Nanotechnology makes it possible for mice to see in infrared

Mice with vision enhanced by nanotechnology were able to see infrared light as well as visible light, reports a study published February 28 in the journal Cell. A single injection of nanoparticles in the mice's eyes bestowed infrared vision for up to 10 weeks with minimal side effects, allowing them to see infrared light even during the day and with enough specificity to distinguish between different shapes.

These findings could lead to advancements in human infrared vision technologies, including potential applications in civilian encryption, security, and military operations.

Humans and other mammals are limited to seeing a range of wavelengths of light called visible light, which includes the wavelengths of the rainbow. But infrared radiation, which has a longer wavelength, is all around us. People, animals and objects emit infrared light as they give off heat, and objects can also reflect infrared light.

"The visible light that can be perceived by human's natural vision occupies just a very small fraction of the electromagnetic spectrum," says senior author Tian Xue of the University of Science and Technology of China. "Electromagnetic waves longer or shorter than visible light carry lots of information."

In this study, the scientists made nanoparticles that can anchor tightly to photoreceptor cells and act as tiny infrared light transducers. When infrared light hits the retina, the nanoparticles capture the longer infrared wavelengths and emit shorter wavelengths within the visible light range. The nearby rod or cone then absorbs the shorter wavelength and sends a normal signal to the brain, as if visible light had hit the retina.