Scientists have developed a novel retinal implant that not only restores the vision of blind mice, but also allows them to see infrared light – even healthy eyes cannot detect it.
Made of interwoven dental nanowires, the device represents an important step in artificial vision technology that can ultimately help millions of people around the world blind.
The study, published today in science, shows how nanoprostheses can successfully restore the reflection and visual behavior of genetically blind mice while extending their perception into the near-infrared spectrum. In non-human primate tests, the implant was proven to be safe and effective, with a macaque with vision gaining infrared sensitivity without losing normal vision.
Go beyond traditional methods
Current vision recovery technologies face significant obstacles, including electrical interference, short-term effectiveness, and the need for bulky external devices. Most retinal prostheses require external power, camera and control modules to limit real-world applications.
The new Tellurium-based device avoids these problems with elegant design. Nanowires naturally convert light into electrical signals without external power, and their functions are more like biological photoreceptors. “The long-term success of these technologies depends on developing cost-effective solutions and ensuring their availability to a wider range of patients.”
What makes this approach particularly compelling is material choice. Tellurium is a silver-white semiconductor component with unique characteristics that enable it to respond to visible and infrared light. The researchers built the nanowires into an interlaced network that could easily be implanted into the subretinal space.
Impressive performance metrics
The device achieves excellent technical specifications, which distinguishes it from the prior art. Dental nanowires produce photocurrent density up to 30 amps, the highest reported in any retinal prosthetic material. Equally important, the device responds to wavelengths ranging from visible light to 1550 nanometers in the near-infrared spectrum, far beyond the range of previous methods.
In blind mice, implants trigger the activity of the optic nerve and visual cortex when exposed to light. The animals showed improved student response and performed better on pattern recognition tests, ultimately matching the mice’s performance to normal vision. Crucially, these improvements occur at nearly 80 times the light intensity threshold of nearly 80 times.
Infrared vision opens up new possibilities
The ability to detect infrared light is particularly valuable for vision recovery. Infrared provides better contrast in low-light conditions and can help patients navigate in the dark. Certain animals, such as certain snakes, naturally have this ability and use it to assess their environment more accurately.
The research team conducted extensive testing of this infrared sensitivity. Blind mice with implants can use 940 nanometer infrared illumination to locate the LED lights and identify geometric patterns – wavelengths that are completely invisible to normal mammalian eyes. In behavioral tests, the correct response rate of these mice when detecting infrared signals was about 67%, compared with only 12% in normal mice.
Safety and biocompatibility
Extensive tests have shown that the implant is well tolerated by biological tissues. In a 60-day mouse study, the researchers found no significant difference in the number of retinal cells between implanted and non-implanted areas. Although some initial immune cell activity was detected, this problem was resolved within two weeks after implantation.
Primate research provides more confidence in the safety of the technology. Carnivorous macaques monitored 112 days after implantation showed no signs of retinal damage, bleeding, or abnormal tissue changes. Importantly, the implant remained stable and maintained close contact with retinal tissue throughout the observation period.
Technological innovation
What makes this wide spectrum response lies in the asymmetry of the nanowires. The researchers found that when light hits a material, internal defects and external interface effects work together to generate powerful currents. Through quantum transmission simulations, they demonstrate how these asymmetric ways can break the natural symmetry of the material and achieve efficient light-to-inductance conversion over a wide wavelength range.
A particularly noteworthy finding not highlighted in the initial report involves the temporal response characteristics of the device. The implant successfully tracks the flickering light at a frequency of up to 12 Hz, with the optimal response being approximately 4 Hz. This temporal resolution matches the resolution of normal retinal function, suggesting that artificial systems can integrate well with existing neural pathways.
Looking to the future
Although these results are encouraging, there are significant challenges before the human trial begins. The researchers acknowledge that the overall photosensitive of its devices is still much lower than that of natural photoreceptors. This means that patients may need assistive technologies, such as specialized goggles to optimize performance.
The team also noted that visual cortical plasticity varies between species, and the extent to which human patients can adapt to restore vision is unclear. Previous research has shown that motion processing may be more powerful than shape recognition after long-term visual deprivation.
Despite these challenges, this work represents a meaningful advancement in artificial vision technology. By combining vision recovery with infrared sensitivity in devices that do not require external power, the researchers have created a platform that can ultimately blind or impair visual impairment in an estimated 285 million people worldwide.
Successful demonstrations in rodent and primate models lay the foundation for future clinical development, possibly providing patients with restored vision, but rather enhancing the visual ability of normal perception in humans.
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