Fluoro immunoassay

Charbonniere LJ, Hildebrandt N, Ziessel RF, Lohmannsroben HG (2006) Lanthanides to quantum dots resonance energy transfer in time-resolved fluoro-immunoassays and luminescence microscopy. J Am Chem Soc 128 12800-12809... 

The DELFIA assay, the first effective lanthanide-based immunoassay, was developed and commercialized by the early 1980s.108-112 DELFIA (Dissociation Enhanced Lanthanide Fluoro-ImmunoAssay) is a heterogeneous assay which uses a lanthanide complex based on aminocarboxylate ligands such as EDTA, EGTA, or DTPA, linked to the antibody by reaction of appended isothiocyanate groups (e.g., complex (45)) with nucleophilic residues, particularly amines, on the protein surface (Figure 11). 

J. D. Andrade, W. M. Reichert, D. E. Gregonis, and R. A. VanWagenen, Remote fiber-optic biosensors based on evanescent-excited fluoro-immunoassay Concept and progress, IEEE Trans. Electron Devices ED-32, 1175-1179 (1985). 

Fig. 25. (A) DELFIA (Dissociation Enhanced Lanthanide Fluoro-ImmunoAssay) system. This heterogeneous immunoassay system uses a primary antibody bound to a solid support, to which a variable amount of unlabeled antigen is bound. The secondary antibody is labeled with a non-phospho-rescent lanthanide chelate, which becomes phosphorescent after dissociation from the antibody, due to the addition of an enhancement solution [which typically contains a mixture of sensitizer (typically a (1-diketonate) and micelle inducing surfactant (5). (B) Heterogeneous fluoroimmunoassay using a secondary antibody directly labeled with a phosphorescent lanthanide chelate.

Homoeopathic preparations, 51, 53 Homogeneous fluoro immunoassays, 154 Homogeneous immunoassays, 149 Homosulfaminum, 717 Homosulphanilamide, 716 Homovanillic acid, 322, 571, 702 Honvan, 975 Honvol, 975 Hordenine, 99, 661 Hordenine sulphate, 662 Hormoestrol, 657 Hormofemin, 537 Hormomed, 831 Hormonin, 830, 831 Horse plasma, phenylbutazone in, 96 Horse urine, anabolic steroids in, 95 examination of, 92 phenylbutazone in, 96 salicylic acid in, 96... 

Watson, R.A.A. Landon, J. Shaw, E.J. Smith, D.S. Polarization fluoro-immunoassay of gentamicin. Clin. Chim. Acta. 1976, 73, 51-55. 

Recent developments show that dry chemistry has also been advancing in the sector of immunological detection methods. The homogeneous immunoassay technique facilitated access to the immunological detection method. The substrate-bound fluoro-immunoassay (SLFIA) serves as an example for the determination of theophylline concentration. However, the radial partition immunoassay paved the way for determining the concentration of numerous drugs and hormones. 

Among this variety of immunosensor systems, two optical immunosensor devices for environmental applications RIANA and AWACSS are especially noteworthy. These immunosensors are based on solidphase fluoro-immunoassays combined with an optical transducer chip chemically modified with an analyte derivate. The RIANA immunosensor was applied successfully in a variety of environmental applications (Mallat et al., 1999 Rodriguez-Mozaz et al., 2004b). The other new analytical system AWACSS has... 

The reaction is not as simple as it appears though, because a labelled substance (tracer) is needed to facilitate the detection of the Ab-Ag binding event. These labels can be radioisotopes (radio immunoassay (RIA), not used in environmental analysis), fluorophores (fluoro immunoassay (FIA)) or enzymes (enzyme immunoassay (EIA)). Therefore a competition of the Ag with the label (L) is involved, and is defined by the association and dissociation rate constants ka2 and kd2 (Equation (3.3.2)) ... 

Among homogeneous fluoroimmunoassays based on conventional fluorimetry, substrate-labeled fluoro-immunoassay is another alternative for both hapten and protein determination using a fluorescent label. As in other homogeneous competitive immunoassays, the sensitivity is limited by the serum background fluorescence and the limited amount of tracer that can be used. 

Immunoassays represent very selective and sensitive techniques that have found application in several areas such as clinical chemistry, bioanalysis, pharmaceutical analysis, toxicological analysis, and environmental analysis. The first immunoassays developed were radioimmunoassays, which are very sensitive however, one drawback is the need to work radiochemicals. To circumvent the drawbacks, other labels such as enzymes in combination with photometric measurement have been introduced, however, at the expense of sensitivity. With the development of fluoro-immunoassays (FIAs) an improvement in sensitivity was obtained and by introducing chemiluminescence in immunoassays, a sensitivity equivalent to radioimmunoassays was achieved. In this article, different variations and techniques of luminescence immunoassays are described. 

The application of the Horrock and Sudnick equation to the terbium complex of ligand 6, reveals that only one water molecule is still coordinated to the complexed cation. Consequently, the lifetime (t = 1.5 sec) and the luminescence quantum yield (< > = 0.2) of this complex are very high and make it attractive for applications as luminescent probes in time-resolved fluoro-immunoassays (TR-FIA). " In order to lurther improve the luminescence properties of these ligands by increasing their molar absorbitivities (e) we have synthesized calix[4]arenes (e.g. 7) with four bipyridines or phenantrolines at the lower rim. A significant increase in the value of e of these derivatives has been... 

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