ACS Appl Bio Mater. 2021 Feb 15;4(2):1403-1412. doi: 10.1021/acsabm.0c01309. Epub 2020 Dec 31.
Extended line defects in graphene (ELDG) sheets have been found to be promising for biomolecule sensing applications. By means of the consistent-exchange van der Waals density-functional (vdW-DF-cx) method, the electronic, structural, and quantum transport properties of the ELDG nanogap setup has been studied when a DNA nucleotide molecule is positioned inside the nanogap electrodes. The interaction energy () values indicate charge transfer interaction between the nucleotide molecule and electrode edges. The charge density difference plots reveal that charge fluctuates around the ELDG nanogap edges adjacent to the nucleotides. This charge redistribution grounds the modulation of electronic charge transport in the ELDG nanogap device. Further, we study the electronic transverse-conductance and tunnelling current-voltage (-) characteristics across two closely spaced ELDG nanogap electrodes using the density functional theory and the nonequilibrium Green's function methods when a DNA nucleotide is translocated through the nanogap. Our outcomes indicate that the ELDG nano gap device could allow sequencing of DNA nucleotides with a robust and consistent yield, giving the tunneling electric current signals that vary by more than 1 order of magnitude electric current () for the different DNA nucleotides. So, we predict that the ELDG nanogap-based tunneling device can be suitable for sequencing DNA nucleobases.
石墨烯中的扩展线缺陷 (ELDG) 已被证明在生物分子传感应用中具有广阔的前景。通过一致交换范德华密度泛函 (vdW-DF-cx) 方法，研究了当 DNA 核苷酸分子位于纳米电极的纳米间隙内时，ELDG 纳米间隙装置的电子、结构和量子输运特性。相互作用能 () 值表明核苷酸分子与电极边缘之间存在电荷转移相互作用。电荷密度差图显示，电荷在与核苷酸相邻的 ELDG 纳米间隙边缘周围波动。这种电荷再分布是电子电荷在 ELDG 纳米间隙器件中输运调制的基础。此外，当 DNA 核苷酸通过纳米间隙传输时，我们使用密度泛函理论和非平衡格林函数方法研究了两个紧密间隔的 ELDG 纳米间隙电极的电子横向电导和隧穿电流-电压 (-) 特性。我们的研究结果表明，ELDG 纳米间隙器件可以允许对 DNA 核苷酸进行测序，具有稳健和一致的产量，不同 DNA 核苷酸的隧穿电流信号变化超过 1 个数量级 ()。因此，我们预测基于 ELDG 纳米间隙的隧穿器件可适用于 DNA 碱基测序。
