How much chemistry is in the clothing we wear—and is it really good for our health? Boston-area Silk Therapeutics thinks its patented liquid silk technology can replace some of the chemicals commonly found in performance fabrics and make a better apparel product in the process.
The company got its start in 2013 making skincare for women going through oncological treatment, with a mission to use liquid silk as an all-natural replacement for the many lab-grown synthetics and fillers commonly used in the beauty industry. Putting all of those unnatural excess chemicals on one’s skin could be harmful, the thinking goes, so why not make a more skin-friendly product using nature’s own innovation: silk from a silkworm?
After building the successful Silk Therapeutics skincare brand, the Medford, Mass.-based biomaterials firm is now focusing its attention on how liquid silk could transform the apparel industry. The company, co-founded by Drs. Greg Altman, CEO, and Rebecca Lacouture, COO, raised $11 million last fall from Robert Kraft of the Kraft Group, Tampa Bay Lightning owner Jeff Vinik, Roy P. Disney, Lear Corporation and Altman Health Investments to bring this new ambition to life, boosting its total funding to $21 million.
According to Unilever, the market for sustainable products could be worth more than $3 trillion, presenting a lucrative opportunity for brands seeking to connect with eco-conscious consumers embracing the wellness movement in all areas of their lives. Sustainability has been a hot topic in the apparel industry in particular, as major brands like H&M, Gap Inc. and others highlight their efforts in areas like garment and textile recycling, alternative material innovation and water conservation and management.
All of these things could pave the way for Silk Therapeutics’ foray into an industry on the hunt for sustainable ways to achieve the performance benefits that apparel wearers now expect as the norm. Though consumers have enthusiastically adopted the comfortable stretch performance fabrics of the athleisure and activewear movements, they may not know how many chemicals are added to many of these textiles to achieve in-demand properties like moisture wicking or odor control.
Inside the end-to-end sustainability of liquid silk
Silk Therapeutics’ innovation starts with the caterpillar of the Bombyx mori, of course—also known as the silkworm, an insect native to China and the Far East that prefers a nearly exclusive diet of mulberry leaves. They’re picky eaters, in a good way—treat a mulberry tree with pesticides and the worms won’t consume the leaves, explained Altman, who used his Tufts University bioengineering Ph.D. to discover methods of purifying natural silk. This pesticide-free diet ensures a petrochemical-free product from end to end, Altman added.
The silkworm’s cocoon serves as its home until it emerges as a silkmoth, and it builds this temporary domicile from a single thread of silk wrapped continuously in what Altman described as a “natural bobbin of yarn.” But in addition to the fibroin silk protein that’s so desirable in the textile industry, the cocoon also contains sericin, a protein that acts as the structural glue holding the worm’s miniature shelter together. Silk Therapeutics boils the cocoons in two different salt baths, the first of which separates the sericin “glue” from the fibroin protein and the second of which dissolves the solid silk into liquid form through a careful cocktail of time, temperature and filtration. Even the salt from this process can be recycled to prevent excess waste, Altman explained. “The process is almost more economical than synthetic chemistry,” he added.
It takes just 15 days for the silkworm to produce a cocoon. Though the insect commonly is harvested for food in many countries after the cocoon is created—a fact that has drawn ire from the likes of Mahatma Ghandi as well as PETA—Silk Therapeutics allows the chrysalis to metamorphose into a silkworm to support a fully cruelty-free process, Altman said.
Rhode Island was a U.S. production center for silk back in the 1970s, and Silk Therapeutics wants to bring domestic silkworm farming back, actively searching for community farmers interested in growing silk.
“It literally involves planting a crop of mulberry trees, then picking the leaves and feeding the worms, letting the worms live their natural life cycle and sending us basically the ‘trash of the worm,” Altman said.
Stakeholders in the silk textile world generally try to farm the biggest and best cocoons because they provide the longest fiber. “For us, we need only the silk protein by mass,” Altman explained. “We don’t need high quality fiber. So we can take all the leftover cocoons that don’t make the grade in the textile industry. That’s what helps us make our product much more economically viable.”
What’s more, the startup has thought about how best to manage the supply chain. For example, it’s developed a modular system to enable manufacturing in place. This means that if silk is being produced in Vietnam, portions of the manufacturing technology can be relocated to the production site, according to Altman. On top of that, because the sericin “glue” accounts for nearly one-third of the weight of each cocoon, removing it prior to shipping can reduce costs significantly.
Liquid silk for performance apparel
“One of the things that we are deeply passionate about using silk for is to remove the unseen and hidden uses of synthetic chemistry in apparel, textiles and product that can contact our skin and get into our bodies,” Altman said. “The less we absorb, the less we tolerate, the healthier we are. It’s a public health concept.”
On their own, nylon and synthetic fabrics, commonly used in yoga pants, sports bras and more, don’t control moisture well, prompting the need for additional treatments to achieve the desired benefits. “We basically coat the apparel we wear with synthetic chemistry that changes the surface characteristics,” Altman said of how performance fabrics traditionally are created. “We have all of these antimicrobials, heavy metals, silvers, zincs and more that are just washing away and going into the waterways.”
That’s where liquid silk comes in. Nylon treated with a “nano-layer finish with liquid silk” offers similar moisture-wicking properties as do the usual chemical applications, according to Altman. “If it comes in contact with your body, it’s biocompatible and it doesn’t wash off, but if it does, it’s certainly not going to pollute our waterways,” he added. “This technology, frankly, has been in front of us for thousands of years.”
Liquid silk is applied at the yarn or fabric level after dyeing, during the point in the process when synthetic chemicals traditionally are incorporated to seal in the dye, Altman said. “That’s the entire goal—don’t change the manufacturing process at the mill because the moment you do it’s not going to happen,” he said. “Every brand has to compete right now on cost. We needed to find a way to price into the market without undue burden and I believe we’ve already achieved it.”
So far a global women’s performance apparel retailer is evaluating Silk Therapeutics’ liquid silk technology for its products, Altman said. However, though the company’s initial focus has been on performance apparel industry and synthetic fibers, it’s finding that there are applications for natural fibers like wool, cashmere, cotton and leather, too. “The opportunity to do good with silk is much, much bigger than we thought,” Altman added.
The R&D behind liquid silk
In addition to all of the talent coming from the Boston area’s exceptional university pipeline, Silk Therapeutics maintains a small facility in North Carolina to take advantage of the braintrust of chemists and Ph.D.s produced by North Carolina State University and nearby schools.
“We’re bringing together the biotech and textile worlds,” Altman said. Though Silk Therapeutics employs 30 today, the company plans to double that figure over the next three months.
Altman pegs the company’s R&D spending at roughly 50 percent of its total budget. “We have a broad umbrella for what we think of as research and development,” he explained. “Most people think about R&D as product development, but we also think about process development. So if we’re innovating a new process, that, too, falls into R&D, which would put our spending at almost 60 percent or 70 percent of our budget.”
However, those numbers will begin to shift later this year and into 2019 as the company evolves.
“Now that we’ve validated the technology and the ability to produce at scale, we need to figure out how to tell people about it,” Altman said. “We’re in the process of bringing in an extraordinary brand team to help us tell the story of how a little silkworm is going to change the world.”
As more consumers demand transparency and trust in the products they buy, Silk Therapeutics wants to open the doors to its inner workings (though it’s not giving away trade secrets, naturally).
“We can’t just be a forward-facing brand. We have to bring people into the process,” Altman said.