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4 - Biosensors

Published online by Cambridge University Press:  23 October 2009

Kiyoshi Toko
Affiliation:
Kyushu University, Japan
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Summary

Principle of biosensors

A biosensor is a kind of a chemical sensor that measures chemical substances by means of biomaterials and related materials (see Table 1.3). Biosensors can be classified by the biomaterial used into enzyme, microbial, immuno-, organelle and tissue sensors (Fig. 4.1).

A biosensor is, in principle, made by immobilizing these biomaterials and related materials to a sensing membrane and combining this with an electrochemical device. As shown in Fig. 4.2, it converts the concentration of chemical substances to be measured into light, sound and oxygen concentration by means of the biomaterial-immobilized membrane. It is possible to estimate the concentration of chemical substances by changing this quantity to an electric signal using an electrode and a thermistor. In all, a biosensor system consists of a receptor membrane where the reaction (or response) takes place, a transducer that transforms the concentration of chemical substances into an electric signal and recording equipment or computer. In an SPR (surface plasmon resonance) biosensor, the change of refractive index near the membrane surface caused by an antigen–antibody reaction is quantified by the resonance-angle change, which can be simply transformed to an electric signal using an electronic circuit.

We use an electrode as a transducer in most cases. The method to obtain electric signals is classified roughly into potentiometry and amperometry.

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Publisher: Cambridge University Press
Print publication year: 2000

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  • Biosensors
  • Kiyoshi Toko, Kyushu University, Japan
  • Book: Biomimetic Sensor Technology
  • Online publication: 23 October 2009
  • Chapter DOI: https://doi.org/10.1017/CBO9780511541179.005
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  • Biosensors
  • Kiyoshi Toko, Kyushu University, Japan
  • Book: Biomimetic Sensor Technology
  • Online publication: 23 October 2009
  • Chapter DOI: https://doi.org/10.1017/CBO9780511541179.005
Available formats
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To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

  • Biosensors
  • Kiyoshi Toko, Kyushu University, Japan
  • Book: Biomimetic Sensor Technology
  • Online publication: 23 October 2009
  • Chapter DOI: https://doi.org/10.1017/CBO9780511541179.005
Available formats
×