title: Enzyme-amplified aequorin-based bioluminometric hybridization assays.
abstract: The sensitivity of aequorin-based bioluminometric hybridization assays was enhanced by introducing, enzymically, multiple aequorin labels per DNA hybrid. The target DNA was hybridized in microtiter wells with an immobilized capture probe and a digoxigenin-labeled detection probe. The hybrids were reacted with an anti-digoxigenin antibody conjugated to horseradish peroxidase. Peroxidase catalyzed the oxidation of digoxigenin-tyramine by hydrogen peroxide, resulting in the attachment of multiple digoxigenin moieties to the solid phase. Aequorin-labeled anti-digoxigenin antibody was then allowed to bind to the immobilized digoxigenins. The bound aequorin was determined by its characteristic Ca2+-triggered bioluminescence. As low as 20 fmol/L (1 amol/ well) target DNA was detected with a signal-to-background ratio of 2.7. A hybridization assay that used only aequorin-labeled anti-digoxigenin antibody without the peroxidase amplification step gave a signal-to-background ratio of 2 for 160 fmol/L target DNA. The signal enhancement of the amplified assay was in the range of 14-38 times. The analytical range of the amplified assay extended up to 2600 fmol/L. The CVs were in the range of 5.5-7.3%.
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Ontario, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Laios
authors.forename: P C
authors.initials: PC
authors.lastname: Ioannou
authors.forename: T K
authors.initials: TK
authors.lastname: Christopoulos
mesh_terms: D000331:Aequorin / Q000737:chemistry*; D001483:Base Sequence; D006735:Horseradish Peroxidase / Q000737:chemistry*; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D000331:Aequorin; D006735:Horseradish Peroxidase