Scientists are investigating the chemical composition of tattoo ink amid growing safety concerns

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

According to lead researcher John Swirk, a Binghamton chemist, the project originally began when his group became interested in tattoos as a medical diagnostic tool. This led to an interest in laser tattoo removal, specifically how laser light makes tattoos disappear. “We realized that we didn’t understand much about the interaction between light and tattoos,” Swirk said during a press briefing at the ACS meeting. “My group studies how light can cause chemical reactions, so it was natural.”

This meant learning more about the chemistry of tattoo ink, which is also poorly understood. One reason for this significant gap in scientific understanding is that in the US, at least, tattoo ink manufacturers are not required to disclose ingredients, and even if they do, there is no real control over whether that disclosure is correct. . Spruce.

Conventional tattoo ink contains one or more pigments (which give the ink its color) in a “carrier packet” to help deliver the pigments to the skin. The pigments are the same as in paints and textiles. These can be small pieces of solids or individual molecules such as titanium dioxide or iron oxide (for white or rust-brown colors, respectively). When it comes to carrier bags, most ink manufacturers use grains or alcohol, sometimes adding a bit of witch hazel to the mix to help the skin recover from the tattooing process. There may also be other additives to adjust the viscosity and keep the pigment particles in suspension in the package.

First, the team surveyed several tattoo artists and found that while artists had favorite brands, they knew very little about the chemistry of their favorite inks. Next, Svirko’s lab used a variety of techniques to analyze a wide range of commonly used tattoo inks, including Raman spectroscopy, nuclear magnetic resonance spectroscopy, and electron microscopy. This allowed them to identify specific pigments and other ingredients in different inks.

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

What’s more, Swirk says, “often the particles used in tattoo ink are very small—less than 100 nanometers in diameter. When you get to that size regime, you start to worry about nanoparticles entering cells, going into the nucleus and causing damage, possibly causing cancer.” About half of the 18 inks analyzed by electron microscopy had particles in this alarming size range.

The European Commission recently began cracking down on harmful chemicals in tattoo inks, including two widely used blue and green pigments (Pigment Blue 15 and Pigment Green 7), saying they are often of low purity and may contain hazardous substances. “Anyone getting a tattoo in the US with blue or green tattoo ink should assume that these pigments of concern will be included,” Sverk said. “Most tattoo manufacturers are discontinuing the sale of blue and green ink in Europe [in response to the regulatory crackdown]it is not necessary to change the pigments, because at the moment there is no obvious replacement.’

However, he added that while the EU’s scientific evidence is concerning, it is not yet conclusive on the overall safety of pigments. “These particular pigments have been used for tattooing for a very long time,” Swirk said. “As with all things tattooing, consumers should decide on their specific comfort level and then act accordingly.”

That’s why Sverk and his team created a new website, What’s in my ink? Their study will ultimately be the first comprehensive study of tattoo ink in the US market, according to Sverk. Currently, the site only has rudimentary data from previous peer-reviewed studies, but once his team completes an analysis of commercial tattoo inks and the resulting data goes through a peer review process, the site will become a valuable consumer resource for tattoo ink composition information.