A highly sensitive and rapid organophosphate biosensor based on enhancement of CdS-decorated graphene nanocomposite

This work reports a rapid and sensitive organophosphates (OPs) amperometric biosensor based on acetylcholinesterase (AChE) immobilized on CdS-decorated graphene (CdS-G) nanocomposite. The as-prepared biosensor shows high affinity to acetylthiocholine (ATCl) with a Michaelis-Menten constant (K(m)) value of 0.24 mM. A rapid inhibition time (2 min) is obtained due to the integration of the CdS-G nanocomposite. Based on the inhibition of OPs on the enzymatic activity of the immobilized AChE, and used carbaryl as the model compound, the resulting biosensor exhibits excellent performance for OPs detection including good reproducibility, acceptable stability, and a reliable linear relationship between the inhibition and log[carbaryl] from 2 ng mL(-1) up to 2 mu g m L(-1) with a detection limit of 0.7 ng mL(-1), which provides a new promising tool for analysis of enzyme inhibitors. (C) 2011 Elsevier B.V. All rights reserved.