Tanaka Hiroyuki, Kawai Tomoji
The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki, Osaka, Japan.
Nat Nanotechnol. 2009 Aug;4(8):518-22. doi: 10.1038/nnano.2009.155. Epub 2009 Jul 5.
The scanning tunnelling microscope is capable of the real-space imaging and spectroscopy of molecules on an atomic scale. Numerous attempts have been made to use the scanning tunnelling microscope to sequence single DNA molecules, but difficulties in preparing samples of long-chain DNA molecules on surfaces, and problems in reproducing results have limited these experiments. Here, we report single-molecule DNA sequencing with a scanning tunnelling microscope by using an oblique pulse-injection method to deposit the molecules onto a copper surface. First, we show that guanine bases have a distinct electronic state that allows them to be distinguished from the other nucleic acid bases. Then, by comparing data on M13mp18, a single-stranded phage DNA, with a known base sequence, the 'electronic fingerprint' of guanine bases in the DNA molecule is identified. These results show that it is possible to sequence individual guanine bases in real long-chain DNA molecules with high-resolution scanning tunnelling microscope imaging and spectroscopy.
扫描隧道显微镜能够在原子尺度上对分子进行实空间成像和光谱分析。人们已经进行了大量尝试，试图利用扫描隧道显微镜对单个DNA分子进行测序，但在表面制备长链DNA分子样品时遇到的困难以及结果重现性问题限制了这些实验。在此，我们报告了利用扫描隧道显微镜进行单分子DNA测序的方法，即采用斜脉冲注入法将分子沉积到铜表面。首先，我们表明鸟嘌呤碱基具有独特的电子态，这使得它们能够与其他核酸碱基区分开来。然后，通过将单链噬菌体DNA M13mp18的数据与已知碱基序列进行比较，确定了DNA分子中鸟嘌呤碱基的“电子指纹”。这些结果表明，利用高分辨率扫描隧道显微镜成像和光谱分析，有可能对真实长链DNA分子中的单个鸟嘌呤碱基进行测序。
