Super vision could be in sight for soldiers

An image showing nanoparticles binding to rods and cones

Mammals have photoreceptor cells known as rods and cones that recognise light with wavelengths in the visible spectrum and send signals to the brain. Colder temperatures are often given a shade of blue, purple, or green, while warmer temperatures can be assigned a shade of red, orange, or yellow.

Researchers from the University of Science and Technology, China, and the University of Massachusetts Medical School (UMass) in the USA, injected the rodents' eyes with a solution filled with nanoparticles. These findings could lead to advancements in human infrared vision technologies, including potential applications in civilian encryption, security, and military operations. Our eyes aren't equipped to see longer wavelengths of light given off at night, which includes near-infrared (NIR) and infrared (IR) light - both of which are all around us, like the heat people give off or objects that reflect infrared light. Once those particles were in a mouse's eye, the proteins guided them to photoreceptor cells in the retina, essentially glueing the particles to those cells.

The researchers tested the nanoparticles in mice, which, like humans, can not see infrared naturally.

This led to the mice developing infrared vision - without compromising their normal sight.

Mice, like humans, can not naturally see infrared, making them an ideal candidate for experimentation.

A single injection of nanoparticles in the mice's eyes bestowed infrared vision for up to 10 weeks.

Researchers found that those critters receiving injections showed unconscious physical signs of infrared light detection (like pupils constricting), while the control group didn't respond.

It may also lead to a revolutionary cure for people who are born colour blind, say the USA and Chinese team.

In rare cases, side effects did occur, leaving some mice with cloudy corneas, which disappeared in less than a week.

Illustration of the infrared-to-visible-light conversion process. Tests found no damage to the retina's structure, suggesting that the procedure is safe.

Prof Han said: "In the future, we think there may be room to improve the technology with a new version of organic-based nanoparticles, made of FDA (Food and Drug Administration) approved compounds, that appear to result in even brighter infrared vision". Human eyes have a retinal structure called the fovea, which has a much higher density of cones than rods, while mice have more rods than cones.

The full study was published this week in the journal Cell.

Added Prof Xue: "This is an exciting subject because the technology we made possible here could eventually enable human beings to see beyond our natural capabilities".



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