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

Electrolytic Gated Organic Field-Effect Transistors for Application in Biosensors—A Review

“…However, graphene has been shown to have low sensitivity due to lack of bandgap. For this reason, other electrolyte-gated inorganic FETs are also promising, for example based on MoS 2 semiconductor [48]. In EGOFETs, the gate material also influences the figures of merit of the devices, particularly the threshold potential V T [49,50].…”

Biocompatible, large-format, inkjet printed heterostructure MoS2-graphene photodetectors on conformable substrates

“…14,15 While the photonic and optoelectronic properties of 2D materials are being intensively investigated, 16,17 their implementation to biosensing and biomedical applications is limited thus far, although some reports have emerged recently. 18,19 Given that these materials exhibit a weak interlayer bonding through the van der Waals interaction, solvents and mild agitation through sonication allows layer separation into monolayer or few-layer nanomembranes from the bulk crystal. 20 To advance the utility of these materials for biosensing and biomedical applications, the biocompatibility of 2D graphene and MoS 2 with both mouse embryonic fibroblasts (STO) and human esophageal fibroblasts (HEF) cell lines was explored, for photodetector applications with potential for retinal prostheses.…”

Phosphorous doped p-type MoS2 polycrystalline thin films via direct sulfurization of Mo film

“…1 Thus, several applications have already been reported in research, such as field-effect transistors (FETs), 2 photodetectors, 3 inverters, 4 and random access memory circuits, 5 including bio-sensors 6 and solar cells 7 due to its attractive properties such as high carrier mobility of ∼100-200 cm 2 /Vs at room temperature, 8 large current on/off ratio (∼10 8 ) in FETs, 9 strong photoluminescence (PL), 10 and tunable valley spin polarization, 11 etc. For realizing these applications, both n-and p-type materials are needed to form junctions and support bipolar carrier conduction.…”