“The procedure has not yet been tested on humans and researchers will need to show it is safe to use, particularly if the dye is injected beneath the skin.”
Stanford researchers smeared tartrazine, the yellow dye in US Doritos and SunnyD, on a mouse’s belly and saw its liver, intestines and bladder through the skin. It only clears tissue in red light, and only as deep as the dye soaks in. Going deeper means microneedles or injections. The pitch to doctors is skipping biopsies, and nobody has tried it on a human yet.