Unraveling Single-Stranded DNA in a Solid-State Nanopore

作者：Kowalczyk Stefan W; Tuijtel Maarten W; Donkers Serge P; Dekker Cees^*

来源：Nano Letters, 2010, 10(4): 1414-1420.

DOI：10.1021/nl100271c

• Nanopores
• translocation
• single-stranded DNA
• sequencing

Solid-state nanopores are an emerging class of single-molecule sensors. Whereas most studies so far focused on double-stranded DNA (dsDNA) molecules, exploration of single-stranded DNA (ssDNA) is of great interest as well, for example to employ such a nanopore device to read out the sequence. Here, we study the translocation of long random-sequence ssDNA through nanopores. Using atomic force microscopy, we observe the ssDNA to hybridize into a random coil, forming blobs of around 100 am in diameter For 7 kb ssDNA. These large entangled structures have to unravel, when they arrive at the pore entrance. Indeed, we observe strong blockade events with a translocation time that is exponentially dependent on voltage, tau similar to e-(VIV0). Interestingly, this is very different than for dsDNA, for which tau similar to 1/V. We report translocations of ssDNA but also of ssDNA dsDNA constructs where we compare the conductance-blockade levels for ssDNA versus dsDNA as a function of voltage.

• 出版日期2010-4