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Graphite-Composites Alternatives for Electrochemical Biosensor

E. Alhadeff,N. Bojorge

Published 2011 in Unknown venue

ABSTRACT

The basic principle of detection of a biosensor is based on the specific interaction between the analyte of interest and the recognition element. As a result of this specific interaction, changes are produced one or several physical-chemical properties (pH, electron transference, heat transfer, change of potential or mass, variation of optical properties, etc.). These changes are detected and can be measured by a specific transductor (Thevenot et al., 2001; Wang, 2004). Electrochemical biosensors are based on the electrochemical species consumed and /or generated during a biochemical interaction process of a biological active substance and analyte. Electrochemical biosensors, especially the amperometrics, have an important position among the biosensors. Since 2000s until the completion of this review, intensive research activity has been devoted to the development of amperometric biosensors. The statistic in ScienceDirect search showed 6950 items found for publication made with pub-date > 1999 and keywords Electrochemical biosensor. Of which about 38% with application to detect ethanol, 47 % for glucose and 15% to phenolic compound. The electrochemical biosensor usually consists of three phases: receptors phase, transducer phase and a signal amplifier phase. The receptor phase incorporates a biological or biomimetic recognition element (nucleic acid, enzyme, anti-body, tissue, organelles or whole cells). The most important phase in an amperometry biosensor is the receptor biomolecule by the selectivity of the device to a given analyte or condition. The transducer is the conductive phase, which converts a biochemical signal into a reading or measurement. And the amplifier is the computerized apparatus/software using to boosts/readout of signal. The role of the transducer in a biosensor is to generate a measurable signal of the analyte interacts with the biological molecule associated with the transducer surface. So, in the case of the optical transducer, it generates a signal measured as a light intensity proportional to the concentration of analyte in the sample; this may be an inverse relationship. The composite-films of the surface optical biosensor has an important role in the process in which changes in optical characteristics such as absorption, rotation, refractive index, bio/chemiluminescence, and fluorescence are related to the analyte concentration (Koncki et al., 2001). Martin (2002) showed how the fiber optical immunosensors based on long-period gratings that have limited sensitivity at the refractive index of ordinary aqueous solutions (~1.33). And using composite such as films of titanium dioxide, for example, can raise the local refractive index of the sensor (~1.42), thus increasing sensitivity. Titanium dioxide is

PUBLICATION RECORD

  • Publication year

    2011

  • Venue

    Unknown venue

  • Publication date

    2011-07-20

  • Fields of study

    Materials Science

  • Identifiers
    DOI 10.5772/17957
  • External record

    Open on Semantic Scholar

  • Source metadata

    Semantic Scholar

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