Vertically oriented single-wall carbon nanotube/enzyme on silicon as biosensor electrode

Thin films of vertically aligned individual single-wall carbon nanotubes (SWNTs) were deposited on silicon using a chemical vapor deposition (CVD) process. Oriented SWNT growth was achieved by employing two methods of catalyst precursor self-assembly followed by ethanol CVD. Using the silicon substrate as the working electrode in an electrochemical cell and the enzyme β-NAD (nicotinamide adenine dinucleotide) synthetase dissolved in a buffered electrolyte solution, the enzyme was attached at the nanotube ends. This was shown using scanning electron microscopy and cyclic voltammetry. Enzyme immobilization on the 1 nm to 2 nm diameter tube ends of the individual SWNTs will allow for dense packing of the enzyme and utilization of the electrode as an enzymatic sensor in a biofuel cell configuration.