Nanoparticle eye drops give mice night vision
Sci-fi aficionados will likely be familiar with the 2000 film Pitch Black, in which Vin Diesel plays a character with predator-like night vision. Well, such a scenario has come a step closer to reality, with scientists enabling mice to temporarily see near-infrared (NIR) light.
Mammals such as humans are only capable of visually processing light in the visible spectrum, hence its name. Researchers at the University of Massachusetts Medical School, however, wanted to find out if it was possible to extend that capability farther, allowing mice to visually detect longer wavelength infrared light that is given off by objects in both bright and dark environments.
To that end, they produced nanoparticles made of lectin proteins, which were delivered into the animals' eyes within liquid droplets. 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 nanoparticles subsequently served as nanoantennae, reacting to incoming NIR light (the shortest infrared wavelength) by converting it into visible green light that was detected by the photoreceptors.
In lab tests, it was determined that the mice were fully capable of differentiating between (and reacting to) different patterns of NIR light, produced by a lamp. Their ability to see visible light apparently remained unaffected, with the ability to perceive NIR light wearing off after two weeks – no adverse side effects were observed.
"With this research, we've broadly expanded the applications of our nanoparticle technology both in the lab and translationally," said Assoc. Prof. Gang 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."
A paper on the research, which also involved scientists from the University of Science and Technology of China, was recently published in the journal Cell.