The virtues of silk have been well known for millennia. Recently, it’s attracted the attention of certain scientists who, by working on it, have discovered new uses and medical applications for it. The only problem: silk, even to bandage wounds, remains a luxury material.
Young Kim’s team is convinced that silk could revolutionize certain medical methods, as The Verge explained on May 4. The scientist from the University of Connecticut made the surprising finding that silk, known only under for its use as a precious tissue, is actually an extremely resistant material, highly elastic, and compatible with the human body.
Already used in bulletproof vests, its potential appears much broader to the scientist, who wants to integrate it into our bodies to heal our wounds or reconstruct broken bones. There are two types of silk, with different properties: the kind that worms spin into cocoons, and the kind sewn by spiders into webs. The former is less resistant than the latter, but both are strong and elastic enough to be used in the human body, Young Kim says.
After identifying that certain natural proteins, activated by green light, can create a chemical reaction that eradicates pathogens, the scientist’s team injected a super-protein called mKate2, a red fluorescent, into silkworm DNA. The silkworms started producing a glowing silk, onto which the researchers deposited a bacteria. They lit up the resulting green fabric for an hour. After that, they realized that the survival rate of the bacteria had reduced by 45%. It’s a chemical process very similar to one produced by hydrogen peroxide, known for its antibacterial properties.
Questions remain. Like hydrogen peroxide, this process doesn’t distinguish bad from benign bacteria. We also don’t know how long, at minimum, we need to expose the silk to light for the process to work. But the discovery, published by Advanced Science, is definitely promising, with wide-ranging potential applications, particularly in air and water purification devices. The same team of researchers also identified the physical properties showing that silk also contains cooling qualities, which could then be used as a bandage against inflammations.
Along with its healing properties, silk could also help reconstruct broken bones. Today, doctors use pieces of metal to stabilize fracture zones. Usually made of deoxidized steel and titanium, these materials are inconveniently stiff and are likely to cause future fractures, says Mei Wei, a materials science specialist at the University of Connecticut. Furthermore, putting metal in our bodies requires a posterior surgical operation, when the bone is healed, to take them out.
From fibroin, a protein extracted from spider silk, Professor Wei has created a solid, elastic, biodegradable material in the body in just a year, the result of a combination of the protein with a kind of calcium naturally present in our bones and a form of plastic. According to him, the repaired bone would then be stronger than natural bone. The process is still in development before it goes through animal testing and eventually clinical trials.
Valuable in more than one sense
As often is the case with new innovations, the problem is price. Silk, made organically by animals, is extremely difficult to make affordably. Silkworms are rare and difficult to raise on a large scale. And nobody’s particularly interested in tending spider farms.
Daniel Söderberg, scientist at the Royal Institute of Technology in Stockholm, proposes designing a strong and cheap material by extracting the solid nanocellulose present in wood, which helps keep trees upright, and combining it with silk to make it more flexible. It could, for example, replace tendons, which due to their elasticity are very difficult to replace.