Electrochemical Capillary-driven Immunoassay and System

​Immunoassays are a widely used technology for applications ranging from clinical diagnostics to environmental monitoring. The basis of the immunoassay is the binding reaction between antigen and antibody, typically performed on a surface. Either the antigen or the antibody can be the target analyte. Subsequent to this reaction, the presence of the analyte is detected by one of several methods, including colorimetry, electrochemistry, fluorescence, and chemiluminescence. Among these methods, colorimetry (also called spectroscopic) and fluorescence are the most common. Immunoassays unfortunately rely heavily on laboratory instrumentation and thus do not work well at the point-of-care or point-of-need. A related technology, the lateral flow assay (LFA) simplifies the work flow but lacks the sensitivity and specificity of the traditional immunoassay.

Electrochemical detection is not widely used with immunoassays due to challenges associated with coupling antibodies to the electrodes. However, electrochemistry is widely used for other clinical diagnostics with the handheld glucometer as the major example of this application field.