Tattoos mark the spot - for surgery - then disappear

Tattoos aren't just for body art. They can have medical applications, too. Doctors are using them on patients to mark an area for future treatment — particularly for non-melanoma skin cancer such as basal cell carcinoma — but the inks can cause problems. Now scientists have developed a better solution. In the journal ACS Nano, they report a new ink that glows only under certain light conditions and can disappear altogether after a period of time.