Multiple MoS(2) Transistors for Sensing Molecule Interaction Kinetics

Atomically layered transition metal dichalcogenides (TMDCs) exhibit a significant potential to enable next-generation low-cost transistor biosensors that permit single-molecule-level quantification of biomolecules. To realize such potential biosensing capability, device-oriented research is needed for calibrating the sensor responses to enable the quantification of the affinities/kinetics of biomolecule interactions. In this work, we demonstrated MoS(2)-based transistor biosensors capable of detecting tumor necrosis factor – alpha (TNF-α) with a detection limit as low as 60 fM. Such a detection limit was achieved in both linear and subthreshold regimes of MoS(2) transistors. In both regimes, all sets of transistors exhibited consistent calibrated responses with respect to TNF-α concentration, and they resulted in a standard curve, from which the equilibrium constant of the antibody-(TNF-α) pair was extracted to be K(D) = 369 ± 48 fM. Based on this calibrated sensor model, the time-dependent binding kinetics was also measured and the association/dissociation rates of the antibody-(TNF-α) pair were extracted to be (5.03 ± 0.16) × 10(8) M(−1)s(−1) and (1.97 ± 0.08) × 10(−4) s(−1), respectively. This work advanced the critical device physics for leveraging the excellent electronic/structural properties of TMDCs in biosensing applications as well as the research capability in analyzing the biomolecule interactions with fM-level sensitivities.