At a New York design studio, you'll find four capes. They hang off a mannequin in soft folds, each knitted from a single piece of silk. Their color is uneven. Deep indigo collects in the ridges of the material, black shades in the valleys, blues appear in slightly crooked lines. The pigment is streaked and faded, so no two sections look the same. A commercial dye house would call this a defect and throw it out. But here, the inconsistency is the point.
The color on the fabric was not produced by dyeing. Instead, it comes from a process that mimics the way nature gives fruits, flowers and animals their color. The hues on these garments were grown into the material over the course of 24 hours by billions of engineered bacteria.
For the designer behind the project, this offers an alternative to the way the apparel sector colors clothing. Textile dyeing and finishing accounts for a large share of the world's industrial water pollution.
"There's a wide array of relationships between design and nature," she says. "You can extract dyes from flowers and use them in textiles, or you could replicate the exact genetic code in a bacteria to express that color."
How to grow color
It's possible to program the genetic code of a microbe to build almost anything. In this case, the team inserted genes that instruct bacteria to produce two pigment classes, indigos and melanins, the same molecules behind the blue in denim and the brown-black of hair and skin.
For Marcus Walker, a synthetic biologist who worked on the project, it's important to consider where color comes from in the living world. A tiger's stripe or the swirl in a fingerprint aren't painted on; individual cells read their position and identify what pigment they should produce. "If you think about how nature dyes things, it comes from the inside out," Walker says.
Borrowing from this logic, the team coats fibers with a chemical that the bacteria can sense. They then spray the whole garment with a bacterial culture, and the pigment appears only where those coated fibers have been knitted in, which allows the team to create patterns in the fabric.
"You cover the whole textile in those bacteria," Walker says. "But only where we've knitted particular coated fibers will you get the pigment response that you've encoded into the bacteria."
The project doesn't depend only on the bacteria to work. It also requires thinking about the texture of the fabric. A textile engineer knits the capes on an industrial machine, the kind used to knit sneaker uppers, from silk whose filaments are close to the scale of the bacteria.
A lab that works alongside nature
Inside the studio, roughly two dozen researchers work on projects at the intersection of engineering, data science, biotechnology and design. One room reconstructs the atmosphere in New York on a specific day in 1864. In another, scientists monitor an ancient oak-tulip tree forest to see whether they can restore old ecosystems.
"You can move from a robot to a computer to a pipette in 30 seconds," the designer says, noting that the lab's mission is to treat nature as a collaborator, rather than a resource to be extracted from.
The project is still experimental, but the long-term goal is to scale the technology up.