Growth of large-scale MoS2 nanosheets on double layered ZnCo2O4 for real-time in situ H2S monitoring in live cells

Abstract

There is an urgent need to develop in situ sensors that monitor the continued release of H₂S from biological systems to understand H₂S-related pathology and pharmacology. For this purpose, we have developed a molybdenum disulfide supported double-layered zinc cobaltite modified carbon cloth electrode (MoS₂–ZnCo₂O₄–ZnCo₂O₄) based electrocatalytic sensor. The results of our study suggest that the MoS₂–ZnCo₂O₄–ZnCo₂O₄ electrode has excellent electrocatalytic ability to oxidize H₂S at physiological pH, in a minimized overpotential (+0.20 vs. Ag/AgCl) with an amplified current signal. MoS₂ grown on double-layered ZnCo₂O₄ showed relatively better surface properties and electrochemical properties than MoS₂ grown on single-layered ZnCo₂O₄. The sensor delivered excellent analytical parameters, such as low detection limit (5 nM), wide linear range (10 nM–1000 μM), appreciable stability (94.3%) and high selectivity (2.5-fold). The practicality of the method was tested in several major biological fluids. The electrode monitors the dynamics of bacterial H₂S in real-time for up to 5 h with good cell viability. Our research shows that MoS₂–ZnCo₂O₄–ZnCo₂O₄/carbon cloth is a robust and sensitive electrode to understand how bacteria seek to adjust their defense strategies under exogenously induced stress conditions.