Identification of Lung Cancer Biomarkers by Nanosensors Based on Titanium Carbide (Ti₃C₂T_x) 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 (Ti 3 C 2 T 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 (C 9 H 20 ), aniline (C 6 H 7 N), ethylbenzene (C 8 H 10 ), isoprene (C 5 H 8 ), and o -toluidine (C 7 H 9 N), are selected and their adsorption mechanism with Ti 3 C 2 T 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 C 9 H 20 (−0.766 to −0.878) C 6 H 7 N (−0.663 to −1.02), C 8 H 10 (−0.653 to −0.877), C 5 H 8 (−0.505 to −3.49), and C 7 H 9 N (−0.691 to −1.15 eV) on Ti 3 C 2 F 2, Ti 3 C 2 O 2, Ti 3 C 2 (OH) 2, and Ti 3 C 2 S 2, respectively. Intrinsic mechanisms of VOCs adsorption and the corresponding changes in the electronic properties of Ti 3 C 2 T x are studied through charge analysis, density of states, electrostatic potentials, and work function calculations. Further, the sensing behavior of the VOCs with Ti 3 C 2 T x has been explored through statistical thermodynamic analysis for practical applications. Our results clearly show that Ti 3 C 2 T x MXenes hold great potential as efficient nanosensors for the detection of VOCs related to lung cancer diagnosis at an early stage.