Immunoassay system

Most immunoassay kits and many commercial immunoassay analyzers are based on heterogenous EIA or FIA. These include an immunoassay system that uses FIA linked to radial partition chromatography of the antibody—antigen complex (39) a system that uses antibody-coated tubes for enzyme immunoassay of a variety of hormones and dmgs (40) and a system that uses either a sandwich or competitive FIA format to measure a variety of analytes (41). 

Figure 22.18 Biotinylated liposomes may be used in immunoassay systems to enhance the signal for detection or measurement of specific analytes. The liposome components may be constructed to include fluorescent molecules to facilitate detection of antigens within tissue sections.

The following sections briefly describe the principal enzymes used for conjugation with other protein molecules, particularly in the design of ELISA and other immunoassay systems. 

The application of conducting polymers such as polyaniline, polypyrrole, and polythiophene for immobilizing capture antibodies in immunoassay systems is widespread. 

T.K. Lim, H. Ohta, and T. Matsunaga, Microfabricated on-chip-type electrochemical flow immunoassay system for the detection of histamine released in whole blood samples. Anal. Chem. 75, 3316-3321 (2003). 

Antibody molecules have no inherent characteristic that facilitates their direct detection in immunoassays. A second important step in developing a successful immunoassay, therefore, involves the incorporation of a suitable marker . The marker serves to facilitate the rapid detection and quantification of antibody-antigen binding. Earlier immunoassay systems used radioactive labels as a marker (radioimmunoassay RIA) although immunoassay systems using enzymes (enzyme immunoassays EIA) subsequently have come to the fore. Yet additional immunoassay systems use alternative markers including fluorescent or chemiluminescent tags. 

Immunoassays have found widespread application in detecting and quantifying product impurities. These assays are extremely specific and very sensitive, often detecting target antigen down to parts per million levels. Many immunoassays are available commercially, and companies exist that will rapidly develop tailor-made immunoassay systems for biopharmaceutical analysis. 

McConnell RJ, Fitzgerald SP, Lamont JV (1992) Trenbolone and 19-nortestosterone residue analysis by immunoaffinity chromatography and high-performance liquid chromatography and/or an enzyme-linked immunosorbent assay. In Morgan MRA, Smith CJ, Williams PA (eds) Food safety and quality assurance applications of immunoassay systems. Elsevier, Barking, p 245... 

Chemiluminescent immunoassay systems, commercial, 14 151 Chemineer CD6 agitator, 1 739 Chemineer CD6 impeller, 16 673, 701, 703 Chemisorbed water, 23 71 Chemisorption, 1 583-584 for indoor air cleaning, 1 834 parameters of physical adsorption and chemisorption contrasted, l 583t Chemisorption chromatography, 6 405 Chemistry. See also Combinatorial... 

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