(Photo: Wolfgang Kumm/AFP/Getty Images)

Take a look at the tag of your shirt and chances are you'll see the words "polyester" or "nylon," the synthetic fibers floating on the market alongside cotton since around World War II. They're cheap, stretchy, and stain resistant—but derived from fossil fuel hydrocarbons, so unlike cotton, silk, wool, and leather that decompose over time, they last an eternity in landfills.

But those natural, biodegradable fibers have a downside too: derived from farmed plants and animals, they take a significant toll on the planet. So what if scientists could hack the biology within cells, and use them to make fibers? Think of the possibilities: perfect sheets of leather of any color, thickness, pattern, and size; silk that stretches; and cotton that communicates with your smartphone.

The idea is part of a larger movement toward sustainability, including the search for substitutes to products like meat and eggs. Indeed, leather is a byproduct of the meat industry, so the plan to create "unnatural" natural meat could help end the costly, unsustainable practice of rearing cattle.

Enter the burgeoning field of "biofabrication." The past five years have seen this niche movement grow into companies on the verge of leather without cows, and new materials like yarn made out of spider webs (you got it—without the spiders!). We're not talking materials simply inspired by biology, like pleather, but rather fabric built from the very same natural materials, not unlike how we make beer.

All "Unnatural" Natural

How do you make an "unnatural natural" material? Clothing materials, natural and synthetic, are made up of polymers: one molecule repeated over and over to create fiber, which is then spooled, woven, or meshed into a garment. In cotton, that repeating molecule is a carbohydrate called cellulose. In the case of leather, once all is said and done to a skin, polymers mostly comprise a structural protein called collagen. Silk fibers are made from a protein called "fibroin."

In other words, if we can recreate those proteins and decipher how they naturally assemble, then we can isolate the process by which these materials are generated in a test tube. Going a step further, you might modify each building block, for instance by linking a pigment molecule that creates a specific color, or inserting some other material to give it a stretchy property. The world is your oyster!

For decades, scientists have known how to take a gene from almost any animal, stick it into a single-cell organism, such as yeast, and make the unsuspecting host read out that gene as a protein product.

Perhaps the most popular cell factory is yeast, easy to manipulate, quick to grow, and difficult to contaminate with microbes—as the ancient Egyptians discovered when they invented a low-alcohol beer to drink like water.

In modern times, an early application of this "recombinant DNA technology" was the production of human insulin in E. coli by Genentech in 1978. Before then, diabetics relied on insulin extracted from pigs, which sometimes caused an allergic reactions in humans. Genentech's simple technology turned the industry on its head by producing human insulin through similar means to how we make beer, with yeast. Since then, this technology has formed the crux of an industry of protein-based therapeutics called "biologics."

The problems of unnatural natural fibers isn't so different from those facing Genentech almost four decades ago. The primary difference is that a vast amount of genetic information is readily available today, due to modern technology. Whereas recombinant insulin required half a century of research, today—thanks to the ability to quickly sequence and analyze DNA and RNA—it may take weeks to a few months to go from a gene to producing its protein product.

Fabric Without Spiders or Cows

A couple of forerunners in the biofabrication industry are Modern Meadow, which offers leather without the cow, and Bolt Threads, which weaves yarn out of spider webs. Founded in 2011 and based in New Jersey, Modern Meadow produces collagen using yeast, followed by the assembly of that collagen into fibers, later meshed into leather. BoltThreads, based in northern California, is making a silk-like material borrowing from the biochemistry of spiders. Both companies recently unveiled items at an ongoing exhibition at New York's Museum of Modern Art (MoMA).

Among its executives, Modern Meadow boasts the designer Suzanne Lee, the founder of the consultancy Biocouture, an early pioneer in biofabrication. With the unveiling of its "graphic T-shirt" made of its proprietary leather material at the MoMA, Modern Meadow announced the launch of its first brand, ZOA, which will ostensibly release a first round of consumer products.

Meanwhile, BoltThreads teamed up with a renowned eco-designer, Stella McCartney, to weave a dress that evokes Rumpelstiltskin's golden silk, and is also on display at the MoMA. The company currently offers a limited edition tie made entirely of its biofabricated spider silk, and, according to its website, promises "some neat stuff" next year.

Several other start-ups have embraced biotechnology. A San Francisco synthetic biology incubator, IndieBio, hosts start-ups like Mycoworks, which is making a fungus-based alternative to leather, and BioLoom, which claims to grow cotton fibers using yeast. These companies are forging unorthodox collaborations between scientists, product designers, and engineers, like a crop of fellow programs popping up around the globe. The Massachusetts Institute of Technology recently recently announced its Advanced Functional Fabrics Institute, while the University of Utrecht, in the Netherlands, has opened the first masters program dedicated to biofabrication.

"Smart" Fabric (and Glow in the Dark)

With this revolution, consumers should expect a wave of "smart" materials that incorporate new technology into fibers themselves. Nascent proposals include garments that change color with the temperature, or that act as early detection diagnostics for medical conditions by interacting with certain ingredients in sweat. In a recent paper, appearing in the journal Science, a team of researchers from Germany and Austria claims to have biofabricated a "functionalized" cotton fiber by "feeding" cotton plants a modified glow-in-the-dark version of the sugar building block that makes up the cotton fiber.

That paper is pending revisions, which may ultimately change its reported results. But the authors have already nearly made their point: that new "unnatural" materials can imbue fabrics with "smart" properties.

As with any emerging and disruptive technology, some leading voices have raised potential ethical issues that may come from biofabrication.

One particularly poignant remark being made by the Slovenian designer Tina Gorjanc is to make "leather" garments from skin grown using the DNA of Alexander McQueen, the late designer and provocateur​. Gorjanc aims to use her work to highlight the potential for corporations to exploit human DNA, harkening to the longstanding use of human cells derived from unsuspecting patients in medical research, such as Henrietta Lacks, whose "immortal" cells have been studied for decades.

Moreover, companies like Bolt Threads and MycoWorks, promising entirely new materials, will have to convince traditional textile makers that their products can truly replace non-sustainable materials. But with companies like Adidas and Nike as sponsors at the International Conference on Biofabrication, these newfangled materials increasingly sound like more than a pipe dream.

This story originally appeared on Massive, an editorial partner site that publishes science stories by scientists. Subscribe to their newsletter and follow Massive on Facebook and Twitter.