In a groundbreaking study, researchers have successfully made the skin on the skulls and abdomens of live mice transparent by applying a mixture of water and a common yellow food coloring called tartrazine. This innovative approach was led by Dr. Zihao Ou, an assistant professor of physics at The University of Texas at Dallas, and the results were published in the journal Science. Living skin is typically opaque due to its scattering of light, similar to fog, making it impossible to see through. By combining the light-absorbing properties of tartrazine with skin, the researchers were able to achieve transparency by reducing light scattering in the tissue.
The yellow dye molecules in the water solution change the refractive index of the skin tissue in a way that matches components like lipids, ultimately reducing the degree to which light scatters in the skin. When the solution was applied to the mouse skin, it caused the skin to become transparent after the dye diffused into the tissue. This process is reversible, and the dye is metabolized and excreted through urine. Through the transparent skin, researchers were able to observe blood vessels on the surface of the brain and internal organs in the abdomen of the mice. Although the transparent areas took on an orange color, the dye used in the solution is commonly used in food and is considered safe for living organisms.
While the researchers have not yet tested this process on humans, they believe it could have significant applications in biomedical research. By making tissue transparent, researchers could use optical imaging techniques to study more detailed dynamics of living organisms. This advancement has the potential to revolutionize existing optical research in biology and improve current research methods. The technique has the potential to make medical diagnosis platforms more accessible and affordable to a broader audience.
In the future, the researchers aim to understand what dosage of the dye molecule would work best in human tissue and to experiment with other molecules that may perform more efficiently than tartrazine. The research was funded by federal agencies such as the National Institutes of Health, the National Science Foundation, and the Air Force Office of Scientific Research, with the researchers having applied for a patent on the technology. Dr. Zihao Ou plans to continue this research in his Dynamic Bio-imaging Lab at UTD, exploring potential applications in improving existing optical imaging technologies and advancing biomedical research.