University of Notre Dame , Stinson-Remick Hall, Notre Dame Avenue, Notre Dame, Indiana 46556, United States.
ACS Nano. 2014 Jun 24;8(6):5484-93. doi: 10.1021/nn405331t. Epub 2014 May 28.
We report direct, concurrent measurements of the forces and currents associated with the translocation of a single-stranded DNA molecule tethered to the tip of an atomic force microscope (AFM) cantilever through synthetic pores with topagraphies comparable to the DNA. These measurements were performed to gauge the signal available for sequencing and the electric force required to impel a single molecule through synthetic nanopores ranging from 1.0 to 3.5 nm in diameter in silicon nitride membranes 6-10 nm thick. The measurements revealed that a molecule can slide relatively frictionlessly through a pore, but regular fluctuations are observed intermittently in the force (and the current) every 0.35-0.72 nm, which are attributed to individual nucleotides translating through the nanopore in a turnstile-like motion.
我们报告了通过与 DNA 拓扑结构相当的合成孔，对与原子力显微镜（AFM）悬臂尖端相连的单链 DNA 分子的迁移相关的力和电流进行的直接、同时测量。这些测量是为了衡量用于测序的信号以及推动单分子通过合成纳米孔所需的电力，这些纳米孔的直径从 1.0 到 3.5nm，位于 6-10nm 厚的氮化硅膜中。测量结果表明，分子可以相对无摩擦地在孔中滑动，但每隔 0.35-0.72nm 就会间歇性地观察到力（和电流）的规则波动，这归因于单个核苷酸以旋转门样的运动通过纳米孔平移。
