Antigen amperometry

In amperometry, the current produced by the oxidation or reduction of an electroactive analyte species at an electrode surface is monitored under controlled potential conditions. The magnitude of the current is then related to the quantity of analyte present. However, as both antibody and antigen are not intrinsically electroactive, a suitable label must be introduced to the immunocomplex to promote an electrochemical reaction at the immunosensors. In this respect, enzyme labels including the... 

Immunoassays, electrochemical — A quantitative or qualitative assay based on the highly selective antibody-antigen binding and electrochemical detection. Poten-tiometric, capacitive, and voltammetric methods are used to detect the immunoreaction, either directly without a label or indirectly with a label compound. The majority of electrochemical immunoassays are based on -> voltammetry (-> amperometry) and detection of redox-active or enzyme labels of one of the immunochemical reaction partners. The assay formats are competitive and noncompetitive (see also -> ELISA). 

Since antibody-antigen binding does not produce a detectable signal by itself, several techniques involve a tag such as an enzyme, radioisotope, or fluoroph-ore to monitor the reaction with a variety of optical and electrochemical detectors. One group of detectors generally uses fluorescence and chemiluminescence while another employs amperometry and potentiometry. Electrochemical immunoassays are emergent alternatives to existing immunochemical... 

Lithographic gold electrodes were modified in two ways (1) formation of a SAM of the bipodal alkanethiol DT2 followed by covalent linking of whole anti F. tularensis antibody and (2) direct chemisorption of F. tularensis antibody fragments Francisella tularensis Step and sweep amperometry 4.5 ng/mL for the lipopolysac-charide antigen isolated from F. tularensis and 31 bacteria/ mL for the F. tularensis bacteria/- Dulay et al. (2014)... 

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