ELECTRON-TRANSFER THROUGH AN IMMUNOGLOBULIN LAYER VIA AN IMMOBILIZED REDOX MEDIATOR

As a step towards a voltammetric immunoassay with antibodies directly attached onto the electrode surface, the mediated oxidation of a redox active label has been investigated with a model system. Butyl ferroce ne served as a model for the mediator and was coimmobilized onto a gla ssy carbon electrode within a layer of bovine immunoglobulin G, which mimiked the antibody. An overlaid polyvinyl ferrocene layer was employ ed to simulate a ferrocene-tagged high molecular weight antigen bound to the immobilized antibodies. A mediated electron transfer could only be demonstrated with butyl ferrocene as mediator, whereas other compo unds failed to support an electron transfer between the polyvinyl ferr ocene layer and the electrode through the layer of immunoglobulin.