Monitoring antibody-antigen reactions at conducting polymer-based immunosensors using impedance spectroscopy

The mechanisms of antibody-antigen (Ab-Ag) interactions at conducting polypyrrole electrodes have been investigated using impedance spectroscopy techniques. The effects of the variation in ion exchange, solution composition, and the condition of the synthesis have been used to study the capacitive behavior of antibody-containing polypyrrole electrodes in the presence of the antigen. The theory of charge generation and transportation in the heterogeneous polymeric domains is proposed as the predominant basis for the analytical signals observed at these electrodes. The significant difference observed in the impedance response at different potentials confirmed that the Ab-Ag interaction was largely influenced by the applied potential. (C) 1999 Elsevier Science Ltd. All rights reserved.