Center for Technology Innovation - Healthcare, Research & Development Group, Hitachi Ltd, 1-280 Higashi-Koigakubo, Kokubunji, Tokyo 185-8601, Japan.
Nanoscale. 2018 Nov 15;10(44):20844-20850. doi: 10.1039/c8nr04238a.
DNA sequencing via solid-state nanopores is a promising technique with the potential to surpass the performance of conventional sequencers. However, the identification of all four nucleotide homopolymers with a typical SiN nanopore is 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 into a single-stranded structure by disrupting the hydrogen-bonding network between the guanines and preventing the binding of the K+ ion to G-quartets. 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 contribute to the development of practical DNA sequencing with a solid-state nanopore.
通过固态纳米孔进行 DNA 测序是一种很有前途的技术，有可能超越传统测序仪的性能。然而，用典型的 SiN 纳米孔来识别所有四种核苷酸的同源聚合物尚未得到明确证明，因为在典型的 KCl 水溶液中，鸟嘌呤同源聚合物会迅速形成 G-四链体。为了解决这个问题，我们引入了碱性 CsCl 水溶液，通过破坏鸟嘌呤之间的氢键网络并阻止 K+离子与 G-四联体结合，将 G-四链体变性为单链结构。使用这种碱性 CsCl 溶液，我们提供了一个原理证明，即根据它们的阻塞电流，所有四种核苷酸的单链 DNA 同聚物都可以用相同的单个纳米孔进行统计识别。我们还证实，三核苷酸的三嵌段 DNA 共聚物表现出三峰高斯分布，其峰对应于 DNA 同聚物的峰。我们的研究结果为使用固态纳米孔进行实际的 DNA 测序奠定了基础。
