Development of a biosensor based on immobilization of acetylcholinesterase on NiO nanoparticles-carboxylic graphene-nafion modified electrode for detection of pesticides.

A sensitive amperometric acetylcholinesterase (AChE) biosensor based on NiO nanoparticles (NiO NPs), carboxylic graphene (CGR) and nafion (NF) modified glassy carbon electrode (GCE) has been developed. NiO NPs-CGR-NF nanocomposites with excellent conductivity, catalysis and biocompatibility offered an extremely hydrophilic surface for AChE adhesion. The AChE biosensor showed favorable affinity to acetylthiocholine chloride (ATCl) and could catalyze the hydrolysis of ATCl with an apparent Michaelis-Menten constant value of 135 μM. Under optimum conditions, the biosensor detected methyl parathion and chlorpyrifos in the linear range from 1.0 × 10(-13) to 1 × 10(-10)M and from 1.0 × 10(-10) to 1 × 10(-8)M with the detection limits 5 × 10(-14)M. The biosensor detected carbofuran in the linear range from 1.0 × 10(-12) to 1 × 10(-10)M and from 1.0 × 10(-10) to 1 × 10(-8)M with the detection limit of 5 × 10(-13)M. The developed biosensor exhibited good sensitivity, stability and reproducibility, thus providing a promising tool for analysis of enzyme inhibitors.