Point the super mouse. Scientists have created mice that can see infrared light normally invisible to mammals ̵
In order to do so, they inject into the eyes of rodent nanoparticles that turn infrared light into visible wavelengths 1 . Humans and mice, like other mammals, can not see infrared light that has wavelengths slightly longer than red light – between 700 nanometers and 1 millimeter.
But Tian Xue, a neurologist at the University of Science and Technology of China at Hefei, colleagues developed nanoparticles that turn infrared wavelengths into visible light. Nanoparticles absorb photons with a wavelength of about 980 nanometers and emit them at shorter wavelengths, about 535 nanometers, corresponding to green light. electrical pulses – and then injected them into mice
Researchers have shown that nanoparticles are successfully attached to photoreceptors, which in turn respond to infrared light by producing electrical signals and activating visual brain processing zones.
The team conducted experiments to show that mice actually detect and respond to infrared light.
In a test, they gave the mice a choice between a dark box and a "light" box with infrared light. Usually, mice – which are night – will be looking for the safety of a darker box. Ordinary mice showed no preference between the two boxes because they did not see the infrared light. But the modified mice prefer the dark box.
In another experiment, the team learned the two types of mice to bind green light with an electric shock, but the modified mice also froze in fear when infrared light enters. Finally, the researchers placed the rodents in a water labyrinth that had two hands lit by different light patterns, only one of which led to a hidden, dry shelter. Modified mice have chosen the right labyrinth arm according to the light pattern, regardless of whether the patterns are shown in visible or infrared light. – You show different mouse models you can not see – for you, it's just a blank screen. But the mouse can choose it correctly. "
Other groups also strive to give rodents vision of infrared vision. Eric Thomson, a neurologist at Duke University in Durham, North Carolina, has developed a system that allows rats to detect infrared light through four sensors connected directly to the brain . But the small number of sensors has provided only enough visual information for the rats to find the location of the light, Thomson says.
"What's really exciting here is that they've actually shown that they get real-image information," he says.
Sue says his technique can have several applications, including giving "supervision" to people. Visibility of infrared light can help people see at night by detecting infrared wavelengths emitted by or reflecting people and objects in the environment. This may be useful for military operations and security operations, for example.
The team hopes to adapt nanoparticles to transfer drugs for later release into the eye. But there are several obstacles, including safety concerns, before any human use can be tested.
For example, heavy metal nanoparticles and regulators would hardly have approved them for human use.
But not everyone believes that this technique can be used to increase human vision.
The human visual system has evolved over millions of years to be sensitive to a very specific part of the electromagnetic system, Glenn says. Jeffrey, a visual neurologist at London University College, and the retina is not used to seeing the infrared spectrum. It's not sure how people will interpret the image: the environment will look much brighter, for example, and the images can be enormous. So, although science is impressive from a technical point of view, Jeffrey says, it is unclear what their effect will be. Considering his concerns, he adds, "I am the last person in the world who would like to see an infrared connection."
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