Female black widow spider (Latrodectus hesperus) walking on web made of dragline silk. Image credit: Mark Chappell, UCR.

There are currently no products on the market based on the dragline silk of spiders. “There’s nothing quite as good yet as natural dragline silk, but we should get a lot closer now that we have the full genetic recipe,” said Cheryl Hayashi, Associate Professor of Biology at the University of California, Riverside (UCR).

With the ingredients and their genetic blueprint now known, it may be possible to synthetically produce the proteins by inserting the genetic sequences into host organisms such as bacteria, plants or animals, she said. Once the pure proteins are harvested, a manufacturing challenge will be spinning them into silk fibres that have the same remarkable properties as spider spun silk. But several advances have recently been made in artificial spinning methods.

When spiders manufacture dragline silk, their silk glands produce a “gooey” slurry of the proteins needed, which are transported to the spinneret through a duct where the proteins interact and align to form the silk strands.

“The production of artificial silk is not quite there yet,” Hayashi said. “Now, with the full length genes known and as we learn more about theses two proteins, hopefully we will have a better shot at mimicking nature.”

Spider silks have some of the best mechanical properties of any known natural fibres, thus they are being considered in the improvement of a variety of products including surgical microsutures and specialty ropes. Dragline silk – just one type of the seven different silks that an individual spider produces – are used by spiders as the structural foundation of their webs and to support their body weight as they move about. The dragline silk of black widows is one of the strongest and toughest spider silks identified thus far.

Hayashi’s laboratory utilised specialised instrumentation in the Core Instrumentation Facility of the UCR Institute for Integrative Genome Biology in their quest to identify the genes that encode the proteins MaSp1 and MaSp2, then to determine the full genetic sequences.

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