Silkworms spin a colorful yarn

Chemists in India have cut a step in the silk-dyeing process by developing an eco-friendly method that allows silkworms to spin fluorescent, colored silk: they feed the worms dyed mulberry leaves. The worms have been spinning white fibers since silk was first processed some 5,000 years ago in China; conventional coloring processes produces potentially harmful wastewater, so scientists have been seeking a “greener” dyeing method. A team from the National Chemical Laboratory in Pune, India, had been working on a single-dye method that proved to be expensive, so they turned to less-costly azo dyes. (Many colored textile and leather articles are treated with azo dyes and pigments.) They dipped or sprayed mulberry leaves with seven dyes, of which three were incorporated into the silk, and none affected the worms’ growth.