Nanotechnology Could Give Humans Infrared Vision

Nanotechnology may soon give humans infrared vision, according to a new study that successfully achieved this with mice. This could open up a new door in human infrared technologies with applications extending to security and military operations, scientists from the University of Science and Technology of China said.

The study, published this week in the journal Cell, documented how mice were able to see infrared light for up to 10 weeks after being given a single injection of nanoparticles into their eyes. Humans and other mammals are only able to see certain wavelengths of light called visible light. Both ultraviolet and infrared light falls outside of this range. Infrared radiation is all around us, emitted from people, animals and objects.

"The visible light that can be perceived by human's natural vision occupies just a very small fraction of the electromagnetic spectrum," said senior author Tian Xue who, along with a team of scientists, developed the nanotechnology to work with the eye's existing structures.

Gang Han at the University of Massachusetts Medical School, explained that "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." 

The human eye is unable to perceive infrared wavelengths because they are too long to be absorbed by photoreceptors but in this study, the team of scientists were able to make nanoparticles that could anchor tightly to photoreceptor cells. They ultimately serve as tiny infrared light transducers that capture the longer infrared wavelengths then emit shorter wavelengths that fall within the visible light range. The nearby rod then absorbs these wavelengths and sends abnormal signal to the brain.

The technology still needs to be fine-tuned but scientists hope to make it suitable for the human eyes.

"This is an exciting subject because the technology we made possible here could eventually enable human beings to see beyond our natural capabilities," said Xue.

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