An acetylcholinesterase biosensor based on graphene–gold nanocomposite and calcined layered double hydroxide

In this study, a novel acetylcholinesterase-based biosensor was fabricated. Acetylcholinesterase (AChE) was immobilized onto a glassy carbon electrode (GCE) with the aid of Cu–Mg–Al calcined layered double hydroxide (CLDH). CLDH can provide a bigger effective surface area for AChE loading, which could improve the precision and stability of AChE biosensor. However, the poor electroconductibility of CLDHs could lead to the low sensitivity of AChE biosensor. In order to effectively compensate the disadvantages of CLDHs, graphene–gold nanocomposites were used for improving the electron transfer rate. Thus, the graphene–gold nanocomposite (GN-AuNPs) was firstly modified onto the GCE, and then the prepared CLDH-AChE composite was immobilized onto the modified GCE to construct a sensitive AChE biosensor for pesticides detection. Relevant parameters were studied in detail and optimized, including the pH of the acetylthiocholine chloride (ATCl) solution, the amount of AChE immobilized on the biosensor and the inhibition time governing the analytical performance of the biosensor. The biosensor detected chlorpyrifos at concentrations ranging from 0.05 to 150 μg/L. The detection limit for chlorpyrifos was 0.05 μg/L.

The CLDHs as enzyme immobilization matrix was applied to construct highly performance-enhanced AChE biosensor. Graphene–gold nanocomposite was dropped on the surface of the glassy carbon electrode, and greatly improved the conductivity of the modified electrode. Amperometric experiments were performed on a workstation by adopt a conventional three electrode system. The obtained biosensor based on enzyme inhibition for determination of pesticide showed a wide linear range and low detection limit.Figure optionsDownload as PowerPoint slide