Biocompatibility of polyimide microelectrode array for retinal stimulation

Artificial retina is aimed for the stimulation of remained retinal neurons in the patient with degenerated photoreceptors. Microelectrode arrays have been developed for this as a part of stimulator. To minimize the damage during ophthalmic surgery and to get better contact to retina, flexible polyimide, which can be fabricated based on semiconductor manufacturing, was selected as the substrate material. In vitro biocompatibility of polyimide microelectrode array (MEA) was tested by co-culture with human retinal pigment epithelial cells (RPE). In vivo biocompatibility was tested in the rabbit eyes. The polyimide MEA showed good affinity to human RPE and did no harmful effect. It also showed very good stability and safety in rabbit eyes by 12 weeks.