2024-09-10 22:59:10
Through timely implementation of s live mouse common food coloring – tartrazine–, which strongly absorbs light, researchers at Stanford University (USA) succeeded in making its tissues transparent.
Therefore they were able to look at the blood vessels of the scalp and surface of the brainthe movement of the organs that are located under the skin of the abdomen and small contracting units the muscle work. Details are published this week in the magazine Science.
Through the transparent skin of the mouse, the blood vessels of the scalp and the movement of the organs in the abdomen are visible.
The water-soluble dye (known as FD&C Yellow 5 in the United States, yellow 5 in Latin America and additive E 102 in the European Union) is often used in chips as an appetizer, the toppings candy and other orange or yellow foods.
The researcher Zihao Ou has a vial with the yellow food coloring tartrazine in solution. / University of Texas at Dallas
The authors put this color together, a absorbs most of the blue and ultraviolet lightwith a light scattering medium such as the skin. Separately, these two components block most of the light rays, but when they are combined, the transparency of the outer tissue that covers the animal is achieved.
The skin became transparent after applying the tartrazine dye dissolved in water, a reversible and safe process
“It’s a complex mixture of biological tissue water (with a low refractive index) and biomolecules such as lipids and proteins (having a high refractive index); and as with a mixture of water and oil, the light is scattered in all directions as it propagates through the tissue, resulting in optical opacity,” the lead author explains to SINC, Zihao Ouwho is straight from Stanford as a professor of Physics at the University of Texas at Dallas.
“But when molecules that absorb light strongly, such as tartrazine, are introduced into this aqueous medium, the refractive index of the solution increases at certain wavelengths (according to mathematical equations called Kramers-Kronig relationship) and refractive index differences in biological tissues are greatly reduced. this reduces light diffusion in tissues biological and becomes visually transparent.”
Basically, the dye molecules reduce the level of light scattering in skin tissue, like dispersing a fog bank.
After the application of dissolved tartrazine, blood flow was observed on the surface of the living mouse brain. The skin transparency effect is reversible and disappears after the color is removed. / Stanford University/Gail Rupert/USNSF
Researchers have discovered the benefits of tartrazine and other absorbent molecules to achieve transparency from basic knowledge of the field of optics and doing prophecy on how light interacts with colored biological tissues.
Transparent chicken breast
They first tested their predictions on thin slices of chicken breast. As the concentration of the dye increased, the refractive index of the fluid within the muscle cells increased, until it matched the refractive index of the muscle proteins. As a result, the slice became transparent.
A slice of chicken breast that goes from the typical opaque appearance of the meat to transparency after immersion in a tartrazine solution. / Hong Lab and the Brongersma Lab at Stanford University/AAAS
Then, in their experiments with mice, the authors rubbed the solution of water and tartrazine on the skin of their heads and abdomens. When the color has completely diffused into that fabric, when, in a few minutesthis became transparent, albeit with an orange tone.
Temporary and reversible effect
The transparency effect is temporary and reversible, since can be removed with a quick wash of the color. The amount that penetrates the skin metabolized and eliminated through urine. Unlike other methods used to increase transparency, these substances do not harm living animals.
Thus, through the transparent skin of the mouse’s skull, the researchers were able to directly see the blood vessels on the surface of the brain. In the abdomen, they noticed the internal organs and the peristalsisthe muscle contractions that move the material through the digestive tract.
Scientists have made the skin on the head and abdomen of live mice transparent by applying a mixture of water and a common yellow food coloring called tartrazine to those areas. / Zihao Ou/BioRender.com
“It is important that the coloring biocompatiblethat is, safe for living organisms,” says Ou, who, in addition, emphasizes that “it is very cheap and effective: we don’t need much of it for it to work.”
Future performance in humans
The authors have not yet tested the process i human skinwhich is about 10 times thicker than a mouse, but it could be done in the future. At this time it is not clear what dose of dye or what method of administration would be necessary to overcome the total thickness.
“The basic physics which is the basis of the same optical opacity between human and mouse skin,” emphasizes the Professor, “and we predict that there is no necessary limit to the application of our invention to humans. What is needed is a drug administration strategy and a recipe design more efficient and precise to achieve optimal imaging conditions with minimal adverse effects.”
The researcher hopes that it will be one of the first applications of the technique to improve the present research methods in optical imaging: “When we saw the results of our experiment we immediately thought about how this could improve biomedical research. Optical equipment, such as the microscope, is not used directly to study living people or animals because light cannot pass through living tissue. But now that we can make the fabric transparent, it will allow us to observe more detailed dynamics. “It will completely revolutionize current optical research in biology.”
“Other than that,” he continues, “because of his character non-invasive unique, it will also allow investigations into chronic biological issues that last for a relatively long time, for example cancer metastasis and the Alzheimer’s disease. In addition, we predict that this invention could be applied clinically for early diagnosis of other pathologies and health monitoring in humans.”
He also remembers that many medical diagnostic platforms are expensive and inaccessible to a wide audience, “but those based on our technology should not be.”
The next steps
The next stages of the investigation will consist of determine which dose the dye molecule may work better in human tissues. On the other hand, the authors are already experimenting other moleculesincluding artificial materials, which may be more effective than tartrazine.
This study was funded by US federal agencies such as the National Institutes of Health (NIH), the National Science Foundation (NSF), and the Air Force Office of Scientific Research. The authors have already asked the patent of this technology.
Demonstration of skin tissue becoming transparent when the dissolved dye is applied, including reflection of photon pathways from unstained tissue. / Keyi “Onyx” Li/US National Science Foundation
#Yellow #color #living #animals #transparent