Physics And Chemistry Basis Of Biotechnology - De Cuyper - tiera.ru

Sheila J. Sadeghi et al
a transducer which converts the signal generated by the selector into a signal
fit for amplification,
a detector, an electronic component designed to give a quantitative signal as
depicted in Figure 3.
The coupling step between selector and transducer is usually the bottleneck in the
engineering of a biosensor; in electrochemical sensors this step is represented by the
electrical contact between the redox protein and the electrode surface.
Figure 3. Schematic representation of a biosensor.
More than half of all sensors appearing in the literature can be classified as
electrochemical sensors. These can be subdivided into either amperometric,
potentiometric or conductometric sensors. In the amperometric category, an enzyme is
typically coupled to an amperometric electrode and as the enzyme reacts with the
substrate, a current is produced that is correlated to the analyte concentration. In this
case, the bottleneck is the coupling between the enzyme and the electrode so that
efficient conduction of the electrons is achieved. The second classification,
potentiometric sensors, can be sub-divided into one group that utilises an immobilised
enzyme on the surface of a glass pH electrode and a second type based on the
production or consumption of protons by the enzyme as measured by the electrode.
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