High-Frequency Stimulation of Normal and Blind Mouse Retinas Using TiO2 Nanotubes, Adv. Funct. Mater. 2018, 28:1804639.

With three models in commercial use, artificial retinas are the most concrete hope to restore sight to blind patients, notably those affected with retinitis pigmentosa. However, present architectures are costly to produce, while the restored visual acuity remains below the legal threshold for blindness. Furthermore, the complexity of current systems with tethered application‐specific integrated circuits (asics) requires complex surgeries, with risks of complications and failures. In the search for new nanomaterials, it is demonstrated that, when placed in contact with photoreceptors (control mouse retinas) or directly with bipolar cells (rhodopsinP23H mouse retinas, a model of retinitis pigmentosa), films of vertically aligned anatase titanium dioxide (TiO2) nanotubes can drive the activity of the retinal network for stimulation frequencies up to the video rate (25 Hz), in response to short (5–20 ms), small (50–100 µm) light spots. Acting as continuous arrays of electrodes, these films should allow a fine tuning of prosthetic stimulations, through modulation of the spot size, duration, and precise localization over the implant surface.