title: Development of a novel optical biosensor for detection of organophosphorus pesticides based on methyl parathion hydrolase immobilized by metal-chelate affinity.
abstract: We have developed a novel optical biosensor device using recombinant methyl parathion hydrolase (MPH) enzyme immobilized on agarose by metal-chelate affinity to detect organophosphorus (OP) compounds with a nitrophenyl group. The biosensor principle is based on the optical measurement of the product of OP catalysis by MPH (p-nitrophenol). Briefly, MPH containing six sequential histidines (6 × His tag) at its N-terminal was bound to nitrilotriacetic acid (NTA) agarose with Ni ions, resulting in the flexible immobilization of the bio-reaction platform. The optical biosensing system consisted of two light-emitting diodes (LEDs) and one photodiode. The LED that emitted light at the wavelength of the maximum absorption for p-nitrophenol served as the signal light, while the other LED that showed no absorbance served as the reference light. The optical sensing system detected absorbance that was linearly correlated to methyl parathion (MP) concentration and the detection limit was estimated to be 4 μM. Sensor hysteresis was investigated and the results showed that at lower concentration range of MP the difference got from the opposite process curves was very small. With its easy immobilization of enzymes and simple design in structure, the system has the potential for development into a practical portable detector for field applications.
authors.affiliation: Shenzhen R&D Key Laboratory of Exotic Pest Detection Technology, Animal & Plant Inspection and Quarantine Technical Center, Shenzhen Entry-Exit Inspection and Quarantine Burea, 1011 Fuqiang Road, Shenzhen 518045, China. lanwshao@yahoo.com.cn
authors.forename: Wensheng
authors.initials: W
authors.lastname: Lan
authors.forename: Guoping
authors.initials: G
authors.lastname: Chen
authors.forename: Feng
authors.initials: F
authors.lastname: Cui
authors.forename: Feng
authors.initials: F
authors.lastname: Tan
authors.forename: Ran
authors.initials: R
authors.lastname: Liu
authors.forename: Maolidan
authors.initials: M
authors.lastname: Yushupujiang
mesh_terms: D015374:Biosensing Techniques; D002614:Chelating Agents / Q000737:chemistry; D002846:Chromatography, Affinity; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D008670:Metals / Q000737:chemistry; D008743:Methyl Parathion / Q000032:analysis*; D009532:Nickel / Q000737:chemistry; D009571:Nitrilotriacetic Acid / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D004800:Enzymes, Immobilized; C471213:His-His-His-His-His-His; D008670:Metals; D009842:Oligopeptides; D009943:Organophosphorus Compounds; D010575:Pesticides; D011994:Recombinant Proteins; D008743:Methyl Parathion; D006639:Histidine; D009532:Nickel; D010744:Phosphoric Monoester Hydrolases; D009571:Nitrilotriacetic Acid