Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189, China.
J Phys Chem Lett. 2021 Jul 22;12(28):6469-6477. doi: 10.1021/acs.jpclett.1c01163. Epub 2021 Jul 9.
Many biological assays require effectively and sensitively sorting DNA fragments. Here, we demonstrate a solid-state nanopore platform for label-free detection and separation of short single-stranded DNA (ssDNA) fragments (<100 nt), based on their length-dependent translocation behaviors. Our experimental data show that each sized pore has a passable length threshold. The negative charged ssDNA fragments with length smaller than the threshold can be electrically facilitated driven through the correspondingly sized nanopore along the direction of electric field. In addition, the passable length threshold increases with the pore size enlarging. As a result, this phenomenon is able to be applicable for the controllable selectivity of ssDNA by tuning nanopore size, and the selectivity limitation is up to 30nt. Numerical simulation results indicate the translocation direction of ssDNA is governed by the competition of electroosmosis and electrophoresis effects on the ssDNA and offer the relationship between passable length threshold and pore size.
许多生物检测都需要有效地和敏感地对 DNA 片段进行分类。在这里，我们展示了一种基于其长度依赖性的转运行为的固态纳米孔平台，用于无标记检测和分离短的单链 DNA（ssDNA）片段（<100nt）。我们的实验数据表明，每个尺寸的孔都有一个可通过的长度阈值。长度小于该阈值的带负电荷的 ssDNA 片段可以在电场的作用下，通过相应尺寸的纳米孔沿着电场的方向被电辅助驱动。此外，可通过的长度阈值随着孔径的增大而增大。因此，这种现象可通过调节纳米孔尺寸来实现 ssDNA 的可控选择性，选择性的限制可达 30nt。数值模拟结果表明，ssDNA 的转运方向由 ssDNA 上的电渗流和电泳效应的竞争决定，并提供了可通过长度阈值和孔径之间的关系。
