The fabrication and electrochemical characterization of carbon nanotube nanoelectrode arrays

We report a novel approach for the fabrication of nanoelectrode arrays using vertically aligned multi-walled carbon nanotubes (MWCNTs) embedded within a SiO2 matrix. Cyclic voltammetry and pulse voltammetry are employed to characterize the electrochemical properties of the MWCNT array. The unique graphitic structure of the novel MWCNT nanoelectrodes is compared with model systems such as highly oriented pyrolytic graphite and glassy carbon electrodes. Low-density MWCNT nanoelectrode arrays display independent nanoelectrode behavior showing diffusion-limited steady-state currents in cyclic voltammetry over a wide range of scan rates. Electroactive species can be detected at concentrations as low as a few nM. In addition, ultrasensitive DNA/RNA sensors are demonstrated using the low-density MWCNT arrays with selectively functionalized oligonucleotide probes. This platform can be widely used in analytical applications as well as fundamental electrochemical studies.