title: Immobilization of rat brain acetylcholinesterase on ZnS and poly(indole-5-carboxylic acid) modified Au electrode for detection of organophosphorus insecticides.
abstract: A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds has been constructed, based on rat brain acetylcholinesterase (AChE) immobilized onto nanocomposite of ZnS-nanoparticles (ZnSNPs) and poly(indole-5-carboxylic acid) electrodeposited on Au electrode. In the presence of acetylthiocholine chloride (ATCl) as a substrate, ZnSNPs promoted electron transfer reactions at a lower potential and catalyzed electrochemical oxidation of enzymatically formed thiocholine, thus increasing detection sensitivity. Under optimum conditions (phosphate buffer, pH 7.5 and 30°C), the inhibition of AChE by malathion and chlorpyrifos was proportional to their concentrations in the range, 0.1-50nM and 1.5-40nM, respectively. The biosensor determined malathion and chlorpyrifos in spiked tap water samples with a acceptable accuracy (95-100%). The enzyme electrode had long-storage stability (50% retention of initial activity within 2 months, when stored at 4°C).
authors.affiliation: Department of Biochemistry, M. D. University, Rohtak 124 001, Haryana, India.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Chauhan
authors.forename: Jagriti
authors.initials: J
authors.lastname: Narang
authors.forename: C S
authors.initials: CS
authors.lastname: Pundir
mesh_terms: D000110:Acetylcholinesterase; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D004390:Chlorpyrifos / Q000032:analysis; D055664:Electrochemical Techniques; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D058851:GPI-Linked Proteins; D006046:Gold; D007211:Indoles; D007306:Insecticides / Q000032:analysis*; D008294:Malathion / Q000032:analysis; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry / Q000648:ultrastructure; D009943:Organophosphorus Compounds / Q000032:analysis*; D011108:Polymers; D051381:Rats; D013440:Sulfides; D014874:Water Pollutants, Chemical / Q000032:analysis; D017967:Zinc Compounds
chemical_list: D004800:Enzymes, Immobilized; D058851:GPI-Linked Proteins; D007211:Indoles; D007306:Insecticides; D009943:Organophosphorus Compounds; D011108:Polymers; D013440:Sulfides; D014874:Water Pollutants, Chemical; D017967:Zinc Compounds; C514680:poly(indole-5-carboxylic acid); D006046:Gold; D000110:Acetylcholinesterase; C548246:Ache protein, rat; D004390:Chlorpyrifos; C031238:zinc sulfide; D008294:Malathion