Spider silk—six times tougher than Kevlar and stronger than steel—has now been produced by an unexpected source. Spider silk is a biological protein fiber spun by spiders. Many of these fibers have exceptional properties, including high tensile strength, extensibility and toughness, being able to absorb large amounts of energy relative to its thickness before breaking. While silkworms also spin silk, their silk is less mechanically impressive, but much easier to harvest. Using genetic modification, scientists at China's Donghua University have figured out how to use silkworms to produce spider silk, according to a new study in the journal Matter. Silk...