Spider silk is flexible, biodegradable and one of the strongest substances on earth. In the spider’s storage gland, the silk protein is liquid; as it passes out of the abdominal canal, it becomes a gossamer thread that can hold the spider’s weight and its unsuspecting prey. What forms the threads from the liquid? Researchers at the Swedish University of Agricultural Sciences (SLU), Stockholm, Sweden, have discovered one possible answer: Along the canal, conditions change from a neutral pH of 7 to a slightly more acidic pH of 6. At the more acidic pH, threads form rapidly and in an orderly way. Artificial spider silk’s flexibility and strength could make it suitable for everything from surgical sutures to bulletproof vests. Read more about it in the scientific journal Nature, May 13, 2010.