Recent developments in electrochemical immunoassays and immunosensors

Jeremy M. Fowler*, Danny K Y Wong, H. Brian Halsall, William R. Heineman

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

    51 Citations (Scopus)

    Abstract

    This chapter focuses on the various developments in electrochemical immunoassays and immunosensors after 2002. Electrochemical immunoassay is a solid phase system in which an antibody-antigen reaction takes place but the corresponding electrochemical detection is carried out elsewhere. However, an electrochemical immunosensor is a stand-alone device, with the immunoreaction and electrochemical detection occurring within the same device. There are several strategies for immobilizing a captured antibody on a solid phase, which include covalent attachment, physical adsorption, and electrostatic/physical entrapment in a polymer matrix. The (strept)avidin-biotin interaction technique is used to immobilize various types of biomolecules such as nucleic acids, polysaccharides, and proteins, including the capture antibody in immunoassay/immunosensor systems. Another commonly used affinity-based immobilization technique for capture antibodies in immunoassay systems involves a bacterial antibody-binding protein, the two most common of which are Protein A and Protein G. These proteins bind specifically to antibodies through their nonantigenic (Fc) regions, which allow the antigen binding sites of the immobilized antibody to be oriented away from the solid phase and be available to bind the target analyte. The application of conducting polymers such as polyaniline, polypyrrole, and polythiophene for immobilizing capture antibodies in immunoassay systems is widespread and they may be used in amperometric, potentiometric, and impedimetric immunoassay systems. Self-assembled monolayers (SAMs) are another attractive method for immobilizing the capture antibody in immunoassay systems, which takes advantage of the spontaneous chemisorption of alkanethiols to metals such as gold or silver to assemble highly ordered monolayers. Recently, interdigitated array (IDA) microelectrodes have gained popularity as an alternative transducer in electrochemical immunoassays in which a simple design of an IDA consists of a pair of interdigitated microelectrode fingers.

    Original languageEnglish
    Title of host publicationElectrochemical Sensors, Biosensors and their Biomedical Applications
    EditorsXueji Zhang, Huangxian Ju, Joseph Wang
    Place of PublicationAmsterdam, Boston
    PublisherAcademic Press
    Pages115-143
    Number of pages29
    Edition1st
    ISBN (Print)9780123737380, 0123737389
    DOIs
    Publication statusPublished - 2008

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