Health and Medicinemedicine

Doctors Have A Good Reason For Tattooing People's Colons


Rachael Funnell

Social Editor and Staff Writer

clockMar 22 2022, 14:57 UTC
colon tattooing

And the "ink" just got better. Image credit: Juan Gaetner /

The colon might not spring to mind when considering placements for your next ink, but endoscopic tattooing (as it’s more professionally known) is actually a very useful technique for tracking lesions for monitoring and resection. Now, colon tattooing just got better thanks to a new biomaterial-based ink that carries fewer side effects and is more efficient than preexisting formulations.


The new colon tattoo ink was presented at the spring meeting of the American Chemical Society (ACS) 2022, following promising results for the novel ink’s usage in porcine intestines and living mice. The researchers behind its formula were hoping to improve the ink’s spot localization, as older inks had problems with leaking beyond the lesion of interest.

“Many times, these [lesions] are very flat, very subtle lesions, and there’s a need to mark them so that the specialist going in later can find them,” said gastroenterologist Dr Rahul Pannala, associate professor of medicine at the Mayo Clinic Arizona, in a statement.

Most colon tattoos are done in carbon black giving them high contrast to the surrounding intestinal tissue, but they can rapidly diffuse making it harder for surgical specialists to identify the lesion. This diffusion is also thought to contribute to the association of peritonitis and abscess formation, two common side effects that come with existing inks.

To overcome these risks and shortfalls, researchers on the new paper used metal-derived nanoparticles which would be easy to spot under the light conditions of a colonoscopy (where insects are sometimes discovered). It’s also possible they could be visible in X-ray computed tomography (CT) imaging carried out before surgery, though more research is needed to confirm this.

colon tattoo

A commercial ink (left) diffuses far from injection sites (arrows) under mouse skin, but the new colon tattoo ink (right) diffuses much less. Image credit: Dr Jordan Yaron

“Because the nanoparticles have X-ray CT contrast properties, as well as being visible under endoscopic light, we think the new inks could allow multi-modal imaging,” said principal investigator Dr Kaushal Rege from Arizona State University in a statement.

By combining the nanoparticles with sticky polymers that would adhere to the colon’s submucosa, the new approach also reduces the risk of diffusion of the ink muddying the surgical field. More precision could see an improvement in colorectal surgery outcomes by making it easier to identify and remove complex polyps and tumors.

The announcement of the novel ink technology comes during Colorectal Cancer Awareness Month. Hosted by the Colorectal Cancer Alliance, it aims to encourage awareness and to improve screening and management of cancerous and pre-cancerous conditions.


So far the novel ink has been tested on porcine intestinal tissue and living mice, but the researchers hope their progress can contribute towards these goals in humans, and perhaps even improve patient care across a wider range of conditions.

“[The novel ink] could lead to safer removal of complex polyps and tumors, and to better identification in imaging scans, and it’s not limited to just colon cancer,” said Pannala. “If we’re able to develop an ink that is very precise, we could also use it to mark growths and tumors anywhere in the gut, or even in the pancreas.”

Health and Medicinemedicine
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