Humans have been using the same tattooing technologies for thousands of years. It's time for an upgrade. The Laboratory for Emergent Nanomaterials is re-thinking the tattoo pigment as a way to permanently embed new technologies in the skin. These researchers have been formulating tattoo inks that conduct electricity and change color in response to different stimuli. These "tech tattoos" could power biomedical devices and wearable technologies, monitor and diagnose health issues, and augment human sensing and self-expression.
In this project, the researchers developed a tattoo ink made of photochromic microcapsules; a few seconds of tattooing this ink into skin leaves a color-changing mark that is activated by UV light. These tattoos turn blue in sunshine (or another source of UV light) but disappear when sunscreen is applied, or in indoor lighting. This intradermal tattoo lasts for up to six months and offers a new way to monitor UV exposure for skin cancer prevention.