 Silkworms have been used to create silk fibers for centuries, but now researchers are using them to create a new type of material that can generate and release reactive oxygen species, ROS, when exposed to light. This new material, called MK2 silk, has the potential to replace dangerous foreign semiconductor nanoparticles with a safer alternative. This article was authored by Yung Wulim, Jung Woo Park, Song Won Kim, and others.