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Renee Farris headshot

Spiders Are Making Your New Silk Clothes


“Happy birthday! I got you a shirt made out of spider butt silk.” You might hear these words next year.

Butts can be sexy, funny and comfy to sit on. But they have never manufactured anything useful to humans. Until now.

A startup, Bolt Threads, is turning a silky supermaterial from spider butt ducts into sports bras, athletic shirts, and potentially artificial tendons, plastic bottles, iPad covers and suspension bridge ropes. Seriously.

The silky material is five times stronger than steel, tougher than bulletproof Kevlar and softer than wool. It can stretch up to 40 percent its normal length and can be waterproof. It’s also more eco-friendly than land-demanding, water-guzzling cotton or petroleum-based polyester.

Want to take your iPad kayaking? It’s cool, just put it inside your waterproof spider butt silk case. Walking through a shady part of town? Wear your bulletproof spider butt silk jacket.

Inquisitive textile designers have tried to create material from spider silk for decades. Contrary to popular belief, the ancient Chinese Silk Road trade route was not an international highway for spiders. However, several years ago, 70 people spent four years collecting over a million wild spiders and 80 feet of spider silk. All this work only produced an 11-by-4 foot textile. That’s a little larger than a yoga mat … the most expensive yoga mat in history, which is now on the wall of a natural history museum.

The hurdle has been scaling production. The inventors of the Bolt Threads silk originally purchased a swarm of spiders and let the spiders spin webs all over the office. There’s no word as to whether they also purchased flies to release into the office to feed the spiders. According to Bloomberg Business, “One day a well-known [University of California, San Francisco] molecular biologist walked in, saw a spider hanging in a doorway, and ran away screaming.” The biologist’s whereabouts remain unknown, but people suspect Antarctica where it’s too cold for spiders to live.

Not only is it hard to handle the quantity of spiders required, spiders are territorial and cannibalistic and turn spider farms into war zones. If spiders could go to counseling, do some team building exercises like trust falls and work together, they could be brilliant entrepreneurs.

Due to these complications, the scientists ditched the idea of spiders producing the silk. Instead, they studied the way spiders produce silk then mimicked the process. The scientists bioengineered yeast cells that grow during fermentation – similar to the way beer is made. The yeast cells produce protein. The liquid protein gets squeezed through holes that mimic the spider’s spinneret and drop into a bath of water, salt and sugar. This solidifies the protein into strings of fiber.

Afterwards, the strings are laid out to dry then shipped off to be spun into fabric. Using this method they can produce spider silk without the spiders. The production is now measured in metric tons instead of ounces.

The yeast cells can be genetically modified to produce different types of silk and create a variety of levels of softness, durability and strength. Want a softer fabric? All you do is change the protein sequence.

According to investor Steve Vassallo with Foundation Capital, “Bolt Threads is uniquely positioned to commercialize technology that people have dreamt about for decades.”

Bolt Threads is exploring two business options: 1) manufacture their own clothes, or 2) sell the technology to a clothing brand. Another revenue model to consider would be bringing back the thousands of spiders and renting out their building during Halloween.

The company plans to expand production by partnering with manufacturers such as the Michigan Biotechnology Institute which will produce synthetic silk in their 4,000-liter tank.

The next time you go to stomp on a spider, think twice. Remember, it’s the reason you’re wearing an eco-friendly athletic shirt. Instead, pick it up and give it a kiss, or at least toss it a dead fly.

Flickr photo credits: 1) Yogendra Joshi, 2) Uditha Wickramanay, 3) Apryl Wiese, 4) Siamesepuppy

Renee Farris headshotRenee Farris

Renee is a social impact strategist who works with companies to help them focus on key social and environmental opportunities. She loves connecting with people so feel free to contact her at renee.a.farris@gmail.com.

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