Microchip-Based Electrochemical Enzyme Immunoassays

  • Madhu Prakash Chatrathi
  • Greg E. Collins
  • Joseph Wang
Part of the Methods in Molecular Biology™ book series (MIMB, volume 385)


In this chapter a microchip-based electrochemical enzyme immunoassay is developed and its performance is demonstrated for the determination of monoclonal mouse IgG as a model analyte. Such a direct homogeneous immunoassay requires the integration of electrokinetic mixing of alkaline phosphatase (ALP)-labeled anti-mouse IgG antibody (Ab-E) with the mouse IgG antigen (Ag) analyte in a precolumn reaction chamber, injection of immunochemical products into the separation channel, followed by rapid electrophoretic separation of enzyme-labeled free antibody and enzyme-labeled antibody-antigen complex. The separation is followed by a postcolumn reaction of enzyme tracer with p-aminophenyl phosphate (p-APP) substrate (S) and downstream amperometric detection of p-aminophenol (p-AP) product. Factors influencing the reaction, injection, separation, and detection processes are optimized. We have characterized the microchip-based immunoassay protocol. The resulting attractive analytical performance, along with distinct miniaturization and portability advantages of the electrochemical microsystem, offer considerable promise for designing self-contained and disposable chips for decentralized clinical diagnostics.

Key Words

Microchip microfluidic electrochemical detection immunossay antibody amperometry alkaline phosphatase 


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Copyright information

© Humana Press Inc., Totowa, NJ 2007

Authors and Affiliations

  • Madhu Prakash Chatrathi
    • 1
  • Greg E. Collins
    • 1
  • Joseph Wang
    • 2
  1. 1.Chemistry DivisionNaval Research LaboratoryWashington DC
  2. 2.Departments of Chemical and Materials Engineering and Chemistry and BiochemistryArizona State UniversityTempe

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