High charge storage capacity electrodeposited iridium oxide film on liquid crystal polymer-based neural electrodes

This research presents the development of neural electrodes with a high charge storage capacity using electrodeposited iridium oxide ilm (EIROF). The neural electrode was fabricated on a lexible liquid crystal polymer (LCP) substrate, which has a low moisture absorption rate and a low moisture permeability. On the electrode sites, iridium oxide was electrodeposited to increase the charge storage capacity for facilitating both neural stimulation and neural recording. Although EIROFs have been previously proposed as an electrode material, the fabrication process was not thoroughly investigated and optimized.⁽²⁰⁾ After electrodeposition using different numbers of rectangular voltage pulses and triangular waveforms, the iridium oxide electrodes were characterized in terms of charge storage capacity and electrochemical impedance. The surfaces of EIROFs were examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In addition, the elementary composition of the EIROF surfaces was quantitatively determined using X-ray photoelectron spectroscopy (XPS). The in vivo neural recording from the rat ventral poster lateral (VPL) nucleus successfully showed that the proposed electrode is feasible for recording the neural activity.