Towards amperometric immunosensor devices

In contrast to optical immunosensors, the electrochemical detection of an immunanalytical reaction does require a labeling, but allows an easier discrimination of specific and non-specific binding. We present a concept and first results for a multivalent amperometric immunosensor system which is based on silicon technology. The capture molecule streptavidin, covalently immobilized on silica, allows the immobilization of biotinylated antigens at a defined density. A nanostructured gold electrode serving as a stable network of nanowires is expected to be beneficial for the electrochemical detection of bound ferrocene-labeled antibody molecules. The results presented focus on site-specific immobilization of streptavidin on silica and reduction of non-specific binding of proteins. (C) 1997 Elsevier Science Limited.