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A multidisciplinary team of researchers has just given mice “night vision” by inserting nanoparticles into their beady little eyes – and it could potentially be applied to humans someday.
Cue superhero music.
A new paper published in Cell describes the technology, which uses a simple injection containing nanoantennae – nanoscopic electromagnetic collectors designed to absorb specific wavelengths – to enable the mice to see beyond their current visible spectrum of light. The whole process is temporary and wears off after about two weeks without lingering effects. Plus, the injection works with structures already found in the eye and had no effect on rodents’ ability to see during the day.
In a nutshell, most mammals can only see a very small percentage of the electromagnetic spectrum, equating to wavelengths from 400 to 700 nanometers or the colors of the rainbow. 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.
"When light enters the eye and hits the retina, the rods and cones – or photoreceptor cells – absorb the photons with visible light wavelengths and send corresponding electric signals to the brain," said study author Gang Han in a statement. "Because infrared wavelengths are too long to be absorbed by photoreceptors, we are not able to perceive them."
That’s where “lectin conjugated nanoparticles” come into play. Delivered via droplets, these proteins guide the nanoantennae and “glue” them to the outside of retinal photoreceptors in the eyes of mice. Once anchored to the photoreceptor cell, they convert NIR into visible green light that can then be observed by the retinal cell. The rod or cone then absorbs the shorter wavelengths and sends them to the brain for translation.
“With this research, we’ve broadly expanded the applications of our nanoparticle technology both in the lab and translationally,” said Han. “These nanoantennae will allow scientists to explore a number of intriguing questions, from how the brain interprets visual signals to helping treat color blindness.”
You may be asking yourself how one can tell whether or not a mouse sees at nighttime. Simple: laboratory testing. Researchers noticed that mice injected with the nanoparticles exhibited unconscious reactions to infrared light, such as their pupils constricting. They were also able to distinguish between different shapes, such as triangles and circles, found throughout a maze in the same way that they could during the daylight.
Besides the whole superhuman capability, the researchers say their work presents an opportunity to explore neural networks in the brain and potentially assist with vision repair.
“We believe that this research is a major advance in the field of biotechnology. This concept-provoking study should pave the way to numerous critical applications via the unique creation of mammalian NIR visual ability and have high translational potential,” said Han. “Moreover, it is very likely that the sky may look very differently both at night and in daytime. We may have the capability to view all the hidden information from NIR and IR radiation in the universe which is invisible to our naked eyes.”
