Electrochemical impedance spectroscopy immunosensors

Yang P, Zheng QL, Xu H, Liu JS, Jin LT (2012) A highly sensitive electrochemical impedance spectroscopy immunosensor for determination of 1-pyrenebutyric acid based on the bifunctionality of Nafion/gold nanoparticles composite electrode. Chin J Chem 30 1155-1162... 

A label-free electrochemical impedance immunosensor for the rapid detection of E. coli 0157 H7 consists of immobilized anti- . coli antibodies on an indium-tin oxide IDA microelectrode [123]. The binding of E. coli cells to the IDA microelectrode surface increases the electron-transfer resistance, which is directly measured with electrochemical impedance spectroscopy in the presence of [Fe(CN)(6)] as a redox probe. The electron-transfer resistance correlates with the concentration of E. coli cells in a range from 4.36 X 10 to 4.36 X 10 cfu ml with a detection Umit of 10 cfu ml . ... 

Instrumental electroanalysis offers some alternatives for the detection of biological recognition events in immunosensors such as capacitive immunosensors and sensors based on electrochemical impedance spectroscopy. Both techniques are universal platforms for the detection of immunoreactions and hence bacteria, viruses, tumor markers, and more, as described above, have been detected with these methods. 

Navratilova I. and Skladal P., The immunosensors for measurement of 2,4-dichlorophenoxyacetic acid based on electrochemical impedance spectroscopy, Bioelectrochemistry, 62(1), 11-18, 2003. 

Bart, M., Stigter, E.C.A., Stapert, H.R., de Jong, G.J., van Bennekom, W.P. On the response of a label-free interferon-y immunosensor utilizing electrochemical impedance spectroscopy. Biosens. Bioelectron. 21, 49-59 (2005)... 

Xiao, R, Zhang, N Gu, H. etal. (2011) A monoclonal antibody-based immunosensor for detection of Sudan I using electrochemical impedance spectroscopy Talanta, 84, 204-211. 

Liu, X., Duckworth, PA. and Wong, D.K.Y. (2010) Square wave voltammetry versus electrochemical impedance spectroscopy as a rapid detection technique at electrochemical immunosensors. Biosens. Bioelectron., 25, 1467-1473. 

Yun et al. developed a label-free immunosensor based on aligned MWCNT arrays. Antibodies were attached to MWCNT ends, and binding of model antigen mouse IgG to the antibody-modified surface resulted in an increase in the electron-transfer resistance. Formation of the antibody-antigen complex was monitored by CV and electrochemical impedance spectroscopy (EIS), resulting in a DL of 200 ng mL with a dynamic range up to 100 pg mL for IgG. 

Katz E, WUlner 1 (2004) Immunosensors and DNA sensors based on impedance spectroscopy. In Springer series on chemical sensors and biosensors 2 (ultrathin electrochemical chemo- and biosensor). Springer, Berlin ffeidelberg New York, p 67... 

Impedance immunosensors measure changes in electrical field due to biorecognition phenomena. These changes could be overall electrical conductivity of the solution and capacitance alteration due to the Ab/Ag interaction on the electrode surface, which also can be reflected in impedimetric response. Electric impedance spectroscopy (EIS) is a sensitive technique that detects the electrical response of the system studied after application of a periodic small ampHtude AC signal. In recent years, the electrochemical impedance immunosensors have attracted extensive interest in the sensing formation of Ab/Ag (Darain et al., 2004 Chen et al., 2006 Gonzalez et al., 2007 Varki et al., 1999). 

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