title: A novel acetylcholinesterase biosensor based on carboxylic graphene coated with silver nanoparticles for pesticide detection.
abstract: A novel acetylcholinesterase (AChE) biosensor based on Ag NPs, carboxylic graphene (CGR) and Nafion (NF) hybrid modified glass carbon electrode (GCE) has been successfully developed. Ag NPs-CGR-NF possessed predominant conductivity, catalysis and biocompatibility and provided a hydrophilic surface for AChE adhesion. Chitosan (CS) was used to immobilize AChE on the surface of Ag NPs-CGR-NF/GCE to keep the AChE activities. 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 133 μM, which was then oxidized to produce a detectable and fast response. Under optimum conditions, the biosensor detected chlorpyrifos and carbaryl at concentrations ranging from 1.0×10(-13) to 1×10(-8) M and from 1.0×10(-12) to 1×10(-8) M. The detection limits for chlorpyrifos and carbaryl were 5.3×10(-14) M and 5.45×10(-13) M, respectively. The developed biosensor exhibited good sensitivity, stability, reproducibility and low cost, thus providing a promising tool for analysis of enzyme inhibitors. This study could provide a simple and effective immobilization platform for meeting the demand of the effective immobilization enzyme on the electrode surface.
authors.affiliation: School of Chemical Science and Engineering, Yunnan University, Kunming 650091, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemical Science and Engineering, Yunnan University, Kunming 650091, China. Electronic address: wangc166163@sina.com.
authors.forename: Guangcan
authors.initials: G
authors.lastname: Wang
authors.affiliation: School of Chemical Science and Engineering, Yunnan University, Kunming 650091, China.
authors.forename: Canpeng
authors.initials: C
authors.lastname: Li
authors.affiliation: School of Physical Science and Technology, Yunnan University, Kunming 650091, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: School of Chemical Science and Engineering, Yunnan University, Kunming 650091, China.
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.affiliation: School of Chemical Science and Engineering, Yunnan University, Kunming 650091, China.
authors.forename: Long
authors.initials: L
authors.lastname: Yang
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation*; D002264:Carboxylic Acids / Q000737:chemistry; D002800:Cholinesterase Inhibitors / Q000032:analysis / Q000737:chemistry; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010575:Pesticides / Q000032:analysis* / Q000737:chemistry; D012834:Silver / Q000737:chemistry*
chemical_list: D002264:Carboxylic Acids; D002800:Cholinesterase Inhibitors; D010575:Pesticides; D012834:Silver; D006108:Graphite; D000110:Acetylcholinesterase
keywords: Acetylcholinesterase biosensor; Carboxylic graphene; Nafion; Silver nanoparticles