Spider webs are extremely strong structures. Sure, a flick of a broom will get them out of your driveway, but think about how much bigger you are than the web and yet you often still feel a bit of resistance. And of course for a spider’s insect prey, the web becomes a deadly trap from which it is impossible to get out. Researchers have studied spider webs to understand what makes them so strong and to learn from spiders how we might be able to make similar materials.
Earlier this year, William & Mary researchers discovered new details about the protein structures in silk fibers. Such information can then help other researchers create new structures that may be as strong as spider silk.
In recent decades, several research groups have been producing and testing materials inspired by spider webs. One of the ways to do this is by making copies of spider silk based on spindroins, the proteins that make up spider silk and are the central building blocks of spider webs. Spiders can produce spidroins, but it’s not exactly feasible to employ a factory full of spiders and have them create spidroins on demand. People have certainly thought about it, but it’s very time-consuming, and according to a recent review, another issue is that spiders show “cannibalistic behavior.” They would eat each other if bred to increase spider silk production!
So how else can you make spidroins? Like other proteins, spindroins are encoded by genes, so if you know the genetic code, it is possible to produce recombinant spindroins in other organisms. This was the main method researchers used to produce spider silk without spiders. It also makes it possible to alter spidroin so that it has the desired properties of being able to form strong fibers, but adapt it for purposes other than “spider web making”.
One way scientists have done this in the past is by expressing the protein in goat milk. The now-defunct company Nexia produced a fiber called BioSteel this way, but was unable to scale it to commercial proportions. However, BioSteel itself was functional, and in 2012 artist Sruli Recht used it to create a shirt, which shows how recombinant spider silk could be used in textiles.
Another way to produce spider silk without spiders is to express spidroin proteins in microorganisms such as bacteria. Several research groups and companies have followed this path. It’s also the production process used by Japanese biotech company Spiber, which produces Brewed Protein, a proprietary fiber it has used to create replacements for different types of fabrics. Their materials have been presented on the catwalk of Paris Fashion Week 2020 in a collection by Yuima Nakazato.
Clothing fabrics aren’t the only materials that could be made from recombinant spider silk fibers. Other researchers are focusing on using them to develop medical applications, biosensors, tissue engineering, security equipment, smart technology, industrial applications and more.
There are many possibilities for spider webs beyond Halloween decoration!