Tayo Benjamin O, Walkup Michael A, Caliskan Serkan
School of Engineering, University of Central Oklahoma, Edmond, Oklahoma 73034, USA.
Department of Physical and Applied Sciences, University of Houston-Clear Lake, Houston, Texas 77058, USA.
AIP Adv. 2023 Aug 8;13(8):085213. doi: 10.1063/5.0160784. eCollection 2023 Aug.
We investigated the interaction of DNA nucleobases [adenine (A), guanine (G), thymine (T), and cytosine (C)] with single-layer TiC MXene using Van der Waals (vdW)-corrected density functional theory and non-equilibrium Green's function methods. All calculations were benchmarked against graphene. We showed that depending on the initial vertical height of a nucleobase above the TiC surface, two interaction mechanisms are possible, namely, physisorption and chemisorption. For graphene, DNA nucleobases always physisorbed onto the graphene surface irrespective of the initial vertical height of the nucleobase above the graphene sheet. The PBE+vdW binding energies for graphene are high (0.55-0.74 eV) and follow the order G > A > T > C, with adsorption heights in the range of 3.16-3.22 Å, indicating strong physisorption. For TiC, the PBE+vdW binding energies are relatively weaker (0.16-0.20 eV) and follow the order A > G = T > C, with adsorption heights in the range of 5.51-5.60 Å, indicating weak physisorption. The binding energies for chemisorption follow the order G > A > T > C, which is the same order for physisorption. The binding energy values (5.3-7.5 eV) indicate very strong chemisorption (∼40 times larger than the physisorption binding energies). Furthermore, our band structure and electronic transport analysis showed that for physisorption, there is neither significant variation in the band structure nor modulation in the transmission function and device density of states. The relatively weak physisorption and strong chemisorption show that TiC might not be capable of identifying DNA nucleobases using the physisorption method.
我们使用范德华（vdW）校正密度泛函理论和非平衡格林函数方法，研究了DNA核碱基（腺嘌呤（A）、鸟嘌呤（G）、胸腺嘧啶（T）和胞嘧啶（C））与单层TiC MXene的相互作用。所有计算均以石墨烯为基准。我们发现，根据核碱基在TiC表面上方的初始垂直高度，可能存在两种相互作用机制，即物理吸附和化学吸附。对于石墨烯，无论核碱基在石墨烯片上方的初始垂直高度如何，DNA核碱基总是物理吸附在石墨烯表面。石墨烯的PBE+vdW结合能较高（0.55 - 0.74 eV），且遵循G > A > T > C的顺序，吸附高度在3.16 - 3.22 Å范围内，表明存在强物理吸附。对于TiC，PBE+vdW结合能相对较弱（0.16 - 0.20 eV），遵循A > G = T > C的顺序，吸附高度在5.51 - 5.60 Å范围内，表明存在弱物理吸附。化学吸附的结合能遵循G > A > T > C的顺序，与物理吸附顺序相同。结合能值（5.3 - 7.5 eV）表明存在非常强的化学吸附（约为物理吸附结合能的40倍）。此外，我们的能带结构和电子输运分析表明，对于物理吸附，能带结构没有显著变化，传输函数和器件态密度也没有调制。相对较弱的物理吸附和较强的化学吸附表明，TiC可能无法使用物理吸附方法识别DNA核碱基。
