Chinese scientists have used nanotechnology methods in experimental animals (mice), managing to improve their vision so that they do not only see the visible light, but also the infrared, which is normally invisible to humans and most animals.
The achievement paves the way for new advances in infrared vision technologies, as well as for military, security and encryption applications. At the same time, the question arises as to whether in the far future it will be possible even people – with the appropriate modifications in their eyes – to see the infrared without the need for a device.
The researchers, led by Tian Sue and Gin Bao of the University of Science and Technology of China, who published the journal Cell Biology (Cell), introduced nanoparticles into the eyes of the mice, which allowed the animals to acquire infrared vision for a while up to ten weeks, even the day, as well as minimal side effects.
Humans and other mammals can only see certain wavelengths of light, but not infrared, which has a longer wavelength than visible light. Infrared is everywhere around us, as humans, animals and objects, because of their heat, emit infrared light, while objects can also reflect infrared light.
“The visible light that can be perceived by people’s natural sight, occupies a very small part of the electromagnetic spectrum. But electromagnetic waves that are farther or shorter than visible light carry a lot of information, “said Sue.
When the light enters the eye and falls on the retina, the photoreceptor cells (the angle and the rods) absorb the photons with visible wavelengths of light and send the corresponding electrical signals to the brain. However, since infrared wavelengths are too large to be absorbed by photoreceptors, we are unable to see infrared.
Researchers have developed nanoparticles that can bind to eye cell photoreceptors and function in the same way but in infrared. When infrared light falls into the eye, nanoparticles can catch these longer wavelengths while the related signals are then sent to the brain.
The technology is based on converting infrared light to a shorter wavelength within the range of visible light. In the experiment with mice (which like humans can not see in infrared), the nanoparticles absorbed infrared light at a wavelength of 980 nanometers and turned it into 535 nm light, which made the infrared light look like a green color . Through various tests, scientists have confirmed that rodents could actually perceive infrared light.
“We believe that this technology can also work on human eyes, not only by creating a super vision, but also for new treatments for people who do not see the red color,” said Sue. “The new technology we developed can ultimately allow human beings to see beyond their physical abilities,” he added.
These nanoparticles could be integrated and improved with today’s infrared vision technology based on sensors and cameras, but it still has several limitations.