Non-competitive immunoassay systems

FIGURE 54 A schematic of hie flow-through immunosensor equipped wifli (1) fluid inlet, (2) carbon current collector, (3) disposable immuno-column, (4) highly dispersed antibody-modified carbon particles (immunosorbent), (5) carbon counter electrode, (6) Ag AgCl reference electrode and (7) fluid outlet. (Reprinted from [16] wifli permission from Elsevier.) 

Electrochemical Sensors, Biosensors and Their Biomedical Applications 

There are also examples of non-competitive assays in the literature for analyzing different clinically important species. For example, an immnnosensor for the pathogenic bacterium Salmonella typhi and for bacterial toxins from pathogenic Vibrio chol-erae [21-23]. 

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Competitive immunoassay systems 5.3.2 Non-competitive immunoassay systems... 

In non-competitive immunoassays, the antigen is a sandwich between two antibodies, the capture antibody and the detection antibody. Typically, the capture antibody is coated to a solid phase, such as a tube or a well, and the detection antibodies are labeled with either an isotope or an enzyme. The amount of antigen in an unknown sample of these immunoassays is directly proportional to the amount of labeled detection antibody measured by the detection system. Examples of non-competitive assays are IRMA and ELISA. Figure 1 illustrates different types of binding. 

Enzyme immunoassay is widely used, both in competitive and non-competitive formats, for the bioanalysis of a broad range of low-molecular-weight compounds and macromolecules. Through the use of fluorogenic substrates and amplification systems such as avidin-biotin, the sensitivity of enzyme immunoassay has been developed to equal or exceed that of radioimmunoas-say.f ° The technique has found particularly wide applicability in the determination of new recombinant proteins, in demonstrating antibody responses to macromolecules, and in the measurement of biomarkers of disease, as well as in diagnostic medicine. 

Non-competitive solid-phase enzyme immunoassays based on the avidin-biotin system for the determination of antibody activity in sera ... 

An immunoassay is an analytical procedure that takes advantage of the very specific binding between antibodies and antigens to evaluate the characteristics of a system. Immunoassays can be classified as competitive or non-competitive. Competitive assays introduce a known amount of antibody-antigen complex to the sample and... 

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