Using tattoo ink to find cancer

Date:
September 2, 2020
Source:
University of Southern California
Summary:
The humble ink in a tattoo artist's needle could be the key to
improving the detection of cancer. Researchers recently developed
new imaging contrast agents using common dyes such as tattoo ink
and food dyes. When these dyes are attached to nanoparticles,
they can illuminate cancers, allowing medical professionals to
better differentiate between cancer cells and normal adjacent cells.



FULL STORY ==========================================================================
The humble ink in a tattoo artist's needle could be the key to improving
the detection of cancer, thanks to new research from the USC Viterbi
Department of Biomedical Engineering.


==========================================================================
WiSE Gabilan assistant professor in the department with a lab at the USC Michelson Center for Convergent Bioscience, Cristina Zavaleta and her team recently developed new imaging contrast agents using common dyes such as
tattoo ink and food dyes. When these dyes are attached to nanoparticles,
they can illuminate cancers, allowing medical professionals to better differentiate between cancer cells and normal adjacent cells. The work
has been published in Biomaterials Science.

Early detection is crucial for patients to have the best possible outcomes
from cancer; a disease that will affect over 38% of Americans at some
point in their lifetime.

However, detection is challenging without good imaging agents; contrast materials which when injected into patients, allow for imaging such as
MRI and CT to function with better sensitivity and specificity, enabling medical professionals to diagnose with accuracy, and for surgeons to
identify the exact margins of tumors.

"For instance, if the problem is colon cancer, this is detected via
endoscopy," Zavaleta said. "But an endoscope is literally just a
flashlight on the end of a stick, so it will only give information
about the structure of the colon - you can see a polyp and know you
need to take a biopsy." "But if we could provide imaging tools to help
doctors see whether that particular polyp is cancerous or just benign,
maybe they don't even need to take it," she said.



========================================================================== Illuminated nanoparticles move through a blood vessel to find cancer. The coloring dyes were incorporated into nanoparticles to allow for more
sensitive imaging contrast when identifying cancerous cells.

To achieve this, the team has discovered a unique source of optical
contrasting agents from the household coloring dyes and pigments
that we routinely encounter. These "optical inks" can be attached
to cancer-targeting nanoparticles to improve cancer detection and
localization.

The dyes and pigments were discovered from common coloring agents that
already have U.S. Food and Drug Administration (FDA) approval, which the
team hopes may enable them to be more easily and safely implemented in
imaging practice.

For Zavaleta, inspiration struck in an unusual place -- an animation
class with Pixar artists in Emeryville, California, the home of the
famed studio.

Zavaleta, who enjoys art and animation among her hobbies, said she was intrigued by the inks and paints that the artists brought to class.

"I was thinking about how these really high pigment paints, like
gouache watercolors, were bright in a way I hadn't seen before, and I
was wondering if they had interesting optical properties," Zavaleta said.



==========================================================================
The idea led her to tattoo artist in nearby San Francisco, Adam Sky,
another artisan working with bright dyes.

"I remember I brought a 96-well plate and he squirted tattoo ink into
each of the wells," Zavaleta said. "Then I took the inks to our Raman
scanner (used to sensitively detect our tumor-targeting nanoparticles)
and discovered these really amazing spectral fingerprints that we
could use to barcode our nanoparticles. It was super cool." One of
the safety challenges of imaging using nanoparticles, is that often
these nanoparticles can have a prolonged retention in organs like the
liver and the spleen, which are responsible for trying to break down
the nanoparticle.

Because of these safety concerns, it's crucial to consider biodegradable nanomaterials. Currently, there are a limited amount of optical contrast
agents approved for clinical use.

With this in mind, Zavaleta's team considered common food dyes that
could be used to decorate the nanoparticles, such as the dyes found in
colorful candies like Skittles and M&Ms. These brightly colored food
products that humans routinely consume have been deemed by the FDA as
safe for human consumption.

"We thought, let's look at some of the FDA-approved drug, cosmetic and
food dyes that exist and see what optical properties are amongst those
dyes," Zavaleta said. "And so that's where we ended up finding that many
of these FDA- approved dyes have interesting optical properties that we
could exploit for imaging." The team has developed a nanoparticle that
will carry these highly pigmented imaging agents as a "payload." Zavaleta
said the particles are of a specific size that enables them to passively penetrate into tumor areas, but can also be retained due to their size.

Most of the imaging contrast agents used in the clinic today are small
molecule dyes.

"With small molecules, you may be able to see them accumulate in tumor
areas initially, but you'd have to be quick before they end up leaving
the tumor area to be excreted," Zavaleta said. "Our nanoparticles happen
to be small enough to seep through, but at the same time big enough to be retained in the tumor, and that's what we call the enhanced permeability
and retention effect." The nanoparticle can also be "decorated" with a
larger payload of the dye than previous small molecule imaging agents,
which the team has shown under fluorescence imaging leads to brighter
signal and significant localization of the nanoparticles in tumors.

"If you encapsulate a bunch of dyes in a nanoparticle, you're going to
be able to see it better because it is going to be brighter," Zavaleta
said. "It's like using a packet of dyes rather than just one single dye."
The research was co-authored by Helen Salinas, Dominie Miyasato, Olga
Eremina, Rodolfo Perez, Karen Gonzalez, Alexander Czaja, Sean Burkitt,
Arjun Aron, Augusta Fernando, Lauro Ojeda, Kimberly Larson, Ahmed Mohamed
and Jos Campbell from USC Viterbi Department of Biomedical Engineering.

Video: https://www.youtube.com/watch?v=dP6kg60RMck&feature=emb_logo

========================================================================== Story Source: Materials provided by
University_of_Southern_California. Original written by Greta
Harrison. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Helen R. Salinas, Dominie L. Miyasato, Olga E. Eremina, Rodolfo
Perez,
Karen L. Gonzalez, Alexander T. Czaja, Sean Burkitt, Arjun Aron,
Augusta Fernando, Lauro S. Ojeda, Kimberly N. Larson, Ahmed
W. Mohamed, Jos L.

Campbell, Beth A. Goins, Cristina Zavaleta. A colorful approach
towards developing new nano-based imaging contrast agents for
improved cancer detection. Biomaterials Science, 2020; DOI:
10.1039/D0BM01099E ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200902114453.htm

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