Immunoassay techniques, based fluorescence

See also Chemiluminescence Overview. Chiroptical Analysis. Derivatizatlon of Analytes. Enzymes Enzyme-Based Assays. Fluorescence Overview Ciinicai and Drug Appiications. Gas Chromatography Coiumn Technoiogy Mass Spectrometry. Immunoassays Overview. Immunoassays, Applications Clinical. Immunoassays, Techniques Enzyme Immunoassays Luminescence Immunoassays. Infrared Spectroscopy Overview. Liquid Chromatography Column Technology Normal... 

See also. Chemiluminescence Oven/iew. Derivatiza-tion of Analytes. Electrophoresis Oven/iew. Enzymes Oven/iew Immobiiized Enzymes Enzyme-Based Eiec-trodes Enzymes in Physioiogicai Sampies Industriai Products and Processes Enzyme-Based Assays. Fluorescence Clinical and Drug Applications. Immunoassays Overview Production of Antibodies. Immunoassays, Applications Clinical Food Forensic. Immunoassays, Techniques Radioimmunoassays Enzyme Immunoassays Luminescence Immunoassays. Mass Spectrometry Polymerase Chain Reaction Products. Nucleic Acids Chromatographic and Electrophoretic Methods Electrochemical Methods. Polymerase Chain Reaction. 

The most common assay to determine mycotoxins is based on a quick solvent extraction (methanol-water, ethanol, chloroform, etc.) of the mycotoxin. The extract is then filtered and quantified via ELISA (enzyme-linked immunoassay) columns. The use of minicolumns is the most common because it is fast, repeatable, and reliable, and requires little expertise to run the assay. The test usually takes 5 minutes, so it allows processors to make important decisions about the acquisition and economic value of the grain. Other more time-consuming and complicated tests are thin-layer chromatography or other chromatographic techniques based on fluorescence or UV detectors. The main advantage of these tests is the identification of specific types of mycotoxins. 

Fiber-optic sensors based on controlled-release polymers provide sustained release of indicating reagents over long periods. This technique allows irreversible chemistries to be used in the design of sensors for continuous measurements. The sensor reported in this paper is based on a fluorescence energy transfer immunoassay. The sensor was cycled through different concentrations of antigen continuously for 30 hours. 

Forerunners of nonisotopic immunoassay had already appeared before radioimmunoassay was developed. For example, nephelometry is based on precipitation, which is known as the classical immune reaction, and the ideas of particle immunoassay and viroimmunoassay seem to have developed from the hemagglutination test. The principles of enzyme and fluorescence immunoassay had already been used as enzyme and fluorescence antibody techniques in histochemical analysis. In 1971, two groups reported use of an enzyme immunoassay (E5, V2). Leute et al. reported spin immunoassay, which has spurred recent development of nonisotopic immunoassays (L5). 

If the fluorescent emission spectrum of the bound labeled ligand is sufficiently displaced, enhanced or decreased in intensity (quenched) relative to that of the free labeled ligand, the resulting spectroscopic measurements can be used for quantitation without a separation step. Additionally, the techniques previously described in enzyme immunoassays, such as reactant-labeled immimoassay, can form the bases of fluorescent... 

The MIPs have also been utilized as the recognition elements in pseudoimmunoassays. " In this approach, MIPs are substituted for antibodies to quantify the amount of analyte in a biological sample, such as blood plasma. Most MIP immunoassays are competitive binding studies in which a radio- or fluorescent-labeled analyte is added to a mixture of the MIP and imlabeled analyte. After equilibrium is reached, some fraction of the labeled species is bound to the polymer surface and thus can be separated from the supernatant. The supernatant is then analyzed via scintillation or fluorescence techniques to determine the concentration of the original unlabeled analyte. Mosbach et al. have demonstrated that MIP-based immunoassays can rival the selectivity of antibody-based assays. Imprinted polymers for the opioid receptor ligands enkephalin and morphine were prepared and showed submicromolar (pM) level selectivity in a radioligand competition assay in aqueous buffers. The analysis... 

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