A fluorescence-based biosensor for the detection of organophosphate pesticides and chemical warfare agents

Recently elevated concerns of environmental contamination with organophosphate (OP) insecticides and the possible use of OP nerve agents by terrorists have spurred interest in developing more accurate and sensitive methods for field detection and discrimination of these neurotoxic agents. The analysis of OP neurotoxins typically requires sophisticated equipment, extensive sample preparation that is labor-intensive and prolonged processing time to validate the results. Therefore, a rapid, fiber-optic biosensor assay for the direct detection of organophosphates was developed in this study. The biorecognition element is an enzyme, organophosphate hydrolase (OPH), which was conjugated with both biotin, to anchor it and a fluorescence reporter carboxynaphthofluorescein (CNF). Avidin was attached to the polystyrene waveguide surface of a fluorescent detector, and the OPH–CNF–biotin biosensor conjugate was bound to the avidin. The recognition element (OPH) and reporter (CNF) molecules were designed to entertain OP samples with concentrations of neurotoxin as low as 0.05 μM. Quantitative detection could be determined from 1 to 800 μM for paraoxon and from 2 to 400 μM for DFP. In addition, the system could also be used to provide continual remote monitoring and spectral fluorescent notification.