Honeycomb-type retinal device using chemically derived iridium oxide biointerfaces

Long-term operational stability and high-efficiency neuron stimulation are key to the development of retinal prostheses. In this research, a retinal device with a chemically inert and flexible substrate is introduced, which satisfies these requirements. We have developed a honeycomb-type retinal device that has a high-performance electrode for suprachoroidal transretinal stimulation. The device structure, in which conjunctional bioceramic substrates are embedded with large numbers of stimulating electrodes, provides high-resolution electrical stimulation. The custom CMOS microchip precisely controls the stimulation delivery of the electrodes to initiate artificial vision, offering a partial remedy for retinal ophthalmic diseases. The CMOS chip design was optimized to drastically reduce the number of input wirings. A high-performance stimulating electrode based on iridium oxide was fabricated using a unique solution process called chemical bath deposition (CBD). The honeycomb-type retinal device, equipped with CBD-derived iridium oxide electrodes, was used to evaluate the electrodes’ and device’s performances in vitro.