Red Fluorescent Silk Cocoons (IMAGE) Purdue University Caption When a green light shines on red fluorescent silk, a mechanism to kill pathogens is activated. Credit Purdue University image/Jung Woo Leem Usage Restrictions None 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.