School of Mechanical Engineering, Southeast University, Nanjing, P. R. China.
Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing, P. R. China.
Electrophoresis. 2019 Aug;40(16-17):2117-2124. doi: 10.1002/elps.201800537. Epub 2019 Feb 27.
Nanopore sensor has been developed as a promising technology for DNA sequencing at the single-base resolution. However, the discrimination of homopolymers composed of guanines from other nucleotides has not been clearly revealed due to the easily formed G-quadruplex in aqueous buffers. In this work, we report that a tiny silicon nitride nanopore was used to sieve out G tetramers to make sure only homopolymers composed of guanines could translocate through the nanopore, then the 20-nucleotide long ssDNA homopolymers could be identified and differentiated. It is found that the size of the nucleotide plays a major role in affecting the current blockade as well as the dwell time while DNA is translocating through the nanopore. By the comparison of translocation behavior of ssDNA homopolymers composed of nucleotides with different volumes, it is found that smaller nucleotides can lead to higher translocation speed and lower current blockage, which is also found and validated for the 105-nucleotide long homopolymers. The studies performed in this work will improve our understanding of nanopore-based DNA sequencing at single-base level.
纳米孔传感器已被开发为一种有前途的单碱基分辨率 DNA 测序技术。然而，由于在水缓冲液中容易形成 G-四链体，因此尚未清楚地揭示由鸟嘌呤组成的寡聚核苷酸的区分。在这项工作中，我们报告了使用微小的氮化硅纳米孔来筛选 G 四聚体，以确保只有由鸟嘌呤组成的均聚物可以通过纳米孔移位，然后可以识别和区分 20 个核苷酸长的 ssDNA 均聚物。研究发现，核苷酸的大小在影响电流阻断以及 DNA 通过纳米孔迁移时的停留时间方面起着主要作用。通过比较具有不同体积的核苷酸组成的 ssDNA 均聚物的迁移行为，发现较小的核苷酸可以导致更高的迁移速度和更低的电流阻断，对于 105 个核苷酸长的均聚物也发现并验证了这一点。这项工作中的研究将提高我们对单碱基水平基于纳米孔的 DNA 测序的理解。
