Presence-sensing devices components

Redox enzymes are the active component in many electrochemical enzyme electrode biosensor devices.1821 The integration of two different redox enzymes with an electrode support, in which one of the biocatalysts is photoswitchable between ON and OFF states, can establish a composite multisensor array. The biomaterial interface that includes the photoswitchable enzyme in the OFF state electrochemi-cally transduces the sensing event of the substrate corresponding to the nonphoto-switchable enzyme. Photochemical activation of the light-active enzyme leads to the full electrochemical response, corresponding to the analysis of the substrates of the two enzymes. As a result, the processing of the signals transduced by the composite biomaterial interface in the presence of the two substrates permits the assay of the... 

Biosensors and devices may also include fiber components. Biosensors essentially contain two main components. These are the sensing element, which senses the molecule of interest, and the transducer, which generates a signal. Amyloid fibrils and other protein nanofibers could be used in biosensors in two ways. The first is as a scaffold to immobilize the sensing element on a nanoscale as described above. The second use is as a coating on the transducer where the presence of the protein fiber could enhance device performance. This enhancement could be carried out either with or without the aid of a further conductive coating (see Section 4.1 above). 

The detector is a device that senses the presence of a solute in the eluent from a chromatographic column and, thus, the output, suitably presented (for example, on a chart recorder) can display the nature of the separation and permit a quantitative assessment of the sample components. Excluding the column, the detector is the most important component of the liquid chromatograph as its design determines the accuracy and precision of the LC analysis. Many detectors have been developed based on a variety of different sensing principles, but only 12 are... 

Proximity Sensor An electromagnetic device that senses the presence or absence of a component through its effect on a magnetic field in the sensing unit. 

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