have spent three years working out how to integrate color into the core of silk filament, called the fibroin, so it doesn't wash away. this is the silkworm's normal feed, a thick green paste of mulberry powder and water, to which the researchers added a special chemical dye. then they fed it to the worms, the larvae of the silk moth, which changed color within several hours. the incorporation of dye molecules while the silk was being synthesized in the worm's silk glands ensured that the dye in the silk would combine at a molecular level when the silkworm began to spin its cocoon. >> in the future, it's hoped the silk used to make these scaffolds will have not just color incorporated into it, but properties that could fight bacteria, inflammation, and cancer. meaning that one of singapore's most fashionable exports could soon be life-saving silk. >> good-bye. >> see you in the new year. good-bye. >> today on "earth focus," everyday chemicals and how they may be harming us, coming up on "earth focus." [captioning made possible by kcet public television] they are everywhere in our environment.