title: Development of acetylcholinesterase silica sol-gel immobilized biosensor--an application towards oxydemeton methyl detection.
abstract: An amperometric silica sol-gel film immobilized biosensor doped with acetylcholinesterase was fabricated in the laboratory finding application in organophosphate detection based on enzyme inhibition. The substrate used was acetylthiocholine chloride and thiocholine released from the enzymatic hydrolysis was electrochemically oxidized giving larger anodic current at 0.5-0.6 V (versus Ag/AgCl reference). The dependencies of the current response on pH, enzyme loading and thermal stability of the developed biosensor were evaluated. The analytical performance of enzyme electrode towards substrate and inhibitor was investigated. Oxydemeton methyl was taken as a model compound for the inhibition studies. Linear calibration for oxydemeton methyl was obtained in the range of 2-200 ppb under the optimized conditions following an incubation time of 20 min. Treatment of the inhibited enzyme with pyridine-2-aldehyde restored 92% of its original activity. The sensor stored at -20 degrees C had a good storage and operational stability retaining 85% of its original activity for 60 successive measurements.
authors.affiliation: Department of Chemistry, Electrochemical Research Laboratories, Sri Venkateswara University, Tirupati 517 502, India.
authors.forename: K
authors.initials: K
authors.lastname: Anitha
authors.forename: S Venkata
authors.initials: SV
authors.lastname: Mohan
authors.forename: S Jayarama
authors.initials: SJ
authors.lastname: Reddy
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007306:Insecticides / Q000032:analysis; D009946:Organothiophosphorus Compounds / Q000032:analysis*; D044367:Phase Transition; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D007306:Insecticides; D009946:Organothiophosphorus Compounds; D058428:Silica Gel; D012822:Silicon Dioxide; C026086:methyl demeton; D000110:Acetylcholinesterase