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[18a-222-1] Identification of four-nucleotide single-stranded DNA homopolymers with a solid-state nanopore in alkaline CsCl solution
Keywords:nanopore, DNA sequencer
DNA sequencing via solid-state nanopore is a promising technology with the potential to surpass the performance of conventional sequencers. However, the identification of all four nucleotides with a typical SiN nanopore has yet to be clearly demonstrated because a guanine homopolymer rapidly forms a G-quadruplex in a typical KCl aqueous solution. To address this issue, we introduced an alkaline CsCl aqueous solution, which denatures the G-quadruplex to a single-stranded structure by disrupting the hydrogen-bonding network between the guanines. Using this alkaline CsCl solution, we provided a proof of principle that single-stranded DNA homopolymers of all four nucleotides could be statistically identified according to their blockade currents with the same single nanopore. We also confirmed that a triblock DNA copolymer of three nucleotides exhibited a trimodal Gaussian distribution whose peaks correspond to those of the DNA homopolymers. Our findings will open the door to achieving solid-state nanopore sequencing.