title: Optical organophosphorus biosensor consisting of acetylcholinesterase/viologen hetero Langmuir-Blodgett film.
abstract: The fiber-optic biosensor consisting of an acetylcholinesterase (AChE)-immobilized Langmuir-Blodgett (LB) film was developed to detect organophosphorus compounds in contaminated water. The sensing scheme was based on the decrease of yellow product, o-nitrophenol, from a colorless substrate, o-nitrophenyl acetate, due to the inhibition by organophosphorus compounds on AChE. Absorbance change of the product as the output of enzyme reaction was detected and the light was guided through the optical fibers. The enzyme portion of the sensor system was fabricated by the LB technique for formation of the enzyme film. AChE-immobilized LB film was formed by adsorbing the enzyme molecules onto a viologen monolayer using the electrostatic force. The proposed kinetics for irreversible inhibition of organophosphorus compounds on AChE agreed well with the experimental data. The surface topography of AChE-immobilized LB film was investigated by atomic force microscope (AFM). The immobilized AChE had the maximum activity at pH 7. The proposed biosensor could successfully detect the organophosphorus compounds up to 2 ppm and the response time to steady signal of the sensor was about 10 min.
authors.affiliation: Department of Chemical Engineering, Sogang University, C.P.O. Box 1142, Seoul 100-611, South Korea. jwchoi@ccs.sogang.ac.kr
authors.forename: J W
authors.initials: JW
authors.lastname: Choi
authors.forename: Y K
authors.initials: YK
authors.lastname: Kim
authors.forename: I H
authors.initials: IH
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Min
authors.forename: W H
authors.initials: WH
authors.lastname: Lee
mesh_terms: D000110:Acetylcholinesterase; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004800:Enzymes, Immobilized; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D055095:Optics and Photonics / Q000295:instrumentation; D009943:Organophosphorus Compounds / Q000032:analysis*; D014755:Viologens; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D004800:Enzymes, Immobilized; D009943:Organophosphorus Compounds; D014755:Viologens; D014874:Water Pollutants, Chemical; D000110:Acetylcholinesterase