PREVIEW

Scientists at a US university have developed a new way to see body organs using food-safe dye to make tissues transparent.

The innovative method involves applying a food-safe dye, tartrazine (also known as FD&C Yellow 5), to tissues, allowing for a clearer view of internal organs.

The process is reversible and has been tested on animal subjects, showing potential applications in a variety of medical fields, from detecting injuries to identifying cancers. Stanford University researchers published the research ″Achieving optical transparency in live animals with absorbing molecules″ in the September 6, 2024, issue of Science.

Assistant Professor Guosong Hong, a lead researcher and National Science Foundation (NSF) CAREER grantee, noted the far-reaching implications of this discovery. "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," Hong said. He also explained that this technique could improve laser therapies used to eliminate cancerous cells by enhancing light penetration into deeper tissues.

The method works by matching the refractive index of biological tissues, allowing light to pass through without scattering. The researchers tested the process on animal tissues by applying tartrazine to the skin of mice, successfully rendering tissues transparent and revealing underlying structures like blood vessels and intestines. Importantly, the transparency effect was temporary and reversible, with no long-term side effects observed.

The team’s research builds on foundational principles in optics, applying them to biological tissues for the first time. The ability to use strong dyes to match refractive indices represents a breakthrough in biomedical imaging, and researchers believe further studies could unlock even deeper views into the body.

Graduate researcher Nick Rommelfanger and postdoctoral researcher Zihao Ou, the study’s lead author, played key roles in transitioning from theoretical predictions to experimental success. The project, supported by NSF grants and other funding bodies such as the U.S. National Institutes of Health, has opened up new possibilities for using optics in medicine.

"NSF’s support played an instrumental role in the success of this work," said Hong, who emphasised the importance of early funding in enabling the team to pursue this groundbreaking research.

While the technique shows great promise, it has not yet been tested on humans. Researchers caution that dyes should not be consumed or misused without proper safety protocols.