title: Sensitive detection of biotoxoids and bacterial spores using an immunomagnetic electrochemiluminescence sensor.
abstract: Extremely sensitive detection of various biotoxoids and bacterial spores using the commercial ORIGEN analyzer was achieved by capture on antibody-conjugated micron sized magnetic beads (MBs) followed by binding of ruthenium (II) trisbipyridal chelate (Ru(bpy)2+3-labelled reporter antibodies. Immunomagnetically captured target materials were collected on a magnet. Electrochemiluminescence (ECL) was evoked from the Ru(bpy)3(2+)-tagged reporter antibodies by application of an electrical potential. Femtogram sensitivity levels were obtained for all biotoxoids tested including botulinus A, cholera beta subunit, ricin and staphylococcal enterotoxoid B by this immunomagnetic (IM)-ECL approach. An IM-ECL assay for Bacillus anthracis spores yielded a detection limit of at least 100 spores. The ECL signal was a function of analyte quantity over several orders of magnitude, but the immunological 'hook' effect at high antigen loads made quantitation impossible over a broader range. All assays were performed with a maximum combined incubation and assay time of approximately 40 min. This work demonstrates the extreme sensitivity of the IM-ECL approach for soluble and particulate antigens.
authors.affiliation: Science and Technology Corp., Edgewood, MD 21040, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Gatto-Menking
authors.forename: H
authors.initials: H
authors.lastname: Yu
authors.forename: J G
authors.initials: JG
authors.lastname: Bruno
authors.forename: M T
authors.initials: MT
authors.lastname: Goode
authors.forename: M
authors.initials: M
authors.lastname: Miller
authors.forename: A W
authors.initials: AW
authors.lastname: Zulich
mesh_terms: D001427:Bacterial Toxins / Q000032:analysis*; D015374:Biosensing Techniques; D008163:Luminescent Measurements; D008280:Magnetics; D012276:Ricin / Q000032:analysis*; D013171:Spores, Bacterial
chemical_list: D001427:Bacterial Toxins; D012276:Ricin