1T-Phase Transition Metal Dichalcogenides (MoS₂, MoSe₂, WS₂, and WSe₂) with Fast Heterogeneous Electron Transfer: Application on Second-Generation Enzyme-Based Biosensor

Two-dimensional transition metal dichalcogenides (TMDs) have been in the spotlight for their intriguing properties, including a tunable band gap and fast heterogeneous electron-transfer (HET) rate. Understandably, they are especially attractive in the field of electrochemical biosensors. In this article, HET capabilities of various TMDs (MoS₂, MoSe₂, WS₂, and WSe₂) within group VI chemically exfoliated via t-BuLi intercalation are studied and these capabilities are used in the second generation electrochemical glucose biosensor. Strikingly, tungsten dichalcogenides (WS₂ and WSe₂) exhibit superior HET properties compared to that of their molybdenum counterparts (MoS₂ and MoSe₂). When incorporated into second generation glucose biosensors, WS₂ and WSe₂ generated a higher electrochemical responses than that of MoS₂ and MoSe₂, following the same trend as expected. The commendable performance by WX₂ is attributed to the dominance of 1T phase, revealed by characterization data. The developed and optimized 1T WX₂-based biosensor achieved analytical requirements of selectivity, wide linear ranges, as well as low limits of detection and quantification. The outstanding electrochemical performances of WS₂ and WSe₂ are to be recognized, adding on to the fact that they are not decorated with any metal nanoparticles. This is imperative to showcase the real potential of two-dimensional TMDs in electrochemical biosensors.