Identification of Lung Cancer Biomarkers by Nanosensors Based on Titanium Carbide (Ti3C2Tx) MXenes

Inspired by the importance of early diagnosis of lung cancer, which is responsible for the most cancer-related deaths worldwide, we propose a nanosensor based on titanium carbide MXenes (Ti₃C₂T_x; T_x = O, S, F, and OH) capable of detecting selected volatile organic compounds (VOCs) from human breath. A set of representative VOCs, such as 2,3,4-trimethylhexane (C₉H₂₀), aniline (C₆H₇N), ethylbenzene (C₈H₁₀), isoprene (C₅H₈), and o-toluidine (C₇H₉N), are selected and their adsorption mechanism with Ti₃C₂T_x has been studied comprehensively by means of first-principles density functional theory calculations. Van der Waals-induced simulations reveal the range of adsorption energies of C₉H₂₀ (−0.766 to −0.878) C₆H₇N (−0.663 to −1.02), C₈H₁₀ (−0.653 to −0.877), C₅H₈ (−0.505 to −3.49), and C₇H₉N (−0.691 to −1.15 eV) on Ti₃C₂F₂, Ti₃C₂O₂, Ti₃C₂(OH)₂, and Ti₃C₂S₂, respectively. Intrinsic mechanisms of VOCs adsorption and the corresponding changes in the electronic properties of Ti₃C₂T_x are studied through charge analysis, density of states, electrostatic potentials, and work function calculations. Further, the sensing behavior of the VOCs with Ti₃C₂T_x has been explored through statistical thermodynamic analysis for practical applications. Our results clearly show that Ti₃C₂T_x MXenes hold great potential as efficient nanosensors for the detection of VOCs related to lung cancer diagnosis at an early stage.