Massachusetts University scientists claim to have given mammals night vision to see light beyond the visible spectrum and into the range of infrared light. The vision enhancement, done with a simple injection of nanoantennae, is temporary and doesn’t interfere with the animals’ ability to see visible light, they said, and could be used to explore neural brain networks and assist with vision repair.
“With this research, we’ve broadly expanded the applications of our nanoparticle technology,” said associate professor of biochemistry & molecular pharmacology, Dr Gang Han. “These nanoantennae will allow scientists to explore a number of intriguing questions, from how the brain interprets visual signals to helping treat colour blindness.”
A typical mammalian eye will see wavelengths from about 400 to 700 nanometers (the so-called visible spectrum). However, the human eye is unable to see longer wavelength light, such as near infrared (NIR) or infrared light, or to project an NIR image to the brain without the aid of complicated and cumbersome electronic devices, such as night vision goggles.
Dr Han and his colleagues at the University of Science and Technology of China developed a lectin protein conjugated nanoparticle that can be delivered in droplets. These proteins guide the nanoantennae and “glue” them to the outside of retinal photoreceptors in mice. Once anchored on the cells, these microscopic antennae convert NIR into visible, green light. The green light is observed by the retinal cell and images are sent and interpreted by the brain as visible light.
The researchers developed a series of tests to verify mice treated with the nanoparticles can not only perceive NIR light, but also get NIR pattern vision and are able to differentiate between sophisticated shape patterns such as triangles and circles. Treated mice perceived these light patterns even in daylight conditions, indicating the nanoparticles were working in parallel with conventional vision. After two weeks, the ability wore off and the nanoparticles left no lingering effects to the mice or their vision, said Dr Han.
