Large-area interdigitated array microelectrodes for electrochemical sensing

Advanced photolithography developed for the semiconductor industry has been used to fabricate interdigitated microelectrode arrays that pass steady-state limiting currents of up to 230 nA/μM analyte — 2.5 times more than the most sensitive interdigitated array built to date, and exhibit response times of ∼5 ms. This performance results from the small interelectrode gap and the large active area of the device (4 mm2), a combination enabled by advanced photolithography. We describe the fabrication of these arrays and the characterization of their performance in two environments: an aqueous solution of Ru(NH3)63+ and a dinitrotoluene solution in acetonitrile. The scaling of array performance parameters with device dimensions is also presented.