PEDOT:PSS as a transparent electrically conducting polymer for brain stimulation electrodes

The aim of this work is to test and evaluate Poly -(3,4-ethylenedioxythiophene) - poly (styrenesulfonate), simply known by the abbreviation PEDOT:PSS as a possible low cost and transparent electrically conducting polymer for the fabrication of magnetic resonance imaging (MRI) compatible brain stimulation electrodes. During the preliminary testing, the fabricated PEDOT:PSS structures with Polyimide as base layer created no artefacts under MR as well as X-Ray imaging. Additionally, as the thickness of the tested PEDOT:PSS structure was increased from 390nm to approximately 5.80μm by depositing additional material layers, the measured average electrical resistance decreased from 184KΩ to 25.37KΩ.The conventional metal-based electrodes hinder the use of MR or optical imaging during electrophysiological neuroscientific investigations of the brain. Therefore, a hybrid brain stimulation cum recording electrode array fabricated using polyimide as base material and PEDOT:PSS as the transparent electrically conducting material opens the possibility of electrically stimulating brain while simultaneously reaping the benefits of the MR imaging or the optical imaging (e.g. calcium imaging, two-photon microscopy, etc.).