"When someone wants to get a tattoo, they are often very careful in choosing a parlour where they use sterile needles that haven´t been used previously.
"No one checks the chemical composition of the colours, but our study shows that maybe they should", said Hiram Castillo, one of the authors of the study and scientist at the ESRF.
There are few studies which have looked at the toxic impact of tattoo ink, which can contain preservatives and contaminants like nickel, chromium, manganese or cobalt.
"We already knew that pigments from tattoos would travel to the lymph nodes because of visual evidence: the lymph nodes become tinted with the colour of the tattoo," said Bernhard Hesse, one of the two first authors of the study and ESRF visiting scientist.
"It is the response of the body to clean the site of entrance of the tattoo. What we didn't know is that they do it in a nano form, which implies that they may not have the same behaviour as the particles at a micro level. And that is the problem: we don't know how nanoparticles react."
The new case study was published in the journal Annals of Internal Medicine.