Oxman Grows Indigo and Melanin Pigment Directly on Knitted Silk

New York design and research company Oxman has grown indigo and melanin pigments directly on knitted silk garments using engineered bacteria, producing color in roughly 24 hours per batch. The company confirmed it is now seeking partners to develop commercial uses for the process, which it demonstrated at prototype scale through four capes titled Velum I through IV.

The process sits at the wet-processing tier of the supply chain, aimed at replacing conventional dyeing rather than changing fiber sourcing. One cape is produced per batch, so volumes remain at laboratory scale rather than production scale.

How does the pigment production work?

The coloration begins before the bacteria touch the cloth. Computer-controlled knitting lets Oxman's team program individual stitches and place fibers coated with chemical inducers at selected points in a three-dimensional silk structure. The textile acts as a growth substrate, which the company describes as a bioreactor.

A bacterial culture is then sprayed onto the fabric. When the bacteria encounter an inducer, a genetic pathway switches on and the cells produce enzymes that assemble pigment from building blocks such as amino acids. The patterns follow the textile's construction and those chemical signals.

Oxman identified the organism as a modified strain of Escherichia coli BL21. The inducers are anhydrotetracycline, or aTc, and C14-HSL. The growth medium contains xanthan gum to thicken the liquid and limit its movement across the suspended textile, plus added tyrosine and tryptophan — amino acid precursors for melanin and indigo respectively. After coloration, the garments are washed and dried, leaving the pigment and pattern behind. Oxman says the chemical inducers wash out during the first wash.

"Color is not applied. It is expressed," Neri Oxman said in a statement.

What does this mean for conventional indigo dyeing?

The company claims its indigo process uses soluble precursors that oxidize into insoluble pigment within the textile, avoiding the chemical reduction step used in conventional indigo dyeing — the step behind much of denim finishing's effluent burden. Buyers should treat that claim carefully. Oxman has not measured the process's overall water, energy or chemical requirements, and has not established comparative environmental savings against conventional dyeing.

"Oxman has not conducted a project-specific life cycle assessment (LCA) for Vigils, and no individual measurements have been taken to date," the company said.

Water figures reported so far are narrow. Velum I used approximately 9 liters of growth medium over roughly 24 hours, a figure that does not account for total process water use, including subsequent laundering. Oxman did not provide a cost comparison with conventional coloration.

Which fibers does the technique cover?

Oxman chose silk for its ability to bind chemically to pigment, as well as its appearance. The underlying inducible-fiber technique has also been tested on wool, cotton, nylon and other commercially available materials, according to the company. Further screening is needed to assess pigment intensity by fiber type and the durability of finished fabrics and garments.

"The performance and durability of the resulting textile are still being documented and validated," the company said.

Durability data is the central gap for any sourcing decision. Preliminary evaluations covered one wash-and-dry cycle using household laundry equipment plus handling of the articles, with no pigment migration or loss observed, according to Oxman. The company identified wash, rub and lightfastness testing under ASTM standards as next steps toward product development, but did not provide specific test designations or performance grades.

Where did the platform come from?

Oxman calls the broader platform Hybrid Living Textiles and links it to research that began with Vespers, a series of 3D-printed masks developed with the Mediated Matter Group at the MIT Media Lab between 2016 and 2019. The final installment, Vespers III, placed engineered pigment-producing microorganisms within UV-cured resin. A separate preceding project, O°, explored footwear and textiles made from polyhydroxyalkanoates, or PHA, a bacterial thermoplastic, alongside fiber production, knitting, 3D printing and biological pigmentation research.

"Design is not design without the ability to tinker with the process itself. To wire genes to fibers, and knitting looms to petri dishes," Oxman said.

What decision does this force?

"The current work demonstrates the technical approach rather than a fully optimized industrial process," the company said. For mills and brands approached as partners, the due-diligence list is concrete: ASTM wash, rub and lightfastness results, a project-specific LCA, cost data against conventional dyeing, and validated results on cotton, nylon and wool rather than silk alone. Until those arrive, Vigils is a materials-science milestone, not a sourcing option.