A device that recreates the conditions in spiders' silk-spinning apparatus has produced 1,000 metres of material that is tougher than other spun artificial spider silks.

Credit: Lena Holm

Anna Rising and Jan Johansson at the Swedish University of Agricultural Sciences in Uppsala and their colleagues used the bacterium Escherichia coli to make a water-soluble protein containing domains from the silks of two species of spider, Euprosthenops australis and Araneus ventricosus. The team then pumped the protein solution through a glass capillary into an acidic bath, mimicking the conditions experienced by natural silk as it passes down through a spider's silk glands and silk ducts. The result was continuous fibres with a diameter of 10–20 micrometres.

The artificial silk (pictured) had some physical properties that were similar to those of natural silk, but was less tough.

Nature Chem. Biol. http://dx.doi.org/10.1038/nchembio.2269 (2017)