Mixed Termination of Ti₃C₂ MXene toward Better Sensing of Nucleobases: A Density Functional Theory Study

Applying MXenes, a recently discovered class of two-dimensional materials, for detection of nucleobases has been attracting much interest due to their excellence in electronic and optical properties. On the other hand, owing to the importance of nucleobase detection in DNA sequencing, testing of gene-related disease, and disease treatment, the study of MXenes in this field appears to be promising. This work focuses on the study of potential detection of nucleobases by mixed functionalization of titanium carbide MXene (Ti3C2) with oxygen and sulfur atoms, by employing first-principles calculations. Intrinsic mechanisms of nucleobase adsorption and the corresponding changes in the electronic properties of Ti3C2OS are studied through density of states, charge analysis, work function, and electrostatic potential calculations. Van der Waals-induced simulations reveal the adsorption energy of adenine (−0.77 eV), cytosine (−0.53 eV), guanine (−0.82 eV), thymine (−0.51 eV), and uracil (−0.62 eV) on Ti3C2OS. The calculated work function before and after the adsorption process shows the most changes for guanine, which leads to the highest sensitivity of this nucleobase among all other studied ones. Our results clearly show new pathways of detecting nucleobases that could pave the long track of human's journey for disease diagnoses and their treatment.