The race to put silk in almost everything


Johns injects less than a tenth of a teaspoon of the silk-hyaluronic acid mixture through a special catheter wired through his endoscope. He keeps his patients awake for injections, sitting upright in this leather chair. The procedure is completed in about two minutes. Like other vocal cord injections, results appear immediately. The gel swells the tissue, firms the anatomy until healthy tissue can grow back and take over. “These people are very happy,” says Johns. “These are life changing procedures for them.”

The study with Johns will last around two years, but SilkVoice is already cleared for human use. So far, says Hoang-Lindsay, the majority of the 40 people who received the injections have kept their improvements.

Meanwhile, a Boston-based company Startup Mori quietly marketed silk as a way to protect food.

As a postdoctoral fellow in materials engineering in Omenetto’s lab in 2014, Benedetto Marelli accidentally invented a solution to food waste. “We had a cooking competition in the lab where we had to cook with silk,” says Marelli. He was considering dipping strawberries in regenerated silkworm silk, as if it were a clear fondue. The result was disappointing. He lost the contest, pushed the strawberries aside and forgot about them. A week later, half of them were completely rotten. The others still looked fresh. The silk protein had created a thin layer that conformed to the surface of the fruit. The water stayed inside and the oxygen stayed outside, says Marelli. Bacteria digest the silk too slowly to contaminate the products buried underneath.

From that idea, in 2016 Marelli launched Cambridge Crops, now known as Mori, to tackle food waste and insecurity by coating perishables to make them last longer. “I like to use the example of a zucchini noodle,” says Adam Behrens, CEO and co-founder of Mori. Unlike wax, Mori’s coating can adhere to both water-repellent and porous surfaces, such as the exterior and interior of a zucchini.

The company integrates spray coating – or dip coating, like the lucky Marelli accident – directly into the food washing and packaging processes. Leafy greens and cherries, for example, often go through cleaning cycles before they reach grocery stores. (Marelli, now associate professor of civil and environmental engineering, remains an advisor and shareholder but has withdrawn from their operations.)

Last year, a panel of allergists, toxicologists, and nutritionists named the coating “generally recognized as safe,” meaning the public can buy and eat it. Mori already has pilot projects at farms and food businesses in the United States, and larger-scale manufacturing is expected to begin later this year.

These startups are far from the only ones focusing on silkworm silk. Vaxess, another Tufts spinoff company, makes disposable silk micro-needle patches for dispensing vaccines. Their patch preserves 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 long-lasting vaccines that are easier to deploy, according to Kluge. The Gates Foundation has supported some of their animal trials, and Kluge said Phase 1 human security studies are expected to begin early next year. (Omenetto and Kaplan are the scientific co-founders of Vaxess, Mori, and Sofregen.)

While breeding silkworms can spit out the equivalent of nine Eiffel Tower cocoons each year, scientists have not given up on trying to coax the same from other creatures. “Spider silk is stronger than silkworm silk and is more elastic,” says Lewis, the former University of Wyoming biologist who took over the BioSteel goat herd. (He is now in the state of Utah.)

But spider breeding is still out of the question. Lewis therefore spent decades looking for a workaround. In the late 1980s, he was a consultant for a company that found a way to put together 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 on the proteins on spider bristles,” says Lewis.



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