Tattooing, whether decorative or ritual, is widespread in all human societies, yet the inks used and their impact on the organism has so far been little studied. A study published in Scientific Reports by a team of German researchers, associated with the European Synchrotron in Grenoble, shows that the nanoparticles contained in the inks travel in the organism and settle there permanently.
The tattoo ink is composed of organic pigments – which exists or not in the state in nature – different according to the colors. For example, carbon black – organic – for black, or titanium dioxide – inorganic – for white. These pigments are also associated with toxic additives such as bromine, aluminum, chromium or cobalt.
These elements are composed of particles of different sizes, from the microparticle of one millionth of a meter to the nanoparticle, 1000 times smaller.
The needle in action
During the tattoo, the needle that injects the ink passes through the epidermis to the second layer of the skin, the dermis, to fix the drawing. The ink components can then diffuse directly into the body through the bloodstream, but also, indirectly, through the immune system that protects the body. It reacts to the aggression of the ink and sends cells to capture the aggressor – the particle – which is then transported to the lymph nodes. The lymph nodes, numbering 800, distributed throughout the body, will retain these particles.
Particles in the light of science
Until now, it has already been found that white tattoos, in particular, whose ink contains titanium dioxide, cause irritations more often than others. It is also known that the larger particles that make up the inks diffuse beyond the skin. But scientists have now turned their attention to nanoparticles, which have so far been ignored. They compared the composition of the lymph nodes of deceased tattooed persons with the pigments present in their tattoos.
For this, they used ultra-powerful X-rays and a particle accelerator, the European Synchrotron, located in Grenoble, France.
The study shows that nanoparticles of several elements, more or less toxic, are present in the lymph nodes. The researchers found in particular the green and blue organic pigments, but also titanium, resulting from the titanium dioxide.
Titanium dioxide is frequently used as a bleaching agent, particularly in chewing gums and sun creams, but it has recently been shown that nanoparticles of titanium dioxide, toxic, classified as ” potentially carcinogenic to humans ” by the Center international cancer research, cross the cell walls.
Unknown long-term effects
The problem is that if we do not yet know all the long-term effects of nanoparticles on the organism, there is no doubt about the toxicity of some of them. For researchers, the next step will be to link the adverse effects to the chemical properties of the inks.