Caterpillars Spin 'Tougher Than Steel' Silk

Recreating spider silk, the flexible yet tough as steel strands of protein, spun by the arachnids, has been the holy grail for material scientists for many years now. However, making it in bulk has been a little elusive, thanks to the fact that spiders are very territorial and devour each other if placed in very close quarters.

To bypass this issue, researchers have in the past used engineered cells and even goats, to replicate spider silk proteins. But, while they could produce the protein, to spin it into usable silken threads proved to be a little challenging and not very practical for mass production.

To get around the issue, researchers from the University of Wyoming began with an animal that already spins silk - Silkworms. While the fluffy large cocoons they create have been harvested and woven into cloth for centuries, the silk produced is not as strong as that created by spiders. In order to alter that, the scientists injected a synthetic spider silk gene into the cocoons. This gene contained amongst other things, the code for spider silk elasticity and strength.

To their delight, the experiment worked like a charm. The resulting silk, that comprised of 95% silkworm protein and 5% spider silk proteins is 48% stronger than normal silk and about 61% as strong as the overall strength of dragline spider silk - the strongest silk spun by spiders. The best part is, that they believe the silk can be mass produced, which means the we may be able to use it to make stronger artificial limbs, tendons, parachutes and even, bullet-proof vests.

While the material created is stronger than steel, the team is not satisfied. They are now working on injecting more spider DNA, so that the resulting material can be at least as strong, if not stronger than the one created by spiders.

Resources: csmonitor.com, nationalgeographic.com