Long neuroprobes based on silicon dicing and iridium oxide for electrical stimulation/recording

This paper synthesizes the development of a new 3D neuroprobe array, constituted by microelectrodes capable of electrical stimulation and recording. The array´s design relies on a bulk silicon substrate dicing technology and it comprises 6 × 6 neuroprobes with three different penetrating lengths (from 3 to 4 mm) and a 180 μm cross-section. A reproducible fabrication method was demonstrated, capable of producing longer shafts than in previously reported arrays. In addition, sputtered titanium/iridium oxide microelectrodes have shown the required performance, with a consistent reversible electrochemical behavior and an impedance value of 145 Ω in the same frequency range as the stimulation protocols.