Center for NanoScience, Ludwigs-Maximilians-Universität Munich, Amalienstrasse 54, 80799 Munich, Germany.
Nat Chem. 2010 Sep;2(9):745-9. doi: 10.1038/nchem.722. Epub 2010 Jul 4.
The development of single-molecule techniques has afforded many new methods for the observation and assembly of supramolecular structures and biomolecular networks. We previously reported a method, known as the single-molecule cut-and-paste approach, to pick up and deposit individual DNA strands on a surface. This, however, required pre-functionalization of the surface with DNA strands complementary to those that were to be picked up and then deposited. Here we show that single molecules of double-stranded DNA, bound to the tip of an atomic force microscope, can be deposited on a bare gold electrode using an electrical trigger (surface potential cycling). The interactions between the DNA and the electrode were investigated and we found that double-stranded DNA chemisorbs to the gold electrode exclusively at its end through primary amine groups. We corroborated this finding in experiments in which only a single adenosine nucleotide on a polyethylene glycol spacer was 'electrosorbed' to the gold electrode.
单分子技术的发展为观察和组装超分子结构和生物分子网络提供了许多新方法。我们之前报道了一种方法，称为单分子切割和粘贴方法，用于在表面上拾取和放置单个 DNA 链。然而，这需要预先对表面进行功能化，使其与要拾取和放置的 DNA 链互补。在这里，我们表明，与原子力显微镜尖端结合的双链 DNA 分子可以使用电触发（表面电势循环）沉积在裸露的金电极上。研究了 DNA 与电极之间的相互作用，我们发现双链 DNA 通过伯胺基团仅在其末端专一地化学吸附到金电极上。在实验中，我们证实了这一发现，其中只有聚乙二醇间隔物上的单个腺苷核苷酸被“电吸附”到金电极上。
