Silk is the superhero of materials—as strong as a filament of steel, as stretchy as a bungee, yet able to dissolve naturally right back into the carbon cycle. To leverage silk’s special powers, Dr. Ailis Tweed-Kent, an alumna of Notre Dame’s Department of Chemical and Biomolecular Engineering and an M.D. from Harvard Medical School, founded Cocoon Biotech in 2013—a company that uses silk fibroin as a sustainable alternative to microplastics.
In this conversation, Tweed-Kent discussed why she decided to become an entrepreneur and how she has navigated a career path at the intersection of engineering and medicine.
Why silk?
Most people think of silk as an ancient textile—which it is—but it has incredible properties as a protein.
In the textile industry, you unravel a cocoon into a long strand. We reverse that process to return the silk to its liquid protein state. Once it’s liquid, we can manipulate it through chemical engineering to turn it into coatings, films, gels or solids. It’s a platform technology that started in healthcare but has now broadened into agriculture and industrial applications.
Silk comes from silkworms, specifically those on mulberry trees. Is the raw material still sourced the same way?
Exactly. Silkworms—specifically Bombyx mori—are very picky eaters; they only eat mulberry leaves. We source the raw material from traditional silkworm farms in places like China, India and Japan. The silkworm spins a protein from a gland in its mouth to create the cocoon. By returning that cocoon to its liquid protein form, we can mass-produce a material that is completely biodegradable.
Could you explain what guided you along your career path from chemical engineering, to medical school, to entrepreneur?
I remember agonizing over the choice between engineering, business and medicine. The VP for Student Affairs at the time, Father Mark Poorman, gave me great advice: “Choose the path today that feels most aligned with your life, and watch—many more doors will open, some of which lead back to the things you thought you left behind.”
He was right. I went to Harvard Medical School and missed engineering. My mentors there told me, ‘We need engineers in medicine.’ I started this company during my residency. I realized I loved the ‘micro’ of helping one patient at a time, but I also wanted the ‘macro’ impact of building a technology that could affect a whole population.
You practice medicine one day a week. Does that “day job” influence how you solve problems as a CEO?
It keeps me grounded. When you practice, you see the end impact of everything—not just diseases, but how the food we eat or the toxic waste in our environment affects people’s health. It reminds me every week that there is still work to be done.
Startups are notoriously difficult, especially in biotech where things take years to reach the market. How do you handle the pressure and all the unknowns?
You have to be comfortable with uncertainty. I’m a big fan of stories about early explorers, like Shackleton. They had a route and a plan, but they were excited by the prospect of troubleshooting things they couldn’t predict.
In entrepreneurship, you often hit roadblocks. We originally started in arthritis research, but the pharmaceutical industry shifted away from that area. We had to pivot. If you’re solving a real problem, you will find a path forward. Roadblocks often force you to look at the forest rather than the trees.
What advice would you give to students uncertain about their career paths?
You have to love the journey. I see a lot of students wanting to leapfrog to the end result—they want to be the VP or the successful owner, but they don’t like the steps in between. Choose a path where you are learning, having fun, and being challenged along the way.
I also think it’s important to dream big. Look ahead to the problems our generation needs to solve today, and go after those. New ideas and new ways of thinking are what lead to change.
—Karla Cruise, Notre Dame Engineering