title: A rapid reusable fiber optic biosensor for detecting cocaine metabolites in urine.
abstract: Analyte 2000, a four-channel fiber optic biosensor (FOB), was used for analysis of cocaine and its metabolites (COC) in human urine using a competitive fluorescence immunoassay. Binding of antibenzoylecgonine monoclonal antibody (mAb) to the casein-benzoylecgonine Ag-coated, tapered optical fibers was inhibited by COC. Bound mAb, which inversely correlated with COC concentration, was quantitated by fluorescence produced by evanescent excitation of bound cyanine dye-tagged antimouse antibody (CY5-Ab). The effective concentration range of benzoylecgonine (BE) for inhibiting the fluorescent signals was 0.75-50 ng/mL, with IC50 of 9.0 ng/mL. This FOB had similar affinities for BE, cocaine, and cocaethylene, but very low affinities for ecgonine and ecgonine methyl ester. A sensitivity of 100% and a specificity of 96% were achieved when 54 human urine specimens were analyzed by FOB (cutoff, 300 ng/mL COC) and GC-MS (cutoff, 150 ng/mL BE). All results were in agreement except for one positive FOB result with a GC-MS BE concentration of 148 ng/mL. In addition, regeneration and reuse of the fiber for multiple analyses were performed successfully with no carryover from specimens containing high COC concentrations to specimens containing low COC concentrations.
authors.affiliation: Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, Baltimore 21201, USA.
authors.forename: N
authors.initials: N
authors.lastname: Nath
authors.forename: M
authors.initials: M
authors.lastname: Eldefrawi
authors.forename: J
authors.initials: J
authors.lastname: Wright
authors.forename: D
authors.initials: D
authors.lastname: Darwin
authors.forename: M
authors.initials: M
authors.lastname: Huestis
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D003042:Cocaine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000652:urine*; D018765:Dopamine Uptake Inhibitors / Q000032:analysis; D005336:Fiber Optic Technology / Q000379:methods*; D016231:Fluorescence Polarization Immunoassay; D006801:Humans; D009294:Narcotics / Q000032:analysis* / Q000652:urine; D055100:Optical Fibers; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014556:Urine / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D018765:Dopamine Uptake Inhibitors; D009294:Narcotics; C005618:benzoylecgonine; C066444:cocaethylene; D003042:Cocaine