Electrical properties of DNA critically depend on the way DNA molecules are integrated within the electronics, particularly on DNA–electrode immobilization strategies. Here, we show that the rate of electron transport in DNA duplexes spacer-free tethered to gold via the adenosine terminal region (a dA₁₀ tag) is enhanced compared to the hitherto reported DNA–metal electrode tethering chemistries. The rate of DNA-mediated electron transfer (ET) between the electrode and methylene blue intercalated into the dA₁₀-tagged DNA duplex approached 361 s^–1 at a ca. half-monolayer DNA surface coverage Γ_DNA (with a linear regression limit of 670 s^–1 at Γ_DNA → 0), being 2.7-fold enhanced compared to phosphorothioated dA₅* tethering (6-fold for the C₆-alkanethiol linker representing an additional ET barrier). X-ray photoelectron spectroscopy evidenced dA₁₀ binding to the Au surface via the purine N, whereas dA₅* predominantly coordinated to the surface via sulfur atoms of phosphothioates. The latter apparently induces the DNA strand twist in the point of surface attachment affecting the local DNA conformation and, as a result, decreasing the ET rates through the duplex. Thus, a spacer-free DNA coupling to electrodes via dA₁₀ tags thus allows a perspective design of DNA electronic circuits and sensors with advanced electronic properties and no implication from more expensive, synthetic linkers.

中文翻译：

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通过dA ₁₀标签将无间隔DNA双链体束缚在金上的电子转移

DNA的电特性主要取决于DNA分子在电子设备中的整合方式，尤其取决于DNA电极固定策略。在这里，我们显示，与迄今报道的DNA-金属电极束缚化学方法相比，DNA双链体无间隔物通过腺苷末端区域（dA ₁₀标签）与金的电子传输速率得到了提高。电极与插入dA ₁₀标签的DNA双链体中的亚甲基蓝之间的DNA介导的电子转移（ET）速率在大约361 s ^–1左右。半单层DNA表面覆盖Γ _DNA（具有670秒的线性回归极限^-1在Γ _DNA→0），与硫代磷酸化dA ₅ *系链相比提高了2.7倍（对于C ₆链烷硫醇连接子来说，它是附加的ET屏障的6倍）。X射线光电子能谱证明dA ₁₀通过嘌呤N与Au表面结合，而dA ₅ *主要通过硫代磷酸酯的硫原子与Au表面结合。后者显然会在表面附着点诱导DNA链扭曲，从而影响局部DNA构象，并因此降低通过双链体的ET率。因此，无间隔的DNA通过dA ₁₀耦合到电极 因此，标签允许对具有先进电子特性的DNA电子电路和传感器进行透视设计，而不必考虑更昂贵的合成接头的影响。