Johns injects less than one-tenth of a teaspoon of a mixture of silk and hyaluronic acid through a special catheter wired through his endoscope. He keeps patients awake for injections, sitting upright on that wicker chair. The procedure is completed in about two minutes. Like other vocal cord injections, the results appear immediately. The gel fills the tissue, strengthening the anatomy until healthy tissue can grow back and take over. “These people are very happy,” Johns says. “These are some kind of life-changing actions.”
The study with Johns will take about two years, but SilkVoice has already been approved for human use. So far, Hoang-Lindsay says, most of the 40 people who received the injections have kept their improvements.
Meanwhile, headquarters in Boston a startup called Mori quietly commercialized silk as a way to protect food.
As a postdoc for materials engineering at Omenetto’s lab in 2014, Benedetto Marelli accidentally invented a food waste repair. “In the lab, we had a cooking competition where we had to cook from silk,” Marelli says. He imagined dipping strawberries into regenerated silk silk, as if it were a transparent fondue. The result was irresistible. He lost the competition, pushed the strawberries aside and forgot about them. A week later, half of them were completely rotten. The others still looked fresh. Silk protein created a thin layer that adapted to the surface of the fruit. The water stayed inside and no oxygen remained, Marelli says. Bacteria digest silk too poorly to contaminate the products buried below.
From that idea, in 2016, Marelli started Cambridge Crops, today known as Mori, to deal with food waste and insecurity by coating perishable materials to make them last longer. “I like to use an example of zucchini noodles,” says Mori CEO and co-founder Adam Behrens. Unlike wax, Mori coating can adhere to both water-repellent and porous surfaces, such as the outside and inside of zucchini.
The company integrates a spray coating – or immersion coating, like Marelli’s lucky accident – directly into food washing and packaging processes. For example, leafy greens and cherries often go through cleaning cycles before they reach food. (Marelli, now an associate professor of civil engineering and environmental protection, is still a consultant and shareholder, but has distanced himself from their business.)
Last year, a group of allergists, toxicologists and nutritionists labeled the coating as “generally recognized as safe,” meaning the public can buy and eat it. Mori already has pilots working on farms and food companies across the U.S., and more production should begin later this year.
These startups aren’t the only ones focusing on silkworm silk. Vaxess, another Tufts spinoff, makes silk patches on microneedles for a single-dose vaccine. Their patch stores sensitive vaccine antigens in the tiny tips of silk microneedles and can work with conventional vaccines already approved by the FDA. They aim to make stable vaccines that will be easier to administer, according to Kluge. The Gates Foundation has supported some of their animal testing, and Kluge says phase 1 human safety studies should begin early next year. (Omenetto and Kaplan are the scientific co-founders of Vaxess, Mori, and Sofregen.)
While raising silkworms can spit out cocoons worth nine Eiffel Towers each year, scientists have not given up trying to persuade them from other creatures. “Spider silk is stronger than the silkworm beetle and is more resilient,” says Lewis, a former biologist at the University of Wyoming who has taken over a herd of BioSteel goats. (She’s in Utah now.)
But breeding spiders is still out of the question. So Lewis spent decades looking for a workaround. In the late 1980s, he consulted with a company that had found a way to assemble long, repeating chains of amino acids – new proteins. They asked him if he could use it to make spider silk. “The problem was that there was literally no information about proteins on the silk spider,” Lewis says.