Multiple MoS2 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 MoS2-based transistor biosensors capable of detecting tumor necrosis factor - alpha (TNF-alpha) with a detection limit as low as 60 fM. Such a detection limit was achieved in both linear and subthreshold regimes of MoS2 transistors. In both regimes, all sets of transistors exhibited consistent calibrated responses with respect to TNF-alpha concentration, and they resulted in a standard curve, from which the equilibrium constant of the antibody-(TNF-alpha) 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-alpha) pair were extracted to be (5.03 +/- 0.16) x 10(8)M(-1)s(-1) and (1.97 +/- 0.08) x 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.