- Spider silk is so strong it could be used to manufacture human biomedical implants. But it cannot be artificially produced.
- Spiders create silk by converting a protein feedstock (dope) from a gel into a solid inside their bodies. While researchers know some of the ingredients for the gel and the structure of the glands the spider uses to spin its silk, they do not know enough to replicate the process artificially.
- Researchers at Oxford University are working with ISIS scientists to examine what happens during the spinning process where they can ‘photograph’ the material’s molecular structure as it changes.
ISIS is being used to identify how silk is spun by spiders in order to harness its strength and elasticity for everything from new plastics to biomedical implants. Spider-silk is five times the strength of steel and absorbs three times more energy than the material used in bullet proof vests. Unlocking the mystery behind the strength of spiders’ silk could help scientists develop new products with unprecedented strength.
Spiders spin silk from a liquid feedstock called dope – a mix of water and proteins. This is stored as a gel in specialised silk glands inside their bodies. When the dope is pulled through their spinning glands it becomes a very resilient solid that could have many potential uses in the industrial world. But whilst researchers know the structure of the silk glands, and some of the ingredients for dope, they do not yet have nature’s exact recipe and instructions for replicating the final product – an extremely strong silk fibre.
A research team from Oxford University is using the neutron beams at the ISIS neutron source to ‘photograph’ silk at the atomic scale as it transforms from a gel into a solid fibre. ISIS can show them how the structure of the dope transforms during the process – specifically how the proteins in the gel-like dope change position and shape to become a strong and resilient length of fibre. Experiments at ISIS have already unlocked some of the answers. But the new Second Target Station at ISIS, which opened in 2008, will take the team even closer to the answer. It is designed so that certain beam lines are perfectly tuned for studying biological materials. This will help the team to get a highly detailed view of the material and allow them to watch how individual molecules change as the dope becomes a fibre. This is the first example of ISIS being used to combine research in biology, physics, rheology, and polymer chemistry to answer some of nature’s most challenging questions.
“This is an excellent technique for understanding the spider’s magic tricks,’ explains Dr Chris Holland, a research fellow at Oxford University’s Silk Group. “We are asking how nature makes such amazing materials. By fully understanding this fundamental process, hopefully we can then control it, and apply it to a host of new substances with the potential to deliver super strong and flexible materials for the future.”
Research date: January 2008