Study with mice initially
The injection of nanoparticles allows for night vision
Night vision without a night vision device – what sounds like science fiction may soon become reality. The researchers are able to make mice see in the near infrared by injecting nanoparticles into their eyes. Similar nanoparticles could also help people with poor vision and eye disease.
Humans can only see light in a limited range of frequencies. Lower frequencies such as infrared are not visible to our eyes because photoreceptors do not respond to them. Technologies such as night vision goggles make this frequency range visible, for example by converting near infrared into visible light. But it could also work without it, as one study shows.
Scientists from the University of Massachusetts Medical School and the University of Science and Technology of China have developed nanoparticles that mice can use to see at night. For their study, published in the trade journal “Cell,” Gang Han’s team injected nanoparticles under the retina of the rodents. The bloodstream then carries the nanoparticles to the eye. There, these so-called nano-antennas bind to photoreceptors, that is, the cells that are responsible for the perception of light. This allows the eye to respond to near infrared light, which does not normally activate a signal.
According to the study, a series of experiments showed that mice could actually see in this frequency range: if, for example, near-infrared light was radiated into the eye, only the pupils of the injected mice narrowed, while the pupils of the control the group did not react. In the injected mice, near-infrared light also activated the visual cortex, which is responsible for visual perception in the brain. Further investigation also showed that the ability to see at night apparently not sight altered in visible light.
Night vision without complicated devices
The anchored particles expand the visible light spectrum so that animals can perceive near-infrared from the non-visible range, the researchers write. The brain then processes this information and interprets it as an image. “This is done without the help of complicated equipment,” says the study. After the injection, the effect lasted up to two months.
Furthermore, this procedure appears to be relatively safe. Side effects were rare in test animals. According to the scientists, some animals’ corneas fogged up after the injection, but this disappeared on its own within a week.
“We therefore believe that this technology also works for the human eye,” said study lead author Tian Xue. “In our experiment, the nanoparticles absorbed infrared light at a wavelength of 980 nanometers and converted it to light at 535 nanometers.” Light with a wavelength of 535 nanometers is visible to the human eye and is perceived as green.
According to the researchers, it is conceivable that nanoparticles could be used not only to improve human vision, but also to treat visual disturbances and eye diseases. “With this research, we have greatly expanded the applications of nanoparticle technology. With a little help, we may have the ability to see all the hidden information of NIR and IR radiation in the universe that is not visible to our naked eyes,” summarizes L ‘author of the Han Gang study.