Mice are already masters of lurking in the shadows, far from curious human eyes, but researchers in the US and China have only made a few of them into serious superheroes. The mice, which are usually equipped with eyes that can see only visible light, like humans, have instead been given the ability to see near infrared light, effectively allowing them to see in the dark.
By injecting specially designed nanoparticles directly In the eyes of the mice, the animals showed the ability to see near infrared light. More remarkably, the vision augmentation does not seem to have adversely affected the daylight vision of the mice.
The study, published in a recent article in the journal Cell focused on the formulation of special nanoparticles that convert near infrared light into a greenish visible light. The particles adhere to the photoreceptors in the animals' eyes, and when they are hit by infrared light, a signal is generated which, like the visible light, is sent to the animal's brain.
"When light enters the eye and the retina hits the rods and cones ̵
Injecting the mice is a workaround for this deficiency and promotes compatibility between visible and infrared photoreceptors.
Mice prefer the dark, and the uninjected mice showed no preference between the completely dark chamber and the one with infrared light, as they simply can not see it. However, the modified mice did not like the infrared light bin, which indicated that they actually saw the infrared light.
The team suggests that something similar could even work well in humans. The nanoparticles will remain in their eyes for up to two months without any obvious negative effects, and although they may not yet be ready to push needles into human eyes, the day may not be far off.