Silk Can Keep Your Food Fresher—and Make Your Glue Stickier

Tufts researchers have discovered innovative uses for silk in medicine, from surgical screws that dissolve once they’re no longer needed to gloves that can detect the presence of viruses. And the breakthroughs from the university’s Silklab extend beyond biomedical materials.

Here’s a sampling of the lab’s other discoveries.

A Protective Barrier for Food

For Halloween one year, Silklab Director Fiorenzo Omenetto and a colleague combined sheets of silk protein with blood left over from samples used in an experiment and prepared to scare folks.

Instead, they surprised themselves: The blood stayed fresh and bright red for months. That discovery led the researchers to create an edible, transparent, tasteless film of silk that can protect foods—fruit, nuts, meats, and more—by keeping moisture in or out and holding pathogens at bay.

A company called Mori grew from the research and is already selling products such as silk-covered spinach. Omenetto hopes that the findings will reduce global food waste and revolutionize food safety.

Nonstick Wonder

Chemically modifying the basic protein element of silk—fibroin—changes silk’s properties.

Tufts researchers, including Robinson Professor of Chemistry Krishna Kumar and Assistant Professor Luke Davis, have taken advantage of this fact to develop materials that refuse to stick to water and other fluids.

Nonstick silk can be molded into forms like plastic or coated onto surfaces. It has properties that surpass those of typical household nonstick items and could potentially enhance a wide range of products. Imagine, for example, automotive windshields from which rainwater just rolls off without the use of wipers.

Medical devices can also be improved with the material. Using it to prevent detrimental interactions with water could preserve the devices’ strength and integrity. 

A Sticky Situation

Try chipping a mussel off a seawall or a barnacle off the bottom of a boat—nature makes powerful adhesives.

Researchers in the Silklab have used silk protein to replicate key features of such adhesives, including protein filaments, chemical crosslinking, and iron bonding. The result is a powerful nontoxic glue that sets and works as well underwater as it does in dry conditions and is stronger than most synthetic glue products on the market.

There are benefits beyond the glue’s strength, according to Omenetto. “Because the material is made from extracted biological sources, and the chemistries are benign—drawn from nature and largely avoiding synthetic steps or the use of volatile solvents—it could have advantages in manufacturing as well.”

Better than Leather

Leather is a multibillion-dollar industry requiring the destruction of more than 3.8 billion bovine animals each year. The environmental damage? Deforestation, water and land overuse, environmental pollution, and greenhouse gas emissions.

The Silklab has an alternative: silk proteins repurposed to form a material with the same texture, durability, flexibility, and stiffness of leather.  

While alternative leathers already exist, silk-based leather manufacturing offers advantages. It is water-based, uses only mild chemicals, is conducted at room temperature, and produces mostly nontoxic waste. The silk-based leather is also biodegradable once it enters the waste stream, and products made from the material can be dissolved and regenerated into new items.

“Our work is centered on the use of naturally derived materials that minimize the use of toxic chemicals while maintaining material performance” to provide alternatives to common products, said Omenetto. “By using silk, as well as cellulose from textile and agricultural waste and chitosan from shellfish waste, and all the relatively gentle chemistries used to combine them, we are making progress towards this goal.”