Electrochemical modulation of antigen-antibody binding.

The label-free amperometric detection of a rabbit IgG antigen by an anti-rabbit IgG antibody is achieved by observing the electrochemistry at a glassy carbon electrode modified with antibody entrapped in an electrodeposited polypyrrole membrane. In a flow injection apparatus the electrode is pulsed between -0.2 and +0.4 V versus Ag/AgCl. The pulsing of the electrode switches the polypyrrole membrane between the oxidised and reduced states. When antigen is injected into the flow stream a change in current is observed at the electrode despite the antigen or antibody being redox inactive at the potentials employed. It is proposed that this current is due to a change in the flux of ions into and out of the polypyrrole matrix during a pulse when the poly-anionic antigen is present. The immunoreaction was reversible because the 200 ms pulse at each potential was too short to allow secondary bonding forces (hydrogen bonding and hydrophobic forces) which are responsible for the strength of the antibody-antigen complex to be established. The consequence of the reversibility of the antigen-antibody binding is a low apparent affinity constant but an easily regenerated recognition interface.

[1]  J. Justin Gooding,et al.  The application of alkanethiol self-assembled monolayers to enzyme electrodes , 1999 .

[2]  Omowunmi A. Sadik,et al.  Bioaffinity Sensors Based on Conducting Polymers: A Short Review , 1999 .

[3]  D. B. Hibbert,et al.  Electrodeposited polytyramine as an immobilisation matrix for enzyme biosensors. , 1998, Biosensors & bioelectronics.

[4]  M. Heller,et al.  Active microelectronic chip devices which utilize controlled electrophoretic fields for multiplex DNA hybridization and other genomic applications , 2000, Electrophoresis.

[5]  D. B. Hibbert,et al.  Immobilisation of enzyme throughout a polytyramine matrix: a versatile procedure for fabricating biosensors , 1999 .

[6]  Anita Sargent,et al.  The electrochemistry of antibody-modified conducting polymer electrodes , 1999 .

[7]  Z. Liron,et al.  Voltage-induced inhibition of antigen-antibody binding at conducting optical waveguides. , 2002, Biosensors & bioelectronics.

[8]  E. Harlow,et al.  Using Antibodies: A Laboratory Manual , 1999 .

[9]  Anita Sargent,et al.  Monitoring antibody–antigen reactions at conducting polymer-based immunosensors using impedance spectroscopy , 1999 .

[10]  G. Wallace,et al.  Pulsed amperometric detection of thaumatin using antibody-containing poly(pyrrole) electrodes , 1994 .

[11]  G. Wallace,et al.  Development of a polypyrrole-based human serum albumin sensor , 1991 .

[12]  G. Wallace,et al.  Characterisation and analytical use of a polypyrrole electrode containing anti-human serum albumin , 1998 .

[13]  M. Heller,et al.  Electric field directed nucleic acid hybridization on microchips. , 1997, Nucleic acids research.

[14]  E. Work,et al.  Laboratory techniques in biochemistry and molecular biology , 1969 .

[15]  Joseph Wang,et al.  New label-free DNA recognition based on doping nucleic-acid probes within conducting polymer films , 1999 .

[16]  G. Wallace,et al.  Determination of P-Cresol (and Other Phenolics) Using a Conducting Polymer Based Electro-Immunological Sensing System , 1994 .

[17]  D. B. Hibbert,et al.  Parameters important in tuning the response of monolayer enzyme electrodes fabricated using self-assembled monolayers of alkanethiols. , 2000, Biosensors & bioelectronics.

[18]  M. Heller,et al.  Electric manipulation of bioparticles and macromolecules on microfabricated electrodes. , 2001, Analytical chemistry.

[19]  O. Sadik,et al.  Pulsed electrochemical technique for monitoring antibody-antigen reactions at interfaces , 1998 .

[20]  A. Asanov,et al.  Regenerable biosensor platform: a total internal reflection fluorescence cell with electrochemical control. , 1998, Analytical chemistry.

[21]  Gordon G. Wallace,et al.  Pulse damperometric detection of proteins using antibody containing conducting polymers , 1993 .