When we think of spiders, what do we usually think of? Webs! A sticky, dusty mess of webs always getting into corners. We don’t usually think of spider thread’s utility in the manufacture of clothing or band aids. But when we look into it, spider silks are an incredibly useful material that has extraordinary potential.
Why is spider silk such a useful material?
Spider silk is unique. Spiders actually produce seven different types of silks; the silk of most interest to scientists is called dragline silk. This is the silk used to create the framework of a spider’s web. Its strength lies in the hundreds of protein fibers stacked and linked together like building blocks. This structure gives dragline silk a toughness and elasticity that is one of a kind—stronger than Kevlar, more flexible than nylon, and with a thinner diameter than a strand of human hair.
Potential utilization of spider silks
What kind of potential applications does such a versatile material have? The properties of spider silk have the potential to revolutionize the medical and textile industries. The possibilities are numerous: bulletproof body armor, wear-resistant lightweight clothing, alloy for suspension bridges, biodegradable bottles, bandages, surgical thread, and more.
Some of the leading researchers in spider silks are most interested in its application for artificial ligaments, cell scaffolds for skin regeneration, and the connection of severed nerves.
Randy Lewis, a molecular biologist at Utah State University, says, “We know that that certainly has possibilities for artificial ligaments and artificial tendons, because we know that we can make material right now that’s stronger than a human tendon for the same diameter.”
Christine Radtke, a researcher in nerve reconnection, has found many benefits in using spider silk. Radtke and her team tested this method on sheep (whose nerve endings closely resemble those of humans) and discovered many positive results. “We had a gap in a nerve, and in that gap we put in the longitudinal direction of a spider silk, and we could see nerve regeneration over that gap,” Radtke explains, “And on spider silk, they go crazy. They proliferate. That’s exactly what we need for repair and regeneration. So, if the extremity is moving, it doesn’t rupture, and on the other side, it’s flexible as well, and that’s exactly what we need. It’s a perfect material.” They also observed that during the recovery period, the body would not reject spider silk. After doing its job, the silk would simply be degraded by microfibers and dissolve.
Spider silk also has a lot of potential for the textile industry. Historically, spider silk was woven into garments for royalty in India and China. Queen Victoria also received a gown of spider silk from a Chinese delegation in 1896.
Recently, a team of people spent years collecting Golden Orb spiders from telephone poles in Madagascar and harvested their silks to create a rare textile: an 11ft x 4ft golden cape made entirely of spider silk. It is currently on display at the American Museum of Natural History in New York City.
The properties of spider silk also create the possibility for bulletproof body armor. A bullet can penetrate up to 29 layers of Kevlar. But research shows spider silk to be comparatively tougher than Kevlar and stronger than steel. Hypothetically, spider silk could be woven into a mesh strong enough to stop a bullet and so tightly knit to leave no holes or weaknesses. Because it is more flexible than nylon, it would also provide a non-restricting armor for the entire body. This could also make it the first successful protection for the groin area in bulletproof garments.
If it is so advantageous, why is it not in use?
Despite all the advantages spider silk seems to have, why is it not already being used? One simple answer: it is extraordinarily difficult to harvest, which in turn makes it incredibly costly.
Spiders can not be farmed in the same way as silkworms because spiders are cannibalistic and cannot cohabitate. The silk they produce is also so fine; it would take hundreds of spiders to produce a single square yard of cloth. Creating even the smallest textile out of spider silk would be extremely time-consuming and expensive.
Another challenge is that the silk hardens when exposed to too much air, which creates all sorts of practical difficulties, making it an extremely difficult material to work with.
To take more steps in spider silk research, researchers would need tremendous financing, and cheaper, more efficient methods of harvesting would have to be developed. Also, the Food and Drug Administration would still need to approve of spider silks’ biomaterial use in the medical sphere.
Scientific goals and steps moving forward
However, the beneficial capacity of dragline silk is too great to ignore. Scientists are taking steps to create synthetic spider silk that could replicate natural silks. The question is whether synthetic proteins produced with identical qualities to spider silk creates could be developed through other processes?
Randy Lewis and his team have tried several experiments taking spiders’ silk gene and transferring it to other organisms that would be easier to harvest from. First, they transferred it to an E.Coli bacteria. They’ve also experimented with transferring it to alfalfa plants and even to goats!
The most efficient method so far has been silkworms. Silkworms can be genetically manipulated to produce and spin synthetic spider silk. A significant benefit is that silkworms have been mass farmed for hundreds of years, and scientists are already accustomed to working with them.
Research on spider silks is ongoing, and we have yet to reach the stage where we can cost-effectively and efficiently produce synthetic silk with the same qualities as spiders’ natural spider silk. However, the research is promising, and scientists will certainly continue their patient work unraveling the mysteries of spider silk.
Who knows? We might be looking at a future where we can regenerate human tissue—or create flexible, bulletproof armor like a real-life spiderman. And all from the incredible silks of little spiders.