An Array of Silicon Dual Microneedle Electrodes Integrated With mini-LEDs for Electrophysiological Recording And Simultaneous Application of Electrical and Optical Stimuli to the Retina for Artificial Vision

We report a novel hybrid neural interface device that not only enables simultaneous application of electrical and optical stimuli but also offers electrophysiological recording capability. A 6×6 silicon dual microneedle electrode array was fabricated and each pair consisted of recording and stimulating electrodes. A mini-LED matrix was also integrated underneath the electrode array to deliver optical stimulation. Spiking activities of retinal ganglion cells of an ex-vivo retina were successfully recorded in response to electrical and optical stimuli applied from the fabricated device.