IMAGING THE BODY: Scientists discover ways to make mice “transparent”
KC Lovely Reyes
Common food dye may have the ability to revolutionize the medical field through its ability to make a living body transparent as tested on mice.
Tartrazine, widely known as Yellow No. 5, is found in various everyday products—neon-colored sodas, candies, chips, butter, and even certain drug tablets.
Approved by the Food and Drug Administration in limited quantities for food and cosmetics, its role could soon extend beyond coloring food into the realm of medical diagnostics.
When used outside the scope of being a mere dye, tartrazine opens the possibility for minimal usage of magnetic resonance imaging, computed tomography, and ultrasounds where devices are used to produce an image of the inside tissues to scan for diseases, abnormalities, and even during pregnancies.
Said physicist Zihao Ou at the University of Texas at Dallas, the dye was applied to mice, altering the optical properties of their tissues and making internal organs visible.
“One unique part about our strategy is that we are changing the optical properties of the tissue directly,” Ou explained, likening the effect to how microbubbles in water make it less transparent.
Proteins in rodents and humans have higher refractive indexes, and tartrazine minimizes light dispersion. This lemon-yellow dye reduces light scattering, allowing light to penetrate deeper, making tissues appear transparent for up to 20 minutes.
Previous attempts using glycerol and fructose were less effective. As Guosong Hong, a materials science engineer at Stanford University, noted, “These solutions were already transparent and not as colored compared to tartrazine.”
Although promising, the technique remains far from human trials. Human skin is about ten times thicker than that of mice, and factors such as allergies or skin sensitivities must be considered.
Still, the implications are vast. If successful, this dye could revolutionize not only how we detect diseases but also streamline surgeries and even simplify laser tattoo removal.
“We hope that with our initial work, there will be more follow up proposing new molecules that are going to be more efficient and safer for human application,” Ou said.