Superior peroxidase mimetic activity of tungsten disulfide nanosheets/silver nanoclusters composite: Colorimetric, fluorometric and electrochemical studies

Developing a novel peroxidase nano-mimetic is a challenging research topic in biosensing field. Herein, WS₂ nanosheets (WS₂ NS) decorated with silver nanoclusters (AgNCs) was introduced as a new nanocomposite with improved peroxidase mimetic behavior. WS₂ NS/AgNCs nanocomposite was synthesized by simple chemical reduction of silver cations in the presence of WS₂ NS. The enhanced catalytic activity of nanocomposite in chemical and electrochemical reduction of H₂O₂ was studied using colorimetry, fluorometry and electrochemical techniques. Attaching the AgNCs on the surface of WS₂ NS effectively improved the catalytic activity of these nanosheets, which may be connected to the difference of the Fermi energy levels of coupled nanomaterial. The unequal Fermi levels cause charge separation between two phases creating highly active sites on the interface of coupled nanomaterial. Moreover, the new mimetic nanocomposite was applied for the analysis of glucose in blood, based on its enzymatic oxidation using glucose oxidase and then, on the measurement of produced H₂O₂ by sensitive fluorescence detection system. In optimum condition, a linear association was found between the generated fluorescence intensity and glucose logarithmic concentration in the range of 0.05–400 µM, and the limit of detection (3S/m) was 21 nM.