Fluorescence Immunofiltration Assay of Brucella Melitensis.
Abstract
Detection of biological materials can be carried out using a silicon-based light addressable potentiometric (LAP) sensor in conjunction with filtration-capture immunoassay. The immunoassay employs a fluorescein-conjugated antibody directed against a target antigen plus a second urease-labelled antibody directed against fluorescein. The assay system is useful for measuring protein, virus and bacteria in aqueous samples and has been employed in automated prototypes of the Biochemical Detector. Although fluorescein is employed in the assay as a binding site for the signal-generating urease-labelled antibody, it is a highly fluorescent molecule and has signal-generating capacity of its own. In the present work a comparison was made of the sensitivity of detecting filtration-captured bacteria, Brucella melitensis, via a LAP sensor assay and via fluorescence derived from fluorescein-labelled antibodies. Limits of detection for Brucella melitensis were 0.5 ng per well for the LAP sensor and 10 ng per well for the fluorescence detection. Although the fluorescence system was not as sensitive as the potentiometric assay, the results are nonetheless encouraging since the optical configuration of the fluorescence assay was not optimized. The fluorescence-based assay offers a number of advantages over the potentiometric sensor for an automated Biochemical Detector, including speed of measurement, greater stability of reagents and absence of substrate fluidics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1995
- Accession Number
- ADA292325
Entities
People
- H. G. Thompson
- John G. Hall
- William E. Lee
Organizations
- Defence Research and Development Canada