Cobwebs are remarkably strong structures. Sure, a sweep will get them out of your lane, but consider how bigger you are than the web and yet you often still feel a bit of resistance. And of course for insects preyed upon by a spider, a web becomes a deadly trap, from which it is impossible to get out. Researchers have been studying spider webs to understand what makes them so strong and to learn from spiders how we can possibly make similar materials.
Earlier this year, researchers at William & Mary discovered new details about the protein structures of silk fibers. Such information can then help other researchers create new structures that could be as strong as spider silk.
Over the past few decades, several research groups have produced and tested materials inspired by cobwebs. One way to do this is to create spider silk replicas made from spidroins, the proteins that make up spider silk and are the core building blocks of spider webs. Spiders can produce spidroins, but it’s not quite possible to employ a factory full of spiders and have them create spidroins on demand. People have certainly thought about it, but it takes a long time and according to a recent study, another problem 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, spidroins are encoded by genes, so if you know the genetic code, it is possible to produce recombinant spidroins in other organisms. This is the main method used by researchers to produce spider silk without spiders. It also makes it possible to modify spidroin so that it has the desired properties of being able to form strong fibers, but to adjust it for purposes other than “making a cobweb.”
Scientists have achieved this in the past by expressing the protein in goat’s milk. The now defunct Nexia company produced a fiber called BioSteel in this way, but was unable to scale it up to commercial proportions. Yet 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 the spidroin proteins in microorganisms such as bacteria. Several research groups and companies have embarked on this path. This is also the production process used by Japanese biotech company Spiber, which produces Brewed Protein, a proprietary fiber they have used to create substitutes for different types of fabrics. Their materials were featured on the Paris Fashion Week 2020 catwalk in a collection by Yuima Nakazato.
Apparel textiles aren’t the only materials that could be made from recombinant spider silk fibers. Other researchers focus on using them to develop medical applications, biosensors, tissue engineering, security equipment, smart technologies, industrial applications and more.
There’s a lot of potential for cobwebs beyond Halloween decorations!