Common Food Dye Can Make Skin Invisible Under The Right Conditions
Image via Keyi “Onyx” Li/U.S. National Science Foundation / EurekAlert (public domain)
Researchers from the University of Texas at Dallas and Stanford University have stumbled upon a technique that temporarily makes living tissue transparent. It turns out a common food dye, usually found coloring your favorite snacks, might help you peer into your body’s true colors.
Tartrazine, better known as FD & C Yellow 5, is an ubiquitous food coloring typically responsible for the vibrant hue of candies and chips, but it’s now showing potential in the medical field.
The study, published in the journal Science and backed by the US National Science Foundation, demonstrates how applying tartrazine to skin alters its refractive index, essentially creating “a window into the body.” When tested on mice, the dye allowed scientists to observe blood vessels and internal organs without resorting to invasive procedures. The effect is akin to dissipating a fog bank, reducing the scattering of light within the skin and revealing the structures beneath.
This breakthrough didn’t happen by accident. The research team developed a method to predict how light interacts with dyed biological tissues, diving deep into the complexities of light scattering and refraction. They realized that dyes most effective at absorbing light could also be highly effective at directing it uniformly through various refractive indices. This insight led them to tartrazine, which proved to be the perfect candidate for achieving tissue transparency.
Seeing through skin?
— U.S. National Science Foundation (@NSF) September 5, 2024
Researchers @Stanford discovered a simple way to make skin reversibly transparent, revealing organs, blood flow and even digestion in sleeping animals. Published today @ScienceMagazine, learn more: https://t.co/OACIIz3IOa pic.twitter.com/iiC2meA3WO
“Looking forward, this technology could make veins more visible for the drawing of blood, make laser-based tattoo removal more straightforward, or assist in the early detection and treatment of cancers,” details Stanford University assistant professor of materials science and engineering Guosong Hong.
“For example, certain therapies use lasers to eliminate cancerous and precancerous cells, but are limited to areas near the skin’s surface. This technique may be able to improve that light penetration.”
Image via Keyi “Onyx” Li/U.S. National Science Foundation / EurekAlert (public domain)
However, it’s important to note that this technique hasn't been tested on humans yet. The researchers first validated their predictions using thin slices of chicken breast, observing increased transparency as tartrazine concentrations rose. They then gently applied a temporary tartrazine solution to mice, revealing blood vessels in the brain and abdominal movements caused by heartbeats and breathing.
While the idea of recreating an invisibility cloak without a need for a cloak is intriguing, there’s still work to be done before this method moves from the lab to the clinic.
[via Gizmodo and Interesting Engineering, images via Keyi “Onyx” Li/U.S. National Science Foundation / EurekAlert (public domain)]
