Scientists at the University of Colorado Boulder have developed a new type of tattoo ink, named PhotoTat, that can be made invisible or visible on demand. This innovative ink is designed to be revealed only under UV light, allowing tattoos to be temporarily hidden when necessary, such as for job interviews or formal events.
The PhotoTat ink utilizes a plexiglass-like material, similar to that found in dermal fillers, combined with color-changing dyes. These dyes are initially invisible to the human eye and are encased in tiny spheres made of polymethyl methacrylate (PMMA). When exposed to UV light, the colors become apparent. Conversely, exposure to bright LED light can switch the colors off, rendering the tattoo invisible again. The visible colors typically last for a few hours.
Lead author Carson Bruns has personally tested the ink, sporting a black outline of fish scales on his leg filled with PhotoTat. When illuminated with a UV flashlight, the scales display red, orange, and blue hues.
Despite the promising development, the ink has not yet been approved for human use, and several challenges remain before it can be made available in tattoo parlors. Miriam O'Duill, an Associate Professor of Chemistry at the University of Nottingham, noted that direct sunlight could activate the tattoos if not protected by sunscreen, and indoor light might cause them to fade over several days. Additionally, the blue ink currently degrades after a limited number of activations, leaving a permanent mark. Rigorous toxicity and safety testing are required, which is expected to take several years.
In related news, a UK-based startup called CipherX has developed a painless tattoo system that uses a plaster-like patch with microneedles to deposit ink, creating permanent 'microdot' tattoos with minimal discomfort and damage to the skin.