For the next four years, Duffy worked with scientists and tattoo artists around the country to try and figure out if this could – and should – be done. "I just kept on asking myself the question, How can you really make a tattoo even more personal than it already is?" Duffy says. After numerous patents, Duffy landed on a system that turns the DNA of another human being or pet into a powder-like substance (called "Everence"), which can then be mixed into tattoo ink. As freaky as the concept sounds, it was actually closely monitored by Bruce Klitzman , associate professor of surgery at Duke University, and Edith Mathiowitz , professor of medical science and engineering at Brown University.