. We report translocations but also ssDNA−dsDNA constructs where compare conductance-blockade levels versus dsDNA function voltage.