A MIXED SELF-ASSEMBLED MONOLAYER FOR AN IMPEDIMETRIC IMMUNOSENSOR

A synthetic peptide with the amino acid sequence 135-154 of the capsid protein VP1 of the foot-and-mouth-disease virus was modified with ome ga-hydroxyundecanethiol and applied together with non-derivatised omeg a-hydroxyundecanethiol for consecutive adsorption onto gold electrodes according to self-assembling procedures. The binding of a specific an tibody to prepared recognition layers could be monitored by measuremen t of impedance or capacitance. In order to avoid non-specific effects, all measurements were performed in the presence of BSA. The complex b etween the antigenic peptide and the antibody was split by applying 6 M urea solution. The gold electrodes were mounted into an optimised fl ow-through system in order to perform capacitance-time measurements. T he immobilised peptide can be recognised repeatedly by specific antibo dies. (C) 1996 Elsevier Science Limited