Anodically electrodeposited iridium oxide films microelectrodes for neural microstimulation and recording

An efficient and reliable electrochemical method for preparing electrodeposited iridium oxide film (EIROF) microelectrodes by an anodic electrochemical process is reported. The EIROF microelectrodes exhibited remarkably high safe charge injection (Qinj) limits of ∼2.6 mC/cm2 for anodic-first pulses and ∼1.4 mC/cm2 for cathodic-first pulses, and the electrode impedance at 1 kHz was significantly reduced by ∼92%. The EIROF microelectrodes also exhibited good mechanical and electrochemical stability, as well as an excellent super-Nernstian slope in a broad pH range (1–13). All of these characteristics are greatly desired for neural sensor applications including electrical neural microstimulation, neural signal recording as well as pH monitoring in vivo. Moreover, the electrodepositing method can be facilely incorporated into thin-film technology and Microelectromechanical Systems (MEMS).