We studied nanoscale interdigitated array electrodes (nano-IDAEs) to create a detector platform for highly sensitive biosensing devices. We successfully fabricated a gold nano-IDAE with 1000 pairs of electrodes (width and gap both 250 nm) and a 1 mm band length. We also fabricated a series of IDAEs whose widths and gaps ranged from 250 nm to 2 mu m, and performed cyclic voltammetry with the IDAEs using 100 mu m of ferrocenylmethyl trimethyl ammonium bromide solution to evaluate their characteristics. As the width and gap (line and space) of the IDAEs decreased, the difference between the experimental and theoretical limiting currents became larger, and when the line and space were 250 nm, the limiting currents were 20% higher than the theoretical value. We also employed the nano-IDAEs for measuring adrenaline. We demonstrated that the collection efficiency of 0% obtained when using a 2 mu m IDAE could be improved to more than 60% when using a 250 nm IDAE. (C) 2008 The Electrochemical Society.