Comb interdigitated arrays (IDA) electrodes for more rapid and sensitive bead-based immunoassay

This research is dedicated to the development of electrode arrays suitable for a more sensitive and faster electrochemical immunoassay system Signal amplification is achieved through coupling the redox cycling of interdigitated array (IDA) electrodes with an enzyme label, /spl beta/-galactosidase. Comb IDAs enhanced the signal 3 times higher than coplanar IDAs. A magnetic bead-based enzyme assay, as a simulation of an immunoassay, has been performed using the comb and coplanar IDAs for detection. Comb IDAs enabled positioning the beads and attached enzyme closer to the sensing electrodes (/spl sim/10 gm). Detection time was less than 1 min. and the limit of detection was 70 amole of /spl beta/-galactosidase.