MoS₂ Field-Effect Transistor for Next-Generation Label-Free Biosensors

TLDR

Field‑effect transistor biosensors are attractive for rapid, inexpensive, label‑free detection, yet bulk 3D designs suffer low sensitivity and 1D nanostructures, though more sensitive, face fabrication challenges that limit practical use. The study introduces MoS₂‑based FET biosensors that combine high sensitivity with easy patternability and fabrication. The authors develop MoS₂‑based FETs using its 2D layered structure and theoretically demonstrate that MoS₂ enables scalable biosensor devices while preserving sensitivity, facilitating single‑molecule detection. The MoS₂ FETs achieve a pH sensitivity of 713 over pH 3–9, detect proteins at 100 fM with sensitivity 196, outperform graphene‑based FETs by more than 74‑fold, and, owing to their flexibility and transparency, promise low‑cost, next‑generation biosensors.

Abstract

Biosensors based on field-effect transistors (FETs) have attracted much attention, as they offer rapid, inexpensive, and label-free detection. While the low sensitivity of FET biosensors based on bulk 3D structures has been overcome by using 1D structures (nanotubes/nanowires), the latter face severe fabrication challenges, impairing their practical applications. In this paper, we introduce and demonstrate FET biosensors based on molybdenum disulfide (MoS2), which provides extremely high sensitivity and at the same time offers easy patternability and device fabrication, due to its 2D atomically layered structure. A MoS2-based pH sensor achieving sensitivity as high as 713 for a pH change by 1 unit along with efficient operation over a wide pH range (3–9) is demonstrated. Ultrasensitive and specific protein sensing is also achieved with a sensitivity of 196 even at 100 femtomolar concentration. While graphene is also a 2D material, we show here that it cannot compete with a MoS2-based FET biosensor, which surpasses the sensitivity of that based on graphene by more than 74-fold. Moreover, we establish through theoretical analysis that MoS2 is greatly advantageous for biosensor device scaling without compromising its sensitivity, which is beneficial for single molecular detection. Furthermore, MoS2, with its highly flexible and transparent nature, can offer new opportunities in advanced diagnostics and medical prostheses. This unique fusion of desirable properties makes MoS2 a highly potential candidate for next-generation low-cost biosensors.