Silk has been valued for millennia, but in recent years it’s gained attention from the scientific community as well. That’s because it’s an extraordinarily strong material when woven together like in bulletproof vests, but it seems silk can also be used for a variety of purposes inside our bodies too.The potential of silk is more than just protecting the outside of our anatomy, however, and researchers are now engineering silk so it can one day heal our wounds, hold up our bones, and become part of our bodies.
In a recent study from Purdue University, scientists bio-engineered silkworms to spin a form of light-activated silk that disinfects. They first identified all-natural proteins that could be activated by a specific type of light, which kicks off a chemical reaction that kills pathogens. Then they inserted this protein, mKate 2, into the DNA of the silkworms, which caused them to produce a red, glowing silk that’s activated by green light.
How was the test done:
In their tests, the team put E. coli bacteria on the red silk and shined a green light on it for an hour. What they realized is that the silk created a natural hydrogen peroxide-like effect to disinfect the bacteria, dropping its survival rate by 45 per cent, the study reported.
For now, the drawback is that the activated silk can’t different between harmful and benign pathogens, just like hydrogen peroxide, and scientists don’t yet know the minimum time they need to shine a light for the silk to be effective. However, it’s still an exciting discovery, as the new kind of silk could have a variety of applications, like in air and water purifiers. In another recent paper, Kim and his team also figured out the exact physical properties that make silk so cooling. This could be manipulated to make silk even more effective at cooling, which is useful to treat inflammation. That, combined with the light-activated disinfectant properties, could make silk an advanced bandage of the future.
It doesn’t end there either. In a study from the University of Connecticut, researchers discovered they could use silk to prop up broken or fractured body parts, instead of traditional metals like stainless steel and titanium. These metals are stiff and can sometimes even cause fractures themselves after being installed, according to the research head Mei Wei. Not to mention that you need another surgery to take out the metal once the bone has healed.
Instead, Wei and her team created a new kind of silk that’s strong enough to hold bones together, but is also flexible to avoid causing damage. In addition, it degrades within the body after a year, meaning there’s no need for a follow up surgery for removal. To do this, they combined a protein found in spider silk called fibrin, with a form of plastic and a type of calcium that’s found in our bones. The result is a material much stronger than bone, and one that’s still bio-degradable within our bodies.
The only problem is that silk is expensive because of how hard it is to raise silkworms (or spiders for that matter), but scientists are working on that problem too. Daniel Söderberg, a researcher at KTH Royal Institute of Technology in Stockholm, think we can get around that problem by combining silk with the nano cellulose within trees. It helps make the silk stronger, without having to harvest as much of it. In fact, his hybrid material is as strong as Kevlar, which is used in bulletproof vests.
Most importantly though, he believes that it can one day be used to replace body parts. While silk breaks down in the natural world, the nano cellulose prevents this from happening inside the human body. Yet it’s safe enough that cells will continue to grow on and around it, meaning it could be used to replace parts that need to remain strong and flexible, like tendons.
All we’re waiting for at this point is for silk harvesting to become more economical. When that happens, we could witness a revolution in medicine, all on the backs of two little insects.