A Novel Biosensing Approach: Improving SnS₂ FET Sensitivity with a Tailored Supporter Molecule and Custom Substrate

The exclusive features of two-dimensional (2D) semiconductors, such as high surface-to-volume ratios, tunable electronic properties, and biocompatibility, provide promising opportunities for developing highly sensitive biosensors. However, developing practical biosensors that can promptly detect low concentrations of target analytes remains a challenging task. Here, a field-effect-transistor comprising n-type transition metal dichalcogenide tin disulfide (SnS₂) is developed over the hexagonal boron nitride (h-BN) for the detection of streptavidin protein (Strep.) as a target analyte. A self-designed receptor based on the pyrene-lysine conjugated with biotin (PLCB) is utilized to maintain the sensitivity of the SnS₂/h-BN FET because of the π–π stacking. The detection capabilities of SnS₂/h-BN FET are investigated using both Raman spectroscopy and electrical characterizations. The real-time electrical measurements exhibit that the SnS₂/h-BN FET is capable of detecting streptavidin at a remarkably low concentration of 0.5 pm, within 13.2 s. Additionally, the selectivity of the device is investigated by measuring its response against a Cow-like serum egg white protein (BSA), having a comparative molecular weight to that of the streptavidin. These results indicate a high sensitivity and rapid response of SnS₂/h-BN biosensor against the selective proteins, which can have significant implications in several fields including point-of-care diagnostics, drug discovery, and environmental monitoring.