Science Magazine: Invisibility, will this scientific fantasy become reality?

Author: Li Chuanfu Shi Xiangqi

In the hall of science fiction, "The Invisible Man" by Wells, the British science fiction master, is undoubtedly a classic. The protagonist uses a mysterious serum to make his cell refractive index match that of the surrounding air, thus achieving the effect of invisibility. This is not only a fascinating story, but also a bold attempt at scientific fantasy. However, who would have thought that after 127 years, this fantasy would gradually become a reality in a scientific laboratory.

Recently, Professor Guosong Hong of Stanford University published a groundbreaking paper in the journal Science, demonstrating for the first time how to use the pigment molecule tartrazine to make certain tissues of living animals transparent.

Screenshot of the paper: Science

Tartrazine is a synthetic pigment widely used in the food industry. At high doses, tartrazine has been shown to be non-toxic and able to reduce light scattering in the red spectral region, achieving optical transparency. By applying tartrazine topically to the scalp, abdomen, and hind limbs of mice, the researchers were able to clearly observe the brain vascular structure, visceral movements, and myotomes of the mice.

Tartrazine achieves this effect because it can change the refractive index of the aqueous medium to match the high refractive index of the tissue component. This adjustment of the refractive index reduces the scattering of light, making the tissue transparent. This discovery overturns traditional research on optical transparent agents and points to the potential of tartrazine in improving optical transparency.

The physical mechanism of achieving optical transparency using absorbing molecules Source: Science

By constructing a scattering model and using isolated chicken breast tissue, the researchers verified the mechanism by which lemon yellow improves optical transparency. They found that lemon yellow not only improves imaging resolution, but also enables high-resolution microscopic imaging in thicker tissues. In addition, by transparentizing the abdomen of mice, the researchers were able to monitor the dynamic movement of the intestine in real time, which is of great significance for studying intestinal function and the enteric nervous system.

This research is not only innovative in theory, but also shows great potential in practical application. Topical application of tartrazine has low toxicity and the transparent effect can be reversed by washing with water, which provides a safe and reversible method for in vivo tissue imaging.

From Wells's "The Invisible Man" to today's scientific laboratories, we have witnessed the process of a scientific fantasy gradually becoming a reality. This research not only gives us a deeper understanding of optical transparency, but also provides new possibilities for future biomedical imaging technology. With the continuous advancement of science and technology, we have reason to believe that the invisible man may no longer be an unattainable dream.