Welcome to DU!
The truly grassroots left-of-center political community where regular people, not algorithms, drive the discussions and set the standards.
Join the community:
Create a free account
Support DU (and get rid of ads!):
Become a Star Member
Latest Breaking News
Editorials & Other Articles
General Discussion
The DU Lounge
All Forums
Issue Forums
Culture Forums
Alliance Forums
Region Forums
Support Forums
Help & Search
Remember the visible human science kit?
Maybe you can be one yourself.
Common food dye found to make skin and muscle temporarily transparent
Researchers say procedure not yet tested on people could eventually be used to help locate injuries or tumours
https://www.theguardian.com/science/article/2024/sep/05/common-food-dye-found-to-make-skin-and-muscle-temporarily-transparent
Researchers have peered into the brains and bodies of living animals after discovering that a common food dye can make skin, muscle and connective tissues temporarily transparent.
Applying the dye to the belly of a mouse made its liver, intestines and bladder clearly visible through the abdominal skin, while smearing it on the rodent’s scalp allowed scientists to see blood vessels in the animal’s brain.
Treated skin regained its normal colour when the dye was washed off, according to researchers at Stanford University, who believe the procedure opens up a host of applications in humans, from locating injuries and finding veins for drawing blood to monitoring digestive disorders and spotting tumours.
“Instead of relying on invasive biopsies, doctors might be able to diagnose deep-seated tumours by simply examining a person’s tissue without the need for invasive surgical removal,” said Dr Guosong Hong, a senior researcher on the project. “This technique could potentially make blood draws less painful by helping phlebotomists easily locate veins under the skin.”
Applying the dye to the belly of a mouse made its liver, intestines and bladder clearly visible through the abdominal skin, while smearing it on the rodent’s scalp allowed scientists to see blood vessels in the animal’s brain.
Treated skin regained its normal colour when the dye was washed off, according to researchers at Stanford University, who believe the procedure opens up a host of applications in humans, from locating injuries and finding veins for drawing blood to monitoring digestive disorders and spotting tumours.
“Instead of relying on invasive biopsies, doctors might be able to diagnose deep-seated tumours by simply examining a person’s tissue without the need for invasive surgical removal,” said Dr Guosong Hong, a senior researcher on the project. “This technique could potentially make blood draws less painful by helping phlebotomists easily locate veins under the skin.”
Works fine on rodents.
Spoiler alert: tartrazine, a yellow food dye used in US Doritos, SunnyD drink and other products.
⚠️ Do not experiment with this stuff. Wouldn't hurt to avoid Doritos and SunnyD as well. California just banned 4 food additives.
https://www.npr.org/2023/10/10/1204839281/california-ban-food-additives-red-dye-3-propylparaben-candy
brominated vegetable oil, potassium bromate, propylparaben and red dye 3 will be banned effective 2027.
18 replies
= new reply since forum marked as read
= new reply since forum marked as read
I can use some of my graphics magic.
Webmasters better not mess with me!
Done.
https://www.science.org/doi/10.1126/science.adm6869
Achieving optical transparency in live animals with absorbing molecules
ZIHAO OU, YI-SHIOU DUH, [...], AND GUOSONG HONG +18 authors
SCIENCE
6 Sep 2024
Vol 385, Issue 6713
DOI: 10.1126/science.adm6869
Editor’s summary
Optical imaging of biological tissues is hindered by the scattering and, to a lesser extent, absorption of light that limits the penetration depth. Ou et al. addressed this problem through an approach that at first may seem counterintuitive: the introduction of highly absorbing molecules (see the Perspective by Rowlands and Gorecki). The authors show that the addition of common dye molecules that absorb in the near ultraviolet and blue regions improve optical transparency in nearby longer wavelengths. In essence, by causing sharp absorption in the blue region, the refractive index in the red part of the spectrum is increased without increasing absorption. The addition of tartrazine was able to make the skin of a live rodent temporarily transparent. —Marc S. Lavine
Structured Abstract
INTRODUCTION
A challenge in trying to image biological matter is that its complex structure causes opacity because of unwanted light scattering. This scattering results from refractive index mismatches among the components of biological tissues, limiting the penetration depth of optical imaging. The desire to see inside biological tissue and uncover the fundamental processes of life has spurred extensive research into deep-tissue optical imaging methods, such as two-photon microscopy, near-infrared-II fluorescence imaging, and optical tissue clearing. However, these methods either lack sufficient penetration depth and resolution or are unsuitable for living animals. Therefore, the ability to achieve optical transparency in live animals holds promise for transforming many optical imaging techniques.
[...]
RESULTS
Following our theory, we found that an aqueous solution of a common food color approved by the US Food and Drug Administration, tartrazine, has the effect of reversibly making the skin, muscle, and connective tissues transparent in live rodents. We conducted experiments in both tissue-mimicking scattering hydrogels and ex vivo biological tissues. These tests confirmed the mechanism underlying our observations and showcased the achievable spatial resolution down to the micrometer level through millimeters of scattering medium once transparency is attained. By using absorbing dye molecules, we can transform the typically opaque abdomen of a live mouse into a transparent medium. This “transparent abdomen” allows for direct visualization of fluorescent protein–labeled enteric neurons, capturing their movements that mirror the underlying gut motility in live mice. This enabled us to generate time-evolving maps that depict mouse gut motility and the diversity of movement patterns. To demonstrate the generalizability of this approach, we also applied dye solutions topically to the scalp of a mouse head for visualizing cerebral blood vessels and to the mouse hindlimb for high-resolution microscopic imaging of muscle sarcomeres.
CONCLUSION
Overall, we report the counterintuitive observation that strongly absorbing molecules can achieve optical transparency in live animals. The Lorentz oscillator model, which underlies this unusual observation, predicts that molecules with low resonance frequencies (long absorption wavelengths), sharp absorption peaks, and rich delocalized electrons are more effective candidates at raising the refractive index of the aqueous medium than are conventional optical clearing agents. Our approach also presents opportunities for visualizing the structure, activity, and functions of deep-seated tissues and organs without the need for surgical removal or the replacement of overlying tissues with transparent windows. Some limitations remain for this method, including reduced but not eliminated scattering owing to the challenge of matching refractive indices in heterogeneous tissues and achievable penetration depth depending on the diffusion of absorbing molecules.
Achieving optical transparency in live mice with absorbing dye molecules.
Strongly absorbing molecules dissolved in water can modify the RI of the aqueous medium through the Kramers-Kronig relations to match that of lipids. This approach can render various samples transparent, including scattering phantoms, chicken breast tissue, and live mouse body for visualizing a wide range of deep-seated structures and activities. Scale bars, 5 mm. [The schematic was prepared using BioRender.com]
[...]
ZIHAO OU, YI-SHIOU DUH, [...], AND GUOSONG HONG +18 authors
SCIENCE
6 Sep 2024
Vol 385, Issue 6713
DOI: 10.1126/science.adm6869
Editor’s summary
Optical imaging of biological tissues is hindered by the scattering and, to a lesser extent, absorption of light that limits the penetration depth. Ou et al. addressed this problem through an approach that at first may seem counterintuitive: the introduction of highly absorbing molecules (see the Perspective by Rowlands and Gorecki). The authors show that the addition of common dye molecules that absorb in the near ultraviolet and blue regions improve optical transparency in nearby longer wavelengths. In essence, by causing sharp absorption in the blue region, the refractive index in the red part of the spectrum is increased without increasing absorption. The addition of tartrazine was able to make the skin of a live rodent temporarily transparent. —Marc S. Lavine
Structured Abstract
INTRODUCTION
A challenge in trying to image biological matter is that its complex structure causes opacity because of unwanted light scattering. This scattering results from refractive index mismatches among the components of biological tissues, limiting the penetration depth of optical imaging. The desire to see inside biological tissue and uncover the fundamental processes of life has spurred extensive research into deep-tissue optical imaging methods, such as two-photon microscopy, near-infrared-II fluorescence imaging, and optical tissue clearing. However, these methods either lack sufficient penetration depth and resolution or are unsuitable for living animals. Therefore, the ability to achieve optical transparency in live animals holds promise for transforming many optical imaging techniques.
[...]
RESULTS
Following our theory, we found that an aqueous solution of a common food color approved by the US Food and Drug Administration, tartrazine, has the effect of reversibly making the skin, muscle, and connective tissues transparent in live rodents. We conducted experiments in both tissue-mimicking scattering hydrogels and ex vivo biological tissues. These tests confirmed the mechanism underlying our observations and showcased the achievable spatial resolution down to the micrometer level through millimeters of scattering medium once transparency is attained. By using absorbing dye molecules, we can transform the typically opaque abdomen of a live mouse into a transparent medium. This “transparent abdomen” allows for direct visualization of fluorescent protein–labeled enteric neurons, capturing their movements that mirror the underlying gut motility in live mice. This enabled us to generate time-evolving maps that depict mouse gut motility and the diversity of movement patterns. To demonstrate the generalizability of this approach, we also applied dye solutions topically to the scalp of a mouse head for visualizing cerebral blood vessels and to the mouse hindlimb for high-resolution microscopic imaging of muscle sarcomeres.
CONCLUSION
Overall, we report the counterintuitive observation that strongly absorbing molecules can achieve optical transparency in live animals. The Lorentz oscillator model, which underlies this unusual observation, predicts that molecules with low resonance frequencies (long absorption wavelengths), sharp absorption peaks, and rich delocalized electrons are more effective candidates at raising the refractive index of the aqueous medium than are conventional optical clearing agents. Our approach also presents opportunities for visualizing the structure, activity, and functions of deep-seated tissues and organs without the need for surgical removal or the replacement of overlying tissues with transparent windows. Some limitations remain for this method, including reduced but not eliminated scattering owing to the challenge of matching refractive indices in heterogeneous tissues and achievable penetration depth depending on the diffusion of absorbing molecules.
Achieving optical transparency in live mice with absorbing dye molecules.
Strongly absorbing molecules dissolved in water can modify the RI of the aqueous medium through the Kramers-Kronig relations to match that of lipids. This approach can render various samples transparent, including scattering phantoms, chicken breast tissue, and live mouse body for visualizing a wide range of deep-seated structures and activities. Scale bars, 5 mm. [The schematic was prepared using BioRender.com]
[...]
