DNA volume, topology, and flexibility dictate nanopore current signals Yunxuan Li , Sarah E. Sandler, Ulrich F. Keyser, Jinbo Zhu Cavendish Laboratory, University of Cambridge, UK
Nanopores have developed into powerful single-molecule sensors capable of identifying and characterizing small polymers, such as DNA, by electrophoretically driving them through a nanoscale pore and monitoring temporary blockades in ionic pore current. However, the relationship between nanopore signals and the topology and flexibility of DNA remains only partly understood. Herein, we use a programmable DNA carrier platform with two reference sites and four functional sites to capture carefully designed DNA nanostructures. Controlled translocation experiments through our glass nanopores allow us to disentangle the influence of DNA physical properties on the current blockade signal. We vary DNA topology by changing the length, strand duplications, sequence, unpaired nucleotides, and rigidity of the analyte DNA and find that the ionic current drop is mainly determined by the volume and flexibility of the DNA nanostructure in the nanopore. Finally, we use our understanding of the role of DNA topology to discriminate circular single-stranded DNA molecules from linear ones with the same number of nucleotides using the nanopore signal.
P14
© The Author(s), 2023
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