Researchers at the University of Colorado Boulder have developed a novel type of temporary tattoo that can be made invisible or visible depending on the lighting conditions. These tattoos, created using a material called PhotoTat, become visible under ultraviolet (UV) light but fade over several hours and can be turned off more rapidly when exposed to bright LED light.

The ink used in these tattoos consists of dyes embedded in nanoparticles of a plexiglass-like polymer, a substance commonly utilized in medical implants and dermal fillers. This technology allows the tattoos to be revealed or concealed at will, depending on the environment and lighting.

According to Prof. Carson Bruns, the study’s lead author, the switching capability of the tattoos offers practical benefits. For example, during everyday social situations where individuals might prefer to hide their body art, such as family gatherings, the tattoos can remain unseen. Conversely, they can be made visible in settings where temporary identification or medical markings are needed.

One potential application highlighted by the researchers is in the field of oncology. Cancer patients often receive small tattoos to guide radiation therapy precisely. The ability to switch these markings on and off could improve patient comfort and reduce social stigma associated with permanent tattoos.

The research team emphasizes the innovative nature of this technology, which combines materials science with biomedical applications to create a versatile, reversible body marking system. Further studies and developments are expected to explore other potential uses and to refine the durability and responsiveness of the tattoos under different lighting conditions.