Chemical Sensors Based on Microorganisms, Living Cells and Tissues
23.1 Living Material Biosensors: General Principles
Biocatalytic sensors were initially developed using enzymes that have been isolated from biological media or organisms and that catalyze the conversion of a substrate. Signal transduction in enzymatic sensors can be achieved by monitoring the concentration of a reactant or product that is involved in the enzymatic reaction.
Instead of using enzymes that have been isolated it is possible to use microorganisms, living cells or living tissues that contain analyte-specific enzymes. By metabolic processes, the analyte undergoes conversion to particular products, this process involving consumption of oxygen or another reactant. Monitoring of reactant consumption or product formation provides a means of signal transduction in metabolism-based biosensors.
Comprehensive overviews of living material-based biosensors are available in several recent books [1–3] and reviews [4–7]. Mathematical modeling of whole-cell biosensors is discussed in ref. .
Due to the similarity of the functioning principles, the design of metabolism-based sensors is essentially similar to that of enzymatic sensors. Thus, a layer containing the selected living material is integrated with a transducer device that indicates the concentration of a reactant or product involved in the metabolism of the sensing entity. In this way, the isolation of the relevant enzyme is avoided and the enzyme ...