Scientists explore chemistry of tattoo inks amid growing safety concerns

Scientists at Binghamton University (State University of New York) have analyzed nearly 100 different tattoo inks and found that manufacturers’ ingredient labels (when used) are often inaccurate and that many inks contain tiny particles at the nanoscale. which can be harmful to human cells. , They presented their findings at this week’s meeting of the American Chemical Society (ACS) in Chicago.

According to principal investigator John Swierk, a Binghamton chemist, the project initially began when his group became interested in tattoos as a tool for medical diagnosis. This moved into interest in tattoo laser removal, specifically how laser light causes tattoos to fade. “We realized we didn’t understand a lot about the interaction between lighting and tattoos,” Swierk said during a press briefing at the ACS meeting. “My group studies how light can drive chemical reactions, so it was a natural fit.”

This meant learning more about the chemical composition of tattoo ink, which is not well understood. One reason for this significant gap in scientific understanding is that in the US, manufacturers of tattoo inks are at least not required to disclose ingredients, and even when they do, there is no actual The inspection is not whether these disclosures are true, per se.

Typical tattoo inks contain one or more pigments (which give the ink its color) within a “carrier package” to help deliver the pigment to the skin. Pigments are the same ones that are used in paints and textiles. They can be either solid or small fragments of discrete molecules, such as titanium dioxide or iron oxide (for their white or rust-brown color, respectively). For carrier packages, most ink manufacturers use anise or rubbing alcohol, sometimes with a little bit of witch hazel added to the mixture to help the skin heal after the tattoo procedure. There may also be other additives to adjust viscosity and keep pigment particles suspended in the carrier package.

First, the team interviewed several tattoo artists and found that while the artists had their favorite brands, they knew very little about the chemical composition of their preferred ink. Subsequently, Swierk’s laboratory used a variety of methods to analyze a wide range of commonly used tattoo inks, including Raman spectroscopy, nuclear magnetic resonance spectroscopy and electron microscopy. This enabled them to identify specific pigments and other ingredients in various inks.

They found that many ingredients were not visible on manufacturers’ labels, such as an ink that contained ethanol, even though it was not listed on the label. And 23 inks analyzed so far show evidence of azo-containing dyes. Such pigments are usually inert, but exposure to bacteria or UV light can degrade them into a nitrogen-based compound that can potentially cause cancer.

In addition, Swier says, “the particle sizes often used in tattoo inks are much smaller—less than 100 nanometers in diameter. When you get down to that size regime, you’ll find nanoparticles penetrating into cells, into nuclei.” There seems to be concern about ingesting and doing damage, possibly causing cancer.” About half of the 18 inks analyzed by electron microscopy contained particles in this worrying size range.

The European Commission recently started cracking down on harmful chemicals in tattoo inks, which include two widely used blue and green pigments (pigment blue 15 and pigment green 7), claiming that they are often of low purity and may contain hazardous substances. “Anyone tattooing in the US with blue or green tattoo ink should assume that those pigments of concern will be included,” Swier said. “Most tattoo makers are discontinuing the sale of blue and green inks in Europe [in response to the regulatory crackdown]Not necessarily changing colors, as there is no clear replacement at this time.”

However, he added that with respect to EU scientific data, it does not yet have a definitive conclusion about the overall safety of the pigments. “Those special pigments have been used in tattooing for a very long time,” Swier said. “Like everything related to tattoos, it’s up to consumers to decide on their particular comfort level and then proceed accordingly.”

That’s why Swierk and his team created a new website, What’s in My Inc.? Their research would eventually constitute the first comprehensive survey of tattoo inks in the US market, per Swierk. Currently only primary data is available from prior peer-reviewed studies available on the site, but once his team completes their analysis of commercial tattoo inks and the resulting data have been passed through a peer review process, the site Will serve as a valuable consumer resource. Information about the composition of tattoo ink.