title: Acetylcholinesterase biosensor based on multi-walled carbon nanotubes-SnO₂-chitosan nanocomposite.
abstract: A sensitive amperometric acetylcholinesterase (AChE) biosensor was developed based on the nanocomposite of multi-walled carbon nanotubes (MWCNTs), tin oxide (SnO2) nanoparticles and chitosan (CHIT). Acetylcholinesterase (AChE) and Nafion were immobilized onto the nanocomposite film to prepare AChE biosensor for pesticide residues detection. The morphologies and electrochemistry properties of the surface modification were investigated using cyclic voltammetry, differential pulse voltammetry, and scanning electron microscopy, respectively. Compared with individual MWCNTs-CHIT, SnO2-CHIT and bare gold electrode, this nanocomposite showed the most obvious electrochemical signal in the presence of [Fe(CN)6](3-/4-) as a redox couple. Incorporating MWCNTs and SnO2 into 0.2% CHIT solution can promote electron transfer, enhance the electrochemical response, and improve the microarchitecture of the electrode surface. All variables involved in the preparation process and analytical performance of the biosensor were optimized. Under optimized conditions, the AChE biosensor exhibited a wide linear range from 0.05 to 1.0 × 10(5 )μg/L and with a detection limit for chlorpyrifos was 0.05 μg/L. Based on the inhibition of pesticides on the AChE activity, using chlorpyrifos as model pesticide, the proposed biosensor exhibited a wide range, low detection limit, good reproducibility, and high stability. Using cabbages, lettuces, leeks, and pakchois as model samples, acceptable recovery of 98.7-105.2% was obtained. The proposed method was proven to be a feasible quantitative method for chlorpyrifos analysis, which may open a new door ultrasensitive detection of chlorpyrifos residues in vegetables and fruits.
authors.affiliation: School of Agriculture and Food Engineering, Shandong University of Technology, NO. 12, Zhangzhou Road, Zibo, 255049, Shandong Province, People's Republic of China.
authors.forename: Dongfei
authors.initials: D
authors.lastname: Chen
authors.forename: Xia
authors.initials: X
authors.lastname: Sun
authors.forename: Yemin
authors.initials: Y
authors.lastname: Guo
authors.forename: Lu
authors.initials: L
authors.lastname: Qiao
authors.forename: Xiangyou
authors.initials: X
authors.lastname: Wang
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D048271:Chitosan / Q000737:chemistry*; D004390:Chlorpyrifos / Q000032:analysis* / Q000737:chemistry; D002800:Cholinesterase Inhibitors / Q000032:analysis / Q000737:chemistry; D003217:Conductometry / Q000295:instrumentation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008839:Microelectrodes; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017971:Tin Compounds / Q000737:chemistry*
chemical_list: D002800:Cholinesterase Inhibitors; D017971:Tin Compounds; D048271:Chitosan; D000110:Acetylcholinesterase; D004390:Chlorpyrifos; C045358:stannic oxide