Beckman Institute, University of Illinois, Urbana, IL 61801, USA.
Nanotechnology. 2010 Oct 1;21(39):395501. doi: 10.1088/0957-4484/21/39/395501. Epub 2010 Sep 1.
It is now possible to slow and trap a single molecule of double-stranded DNA (dsDNA), by stretching it using a nanopore, smaller in diameter than the double helix, in a solid-state membrane. By applying an electric force larger than the threshold for stretching, dsDNA can be impelled through the pore. Once a current blockade associated with a translocating molecule is detected, the electric field in the pore is switched in an interval less than the translocation time to a value below the threshold for stretching. According to molecular dynamics (MD) simulations, this leaves the dsDNA stretched in the pore constriction with the base-pairs tilted, while the B-form canonical structure is preserved outside the pore. In this configuration, the translocation velocity is substantially reduced from 1 bp/10 ns to approximately 1 bp/2 ms in the extreme, potentially facilitating high fidelity reads for sequencing, precise sorting, and high resolution (force) spectroscopy.
现在，可以通过使用直径小于双螺旋的纳米孔拉伸双链 DNA（dsDNA）来减慢和捕获单个 dsDNA 分子。通过施加大于拉伸阈值的电场力，可以将 dsDNA 推动穿过孔。一旦检测到与迁移分子相关的电流阻断，就会在小于迁移时间的间隔内将孔中的电场切换到低于拉伸阈值的值。根据分子动力学（MD）模拟，这会使 dsDNA 在孔收缩处拉伸，碱基对倾斜，而 B 型标准结构在孔外保持不变。在这种构型下，迁移速度从 1 bp/10 ns 到极端情况下的大约 1 bp/2 ms 显著降低，这可能有利于测序、精确分拣和高分辨率（力）光谱学的高保真读取。
