An improved ink for colon tattoos (IMAGE) American Chemical Society Caption A commercial ink (left) diffuses far from injection sites (arrows) under mouse skin, but a new colon tattoo ink (right) diffuses much less. Credit Jordan Yaron, Ph.D. Usage Restrictions Image may only be used with credit shown. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.