The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
Nat Chem. 2009 May;1(2):156-9. doi: 10.1038/nchem.171. Epub 2009 Apr 12.
Interest in using DNA as a building block for nanoelectronic sensors and devices stems from its efficient hole-conducting properties and the relative ease with which it can be organized into predictable nanometre-sized two- and three-dimensional structures. However, because a hole migrates along DNA through the highest occupied molecular orbital of the guanine bases, its conductivity decreases as the adenine-thymine base-pair content increases. This means that there are limitations on what sequences can be used to construct functional nanoelectronic circuits, particularly those rich in adenine-thymine pairs. Here we show that the charge-transfer efficiency can be dramatically increased in a manner independent of guanine-cytosine content by adjusting the highest occupied molecular orbital level of the adenine-thymine base pair to be closer to that of the guanine-cytosine pair. This is achieved by substituting the N7 nitrogen atom of adenine with a C-H group to give 7-deazaadenine, which does not disturb the complementary base pairing observed in DNA.
人们对将 DNA 用作纳米电子传感器和器件的构建模块很感兴趣，这是因为它具有高效的空穴传导特性，并且相对容易将其组织成可预测的纳米级二维和三维结构。然而，由于空穴通过 DNA 沿着鸟嘌呤碱基的最高占据分子轨道迁移，因此随着腺嘌呤-胸腺嘧啶碱基对含量的增加，其电导率会降低。这意味着可以用来构建功能纳米电子电路的序列受到限制，特别是那些富含腺嘌呤-胸腺嘧啶对的序列。在这里，我们表明通过调整腺嘌呤-胸腺嘧啶碱基对的最高占据分子轨道能级，使其更接近鸟嘌呤-胞嘧啶碱基对，可以在不依赖鸟嘌呤-胞嘧啶含量的情况下显著提高电荷转移效率。这是通过用 C-H 基团取代腺嘌呤的 N7 氮原子来实现的，这不会干扰在 DNA 中观察到的互补碱基配对。
