title: Immobilization of acetylcholineesterase-choline oxidase on a gold-platinum bimetallic nanoparticles modified glassy carbon electrode for the sensitive detection of organophosphate pesticides, carbamates and nerve agents.
abstract: A novel, highly sensitive amperometric biosensor, based on electrodeposition of gold-platinum bimetallic nanoparticles onto 3-aminopropyltriethoxy silane modified glassy carbon electrode for the detection of paraoxon ethyl, aldicarb, and sarin has been developed. The biosensor consists of acetylcholineesterase (AChE)/choline oxidase (ChOx) immobilized by cross-linking with glutaraldehyde on a modified electrode. The properties of nanoparticles modified electrodes are characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), cyclic voltammograms (CVs) and electrochemical impedance spectroscopy (EIS). The synergistic action of Au and Pt nanoparticles showed excellent electrocatalytic activity with low applied potential for the detection of hydrogen peroxide (H(2)O(2)). The IC(50) and inhibition rate constant (K(i)) values were determined for the inhibitors using immobilized enzymes on modified electrode and the data were compared by spectrophotometric determination of these kinetic parameters using free enzymes in solution. Paraoxon ethyl, sarin, and aldicarb could be detected up to 150-200nM, 40-50nM, and 40-60 microM respectively at 30-40% inhibition level of AChE enzyme and followed linearity in wide range concentration.
authors.affiliation: Defence Research and Development Establishment, Gwalior 474002, India. sanjayupad@rediffmail.com
authors.forename: Sanjay
authors.initials: S
authors.lastname: Upadhyay
authors.forename: Golime Rama
authors.initials: GR
authors.lastname: Rao
authors.forename: Mukesh K
authors.initials: MK
authors.lastname: Sharma
authors.forename: Bijoy K
authors.initials: BK
authors.lastname: Bhattacharya
authors.forename: Vepa K
authors.initials: VK
authors.lastname: Rao
authors.forename: R
authors.initials: R
authors.lastname: Vijayaraghavan
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D000429:Alcohol Oxidoreductases / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D002219:Carbamates / Q000032:analysis*; D002244:Carbon / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D009498:Neurotoxins / Q000032:analysis*; D010755:Organophosphates / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D010984:Platinum / Q000737:chemistry*
chemical_list: D002219:Carbamates; D004800:Enzymes, Immobilized; D009498:Neurotoxins; D010755:Organophosphates; D010575:Pesticides; D010984:Platinum; D002244:Carbon; D006046:Gold; D000429:Alcohol Oxidoreductases; C019888:choline oxidase; D000110:Acetylcholinesterase