Acetylcholinesterase biosensor based on 3-carboxyphenylboronic acid/reduced graphene oxide–gold nanocomposites modified electrode for amperometric detection of organophosphorus and carbamate pesticides

A novel amperometric biosensor based on immobilizing acetylcholinesterase on 3-carboxyphenylboronic/reduced graphene oxide–gold nanocomposites modified electrode was developed for the detection of organophosphorus and carbamate pesticides. Acetylcholinesterase was successfully immobilized on the electrode with relatively high activity by the specific binding between the boronic acid group of 3-carboxyphenylboronic and the glycosyl of acetylcholinesterase. The biosensor enjoyed good sensitivity owing to the excellent properties of gold nanoparticles and reduced graphene oxide, which promoted electron transfer reaction and enhanced the electrochemical response. Parameters affecting the biosensor response such as pH, applied potential, enzyme loading and inhibition time were optimized. Based on the inhibition of an organophosphorus insecticide on the enzymatic activity of AChE, organophosphorus and carbamate pesticides were determined with satisfactory results in the presence of acetylthiocholine chloride as a substrate. Moreover, the fabricated biosensor had good repeatability and high stability.