Simultaneous Determination of Several Analytes Using Immunochemical Techniques - An Overview
Ursula Bilitewski
Gesellschaft für Biotechnologische Forschung mbH, Mascheroder Weg 1, 38124 Braunschweig, Germany
Article history:
Received October 27, 1997
Accepted April 7, 1998
Key words:
combination of several labels, spatial separation of affinity reactions, enzyme immunoassays, fluorescent immunoassays, immunosensors
Summary:
Immitnoanalysis is based on the recognition of analytes by antibodies with the determination being done either through suitable labelled compounds or directly using affinity sensor systems. Different analytes can only be distinguished by different antibodies requiring the development of multi-channel assays or sensors, which allow monitoring of the interactions of each single antibody. An obvious approach was the incubation of the sample with a mixture of all relevant antibodies together with the corresponding tracers. For each analyle another label had to be used to allow the independent analysis of the different affinity reactions. This approach was, however, limited by the number of tracers which could be distinguished within one assay under identical conditions. Alternatively, the different affinity reactions were spatially separated during the analytical procedure, which led to the applicability of only one label for all analytes. The determination of the different analytes was achieved by a corresponding spatially resolved signal transduction. As a consequence, the number of analytes, which could be determined simultaneously, was limited by the degree of spatial resolution which could be achieved by the coupling procedure, the tolerable complexity of the resulting system and the degree of spatial resolution achievable by the signal transduction device.
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