title: Detection of botulinum toxin using an evanescent wave immunosensor.
abstract: Using fluorescein isothiocyanate (FITC)-streptavidin, quartz fibre-immobilized antibody (FiAb) and the evanescent wave component of a light beam, detection of Botulinum Toxin-B (BoTX) is described. Exposure of 3-aminopropyltriethoxysilane/glutaraldehyde (APTS/GA) treated quartz fibres to increasing amounts of anti-BoTX Ab indicated toxin binding to increase in a linear fashion up to approximately 125 ng added Ab. Quantitation of bound BoTX and FiAb by Dot-Blot analysis using avidin-Horseradish peroxidase (HRP) conjugation indicated the presence of 0.27 and 0.67 pmoles, respectively. Inclusion of nonbiotinylated BoTX in sampling mixtures reduced fluorescence in a dose-dependent manner over a narrow concentration range (0-300 ng). Exposure of FiAb to a variety of venoms resulted in no reduction of BoTX binding suggesting detection of BoTX via immobilized anti-BoTX Ab to be very specific.
authors.affiliation: Brain Research Laboratory of Biochemistry, University of Texas at San Antonio 78249.
authors.forename: P
authors.initials: P
authors.lastname: Kumar
authors.forename: J T
authors.initials: JT
authors.lastname: Colston
authors.forename: J P
authors.initials: JP
authors.lastname: Chambers
authors.forename: E D
authors.initials: ED
authors.lastname: Rael
authors.forename: J J
authors.initials: JJ
authors.lastname: Valdes
mesh_terms: D015374:Biosensing Techniques; D001905:Botulinum Toxins / Q000032:analysis*; D005336:Fiber Optic Technology; D016650:Fluorescein-5-isothiocyanate; D008027:Light; D011791:Quartz
chemical_list: D011791:Quartz; D001905:Botulinum Toxins; D016650:Fluorescein-5-isothiocyanate