Researcher Carson Bruns has a tattoo he can turn on and off with light. He can also use light to doodle on himself Tattoos could be radically reimagined following the development of inks that can be turned on and off by exposing them to light. This could be used medically – or to hide the butterfly on your ankle from a judgemental relative.
They call the new technology, which has been tested on silicon, “PhotoTat”. There is little mechanical difference between a traditional tattoo and the new inks, says Bruns. Both are pigment particles implanted in the dermis with a needle, he says.
They also both stay there permanently and are applied with the same machines and methods. The difference is the pigment, says Bruns. With PhotoTat, “ultraviolet light writes the colour in, bright visible light erases it, and the cycle can be repeated”, he says.
The light-sensitive tattoos can currently be made from 16 colours, which are clearly distinguishable from each other. From these colours, there are at least 300 different shades. White is unavailable because it reflects light, rather than absorbing it, so can’t be switched on and off like other colours.
The researchers have also been unable to develop a true cyan. Another issue is that the blue ink gradually develops a permanent, purplish colour as the dye slowly photo-degrades over many on/off cycles. Someone with one of these tattoos would also need to apply sunscreen to prevent the colour activating when they are exposed to sunlight.
In terms of safety, Bruns says the polymer that encapsulates the dyes is non-toxic and has a long history of use in permanent biomedical implants. Still, extensive safety studies need to be carried out before the tattoos will be available to the public. Signe Bedsted Clemmensen at the University of Southern Denmark says tattoo ink in the body is a foreign substance, which has been linked to cancer, regardless of whether it is visible or invisible.
Extract — continue reading at the source.
