Ultra-thin bimetallic alloy nanowires with porous architecture/monolayer MoS nanosheet as a highly sensitive platform for the electrochemical assay of hazardous omethoate pollutant.

A novel electrochemical biosensor was designed for sensitive detection of organophosphate pesticides based on three-dimensional porous bimetallic alloy architecture with ultrathin nanowires (PdCo NWs, PdCu NWs, PdNi NWs) and monolayer MoS nanosheet (m-MoS). The bimetallic alloy NWs/m-MoS nanomaterials were used as a sensing platform for electrochemical analysis of omethoate, a representative organophosphate pesticide, via acetylcholinesterase inhibition pathway. We demonstrated that all three bimetallic alloy NWs enhanced electrochemical responses of enzymatic biosensor, benefited from bimetallic synergistic action and porous structure. In particular, PdNi NWs outperformed other two bimetallic alloy. Moreover, PdNi NWs/m-MoS as an electronic transducer is superior to the corresponding biosensor in the absence of monolayer MoS nanosheet, which arise from synergistic signal amplification effect between different components. Under optimized conditions, the developed biosensor on the basis of PdNi NWs/m-MoS shows outstanding performance for the electrochemical assay of omethoate, such as a wide linear range (10 M∼10 M), a low detection limit of 0.05 pM at a signal-to-noise ratio of 3, high sensitivity and long-time stability. The results demonstrate that bimetallic alloy NWs/m-MoS nanocomposites could be excellent transducers to promote electron transfer for the electrochemical reactions, holding great potentials in the construction of current and future biosensing devices.