Label-free plasmonic-based biosensing using a gold nanohole array chip coated with a wafer-scale deposited WS 2 monolayer.

This paper reports the fabrication, testing and obtained performance of a plasmonic sensor employing a gold (Au) nanohole array chip coated with tungsten disulphide (WS 2 ), which is then functionalized for the detection of protein-protein interactions. A key novelty is that the WS 2 was deposited as a monoatomic layer using a wafer-scale synthesis method that successfully provided a film of both high quality and uniform thickness. The deposited WS 2 film was transferred onto a Au nanohole array chip using a novel method and was subsequently functionalized with biotin. The final sensor was tested and it demonstrated efficient real-time and label-free plasmonic detection of biotin-streptavidin coupling. Specifically, compared to a standard ( i.e. uncoated) Au nanohole-based sensor, our WS 2 -coated Au nanohole array boosted the spectral shift of the resonance wavelength by ∼190%, resulting in a 7.64-fold improvement of the limit of detection (LOD).