A new flexible microfabricated polyimide-based platinum electrodes for stimulation of rat retinal tissue in vitro and recording using a multi-electrode array

We present a new flexible micro-fabricated polyimide-based platinum (Pt) array of four planar electrodes system for local stimulation of the rat retinal photoreceptor layer and simultaneous extracellular recording (ECR) from large population of retinal ganglion cells (RGCs) using the MEA60 setup (Multi Channel Systems) in vitro conditions. Our results revealed that RGCs present On or/and Off light-driven responses on a majority of recorded sites. Local electrical stimulation induced excitatory responses in a small number of RGCs hypothesised to the poor electrode- tissue interfacial contact. Two approaches are proposed to enhance the electrode- tissue interfacial contact to improve the efficiency of stimulation.