Biocompatible ZrO2- reduced graphene oxide immobilized AChE biosensor for chlorpyrifos detection

Abstract

Based on Acetylcholinestrase (AChE) inhibition, a novel biosensing electrode involving Reduced Graphene Oxide (RGO) supported Zirconium Oxide (ZrO2/RGO) nanoparticles is fabricated for Chlorpyrifos (pesticide) detection. AChE/ZrO2/RGO biosensor when used for pesticide detection, exhibited high sensitivity towards Chlorpyrifos. Typically AChE/ZrO2/RGO biosensing electrode is capable of detecting Chlorpyrifos concentration as low as 10−13M (with 28% enzyme inhibition). Furthermore the enzyme inhibition is remarkable high (>70%) in case of high Chlorpyrifos concentration (up to 10−4M). Our results indicate that AChE/ZrO2/RGO is an efficient and biocompatible electrode that can be used for Chlorpyrifos detection in ultra low concentrations. Electrochemical sensing response of AChE/ZrO2/RGO sensor revealed two different linear ranges of chlorpyrifos detection. The first linear response was observed from 10−13M to 10−9M whereas the second linear range was observed between 10−9M to 10−4M revealing complete saturation of enzyme active sites by Chlorpyrifos. Ameperometric response of AChE/ZrO2/RGO electrode demonstrates constant decrease in the current with respect to increase in the Chlorpyrifos concentration.