Secondary chemical signals, enzyme reaction

The majority of the biosensors that have been reported are based on the deposition of biologically active species such as enzymes and antibodies at the surface of an electrochemical or optical transducer. The most common principle is to identify the analyte by use of a chemically selective enzyme. The enzyme-substrate reaction produces a secondary chemical signal by means of catalysis, e.g. H" or H2O2. This signal is then recognized and quantitatively converted to an electrical signal, e.g. a potential, a current, or a change of absorption or fluorescence, by a suitable transducer. 

IlEible 14-2. Examples for enzyme reactions producing secondary chemical signals and corresponding transducers. Trivial names of the enzymes and systematic numbers (EC-numbers) are given. 

Among the very few examples for chemical signal amplification after analyte binding to the MIP site, a secondary reaction in a competitive ELISA-analogous assay had been established with a glued MIP particle film [4], Furthermore, with an about 100 nm thin protein-imprinted functional polyaniline film, the enzyme activity of bound peroxidase was used to retrieve quantitative data about MIP site capacities [62]. 

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