Tellurium nanowire retinal nanoprosthesis improves vision in models of blindness.

Present vision restoration technologies have substantial constraints that limit their application in the clinical setting. In this work, we fabricated a subretinal nanoprosthesis using tellurium nanowire networks (TeNWNs) that converts light of both the visible and near-infrared–II spectra into electrical signals. The broad-spectrum coverage is made possible by a combination of narrow bandgaps, strong absorption, and engineered asymmetries. Implanted into blind mice, the TeNWNs restored pupillary reflexes and enabled visually cued learning under visible and near-infrared 1550-nanometer light. In nonhuman primates, TeNWNs elicited robust retina-derived neural responses, confirming biocompatibility and feasibility. By restoring lost photosensitivity and extending vision to near-infrared, this nanoprosthesis offers a promising approach for restoring vision. Editor's summary: Prosthetic retinal implants hold promise for improving vision in blind and visually impaired individuals. Wang et al. developed a neuroprosthesis using tellurium nanowires (TeNWNs) that allowed efficient photovoltaic conversion in both the visible and the infrared range (see the Perspective by Fernández). TeNWNs showed good biocompatibility and did not require external power sources. The neuroprosthesis was able to improve vision in mouse and nonhuman primate models. The use of TeNWNs could substantially improve the efficacy of retinal neuroprostheses in restoring vision in blind and visually impaired individuals. —Mattia Maroso INTRODUCTION: In nature, there are animals, such as snakes, that assess their environment more accurately by sensing both infrared radiation and the visible-light spectrum. The human eye lacks photoreceptors responsive to the infrared spectrum, and infrared light with a longer wavelength and lower energy cannot trigger visual signals. In patients with severe eye diseases (e.g., macular degeneration), infrared vision could, in principle, aid vision in low light and darkness. Developing technologies that use a wider spectrum of light, including infrared, could provide notable benefits. RATIONALE: Present designs for broad-spectrum retinal protheses use nanoparticles or photodiodes to convert infrared into visible light or heat to stimulate retinal cells. Because they require injections or bulky auxiliary devices, there are safety and practicality issues for potential application to humans. Creation of a safe, easy-to-implant retinal prosthesis that enables the processing of both visible and infrared light may restore vision loss and enhance natural vision. We designed a next-generation retinal nanoprosthesis based on tellurium nanowire networks that intrinsically converts broadband light—including visible to infrared light—with efficient photovoltaic conversion, yielding giant with photocurrents under zero-electric bias and without the need for extra auxiliary equipment. We then achieved safe and simple implantation in the subretinal space of mice and Macaca fascicularis. RESULTS: Through theoretical calculations, we show spontaneous giant and wide-spectrum photocurrents of tellurium nanowire networks to be correlated with the asymmetry of nanowire lattice internal defects and external interfacial effects. Through a combination of narrow bandgaps, strong absorption, and engineered asymmetries, tellurium optoelectronic nanodevices showed record-high photocurrents and the widest spectrum of responsive photosensitivity wavelengths compared with reported techniques for the restoration of photosensitivity in blindness, covering the visible to near-infrared–II range. Preimplantation tests confirmed the stability of the nanoprosthesis's optoelectronic properties and its precise response to light patterns. In blind mice, the implanted nanoprosthesis replaced damaged photoreceptors and triggered responses in both the optic nerve and visual cortex. Implanted mice showed better light-induced pupil reactions and improvement in light-associated learning behaviors (such as water reward–based visual-cue associative learning and choice-box tasks) when compared with untreated mice and when using light intensities nearly 80 times weaker than the clinical safety threshold. The biocompatibility and efficacy of the proposed nanoprosthesis was further demonstrated in nonhuman primates (Macaca fascicularis), where the nanoprosthesis was tightly bound to the retina in the subretinal space and generated robust retina-derived responses to visible and infrared light. CONCLUSION: Our study provides biologically feasible parameters for a retinal prosthesis using designed tellurium nanowire networks. These nanowires naturally convert light into photocurrent signals with zero electrical bias and can cover the visible to infrared spectrum. The tested nanoprosthesis generates strong photocurrents to activate the remaining retinal circuitry in a dysfunctional eye, works through a simple subretinal implantation procedure, and avoids bulky intra- and extraocular components. In blind mice, this retinal nanoprosthesis restored the brain's response to light and improved vision-based behaviors at clinically safe light levels. Nonhuman primates implanted with this nanoprosthesis gained infrared vision without impairment of normal vision. This successful animal study paves the way for future human trials, showcasing the potential of this prosthesis to restore visible vision and expand augmented infrared perception for blind humans and offer a safer, more effective, and wider-spectrum solution than existing technologies. A next-generation nanoprosthesis that restores and enhances vision.: Tellurium possess broad-spectrum optical absorption from visible to infrared light (top left). A subretinal-implanted tellurium nanoprosthesis replaces degenerated photoreceptors and generates photocurrents to activate residual retinal circuitry (bottom left) and the occipital cortex (top right). Giant, spontaneous, bias-free photocurrents and minimally invasive easy implantation is achieved by asymmetry engineering and nanowire network morphology (bottom right). Together, these properties make tellurium nanowire networks (TeNWNs) the next generation of visual prosthesis technology. [ABSTRACT FROM AUTHOR]