Tungsten Disulfide Nanosheet-Based Field-Effect Transistor Biosensor for DNA Hybridization Detection

This is the authors' abstract. We don't add key points for this paper.

Transition-metal dichalcogenides (TMDs), including molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 ), with appealing properties have recently become promising alternatives to graphene with semimetal and low on/off current ratio properties as the sensing channel in field-effect transistor (FET) biosensors. However, the efficiency of DNA-based FET devices strongly depends on how DNA probes are tethered to the nanomaterial channels. As against covalent attachment, simple DNA physisorption has become increasingly popular, and a DNA sequence with strong affinity for nanomaterials is still highly sought after. Recently, poly-cytosine (poly-C) DNA was found to be strongly adsorbed to many common nanomaterials, including WS 2 . Herein, a diblock DNA probe containing a (poly-C) (C15) was used to attach to a chemical vapor deposition (CVD)-grown monolayer WS 2 surface; meanwhile, the target complementary DNA (cDNA) was hybridized to the other block of the DNA probe. The biosensor developed following this strategy led to a limit of detection down to 3 aM within a concentration range spanning over approximately 7 orders of magnitude (10 –16 to 10 –9 M), which was lower than those of the previously reported TMDs and a good competitor to graphene FET DNA biosensors. Moreover, the proposed WS 2 FET DNA biosensor showed high specificity capable of distinguishing the cDNA from non-cDNA, one-base mismatched DNA, two-base mismatched DNA, and three-base mismatched DNA, making our strategy an exciting avenue for disease diagnosis. The authors are convinced that this work extends the CVD synthesis of WS 2 and its promise in biosensing application-based FETs.