Nanostructured heated gold electrodes for DNA hybridization detection using enzyme labels

We report about two new types of nanostructured gold electrodes that can be heated electrically. At the directly heated gold micro-wire electrode, the microelectrode behavior is diminished upon galvanic deposition of gold nanostructures. The voltammetric waves observed with ferrocyanide turned into peaks. This suggests that it is the active electrode area rather than the mere geometric dimensions, what determines microelectrode behavior. Direct heating of this nanostructured gold wire electrode brought back the wave-like voltammogramms typical for microelectrodes. We also demonstrate with a second type of heated gold electrode, an indirectly heated sensor based on low temperature co-fired ceramics (LTCC), that DNA hybridization response of covalently attached enzyme labels is greatly improved by nanostructures. The voltammetric signal increase for the nanostructured electrode was 22-fold at 5°C and 6-fold at 70°C electrode temperature. We think that a trapping effect in the gold pores greatly increases sensitivity, in particular at lower electrode temperature.