BIOMATERIALS: Building a better tattoo

Researchers from Massachusetts General Hospital (MGH; Boston, MA) and Brown University (Providence, RI) have developed microencapsulated resorbable tattoo pigments designed specifically with laser removal in mind. In preclinical in vivo studies with rats, the biocompatible materials demonstrated “significant improvement” in skin tolerance and removal when compared to standard India inks used in most tattoos, according to Rox Anderson, professor of dermatology at Harvard Medical School and director of the Wellman Center for Photomedicine at MGH. Anderson presented preliminary results from the MGH and Brown study at the annual American Society for Laser Medicine and Surgery meeting in Boston in early April.

While the popularity of tattoos, or “permanent body art,” continues to grow, studies have shown that nearly 50% of people who get tattoos ultimately regret them and seek some form of removal. However, only half of tattoos can be removed significantly with a series of five to ten laser treatments. In addition, traditional tattoo inks—many made from toxic and carcinogenic materials such as heavy metals and azo dyes—pose various health risks when applied and when broken up via laser removal. The microencapsulated resorbable pigments developed by Anderson and colleagues comprise safe, biocompatible materials engineered to be removed by lasers “on demand.” The pigments are made from polymer materials already used in a number of clinical applications and bioresorbable colorants that are FDA-approved for use in cosmetics, foods, drugs, and medical devices.

In studies at MGH, pigment particles consisted of a bioresorbable dye encapsulated in a nondegradable protective microsphere (see figure). India ink and test-pigment tattoos were applied to 16 hairless rats using standard tattoo equipment; after four weeks, the tattoos were treated with a Q-switched Nd:YAG laser. Laser energy directed at either the dye itself or chromophores within the capsule ruptured the capsule, releasing the dye. Skin reaction was evaluated clinically and histologically following tattoo application and laser treatment.

Two months after treatment with the laser, intensity measurements showed a removal efficacy of 22% for India ink and 52% for the test pigments. In addition, while the microencapsulated inks behave in vivo similarly to conventional tattoo inks, histological and clinical evaluation following tattoo application and removal showed no adverse skin reactions, no allergic reactions, no infections, no inflammation, and no adverse systemic reactions.

“These are the first tattoo inks designed and engineered with safe, easy tattoo removal in mind,” Anderson said. Further development of the prototype inks is being handled by Freedom-2 (Philadelphia, PA), a startup established specifically to commercialize this technology.