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Sensors (Basel). 2012;12(7):8477-90. Epub 2012 Jun 25.

Development of a novel optical biosensor for detection of organophosphorus pesticides based on methyl parathion hydrolase immobilized by metal-chelate affinity.

Author information

1
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

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.

KEYWORDS:

metal-chelate affinity; methyl parathion hydrolase; optical biosensor; organophosphorus compound

PMID:
23012501
PMCID:
PMC3444059
DOI:
10.3390/s120708477
[Indexed for MEDLINE]
Free PMC Article
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