Analysis of tattoo inks reveals pigments used in textiles and paints and microparticles capable of damaging cells

Exhibition 'Tattoo, art under the skin', the largest exhibition on the history of this practice, held last year at Caixa Forum.JUAN BARBOSA

Tattooing is an ancient practice.

Ötzi's mummy, the remains of the man found in 1991 in the Ötz Valley (Austria) 5,300 years after his murder by blows and arrows, had 61 skin perforations filled with charcoal ashes, according to the investigation of the director of the Institute for Mummies and the Iceman, Albert Zink, published in

.

The ornamental, sentimental, ritual, identity or superstitious decoration of the skin has experienced a boom (between 9% and 30%, depending on the country).

But, although the health authorities monitor the composition of these substitutes for ancestral charcoal, some of their components escape conventional analysis.

A team of researchers at Binghamton, the State University of New York, has analyzed a hundred common tattoo inks and found ingredients that are not listed on the labels and potentially harmful particles.

The work, the results of which were presented Wednesday at the fall meeting of the American Chemical Society, started off in a different direction.

According to lead researcher John Swierk, the team intended to study the effects of lasers for tattoo removal.

“But then I realized that very little is actually known about the composition of tattoo inks, so we started looking at the most commonly used brands,” he explains.

Tattoo inks contain a pigment and a carrier solution.

The former may be a molecular compound, such as a blue pigment;

a solid compound, such as titanium dioxide, which is white;

or a combination of the two types of compounds, such as light blue ink.

The carrier solution transports the pigment to the middle layer of the skin and generally helps make the pigment more soluble.

You can also control the viscosity of the ink solution and sometimes include an anti-inflammatory ingredient.

More information

Tattoos, from stigma to sign of identity

But this is the general description.

Technology has been key to revealing the molecular composition of the smallest pigment particles.

Raman spectroscopy techniques (which uses the interaction of light with the chemical bonds of a substance to determine its structure), nuclear magnetic resonance and electron microscopy have made it possible to detect ingredients that were not listed on labels, such as ethanol.

"Every time we looked at an ink, we found something that made me stop and think," explains Swierk, who warns that none of the tattoo artists who have collaborated in the investigation knew the composition of the products they use.

The analyzes found azoic pigments in 23 brands of ink, used for coloring textile and leather articles.

According to the researcher, "no tattoo product establishment makes specific products, but it is the large companies that manufacture pigments for everything, such as paints and textiles, and they are the ones that use tattoo inks."

Azo pigments do not pose a health problem as long as they remain chemically intact, but the Joint Research Center (JRC), a scientific advisory body to the European Commission, warns that "bacteria or ultraviolet light they can degrade them into other nitrogen-based compounds which is a potential carcinogen.”

According to the European report

,

Azo pigments, in some cases, can release aromatic amines, which are linked to the appearance of some types of cancer, such as bladder cancer, and are intended for use in the rubber, aluminum and textile industries .

The concentration of these pigments is limited in the latest regulation.

The New York University team has also identified particles smaller than 100 nanometers (nm) in eight inks, thanks to electron microscopy.

A nm is one millionth of a millimeter and, according to Swierk, the range found is "worrying" because, as he clarifies, "particles of this size [less than 100 nm] can cross the cell membrane and potentially cause damage" .

EN ESPAÑOL

Analysis of tattoo inks reveals potentially damaging pigments and microparticles

The Binghamton researchers do not consider the investigation closed and will continue to reveal the composition of the tattoo inks.

The results will be incorporated into the

(What's in my ink?) so that, according to Swierk, "consumers and tattoo artists make informed decisions and know if the information they provide is accurate."

This website details that some pigments may include low levels of cadmium, mercury and lead or, on the contrary, concentrations of chromium greater than one particle per million, the maximum recommended to avoid allergic reactions.

The FDA, acronym for the US authority on food and drugs, warns of the possible adverse effects of a tattoo: infection, scars (both in the performance of perforations and in the removal of the drawing), allergic reactions, granulomas (nodules around the pigment that the body perceives as foreign) and some minor complications during MRIs.

Spanish regulation

In Spain, inks for tattoos and permanent makeup are regulated as personal care products, the marketing of which requires prior authorization from the Spanish Agency for Medicines and Health Products (AEMPS), which reviews the technical information, stability, sterility, information analytical and toxicological information.

The subsequent regulation, approved just over a year and a half ago, restricts the use of more than 4,000 hazardous chemicals and incorporates maximum concentration limits for substances such as azo dyes found in the Binghamton investigation, carcinogenic aromatic amines, polycyclic aromatic hydrocarbons ( PAH), metals and methanol.

This regulation is common in Europe and has been applied since January 4, except for some blue and green pigments, which will be subject to regulation from 2023 or will be withdrawn if they do not comply.

Labels for inks used in Europe must include ingredients and safety statements.

The AEMPS periodically updates the list of authorized products for permanent makeup (micropigmentation) and tattoos.

The consumer organization Facua also warns that the tattooist must have a degree and inform the user, "both orally and in writing", of the complications that may appear.

In Germany they go beyond common European legislation and the Federal Institute for Risk Assessment (BFR), an independent scientific body that advises the Government on the safety of food and chemical products, has called since last June for the participation of experts at the highest level to form a specific commission to assess the potential dangers associated with tattoos.

According to the president of the BFR, Andreas Hensel, "despite progress in identifying health risks, areas such as the long-term effects of pigments in the body still require research."

therapeutic tattoos

However, tattoos also have a positive side related to therapeutic uses.

Cristina Zabaleta, from the University of Southern California, uses ink to improve cancer diagnosis.

The author of a research published in

uses dyes incorporated into nanoparticles that provide a more effective image contrast in the identification of tumor cells.

“For example, if it is colon cancer, it is detected with an endoscope, but this is literally a flashlight on the end of a stick, so it will only give information about the structure of the colon.

You may see a polyp and know you need to take a biopsy.

But certain imaging tools can help doctors see if that particular polyp is cancerous or just benign,” he explains.

Also the tattoo technique has other applications.

A team from the University of Missouri has investigated how to create bioelectronic devices on the skin using pencils that are 93% graphite.

“The conventional approach to developing a biomedical electronic device on the skin is often complex and often expensive to produce.

Our approach is low cost and very simple.

We can make a similar device using available pencils and paper,” says Zheng Yan, a professor of engineering at the center.

Francesco Greco of the Graz University of Technology has developed "tattoo electrodes," conductive polymers made from standard tattoo ink that stick to the skin to measure heart or muscle activity.

“Tattoo electrodes can record electrocardiographic (EGG) signals with the highest quality because brain waves are in the low-frequency range and EEG signals have very low amplitude.

They are much more difficult to capture in high quality”, explains Laura Ferrari, who worked on this project.

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