Spider silk has long captured the imagination of scientists and comic book writers alike. Extremely strong, yet amazingly elastic, spider silk has some seriously desirable properties that we could put to fantastic use. While Spider-Man has been spinning his own silk since 1962, unlocking this superpower has proved to be an enormous challenge for normal humans.
A spider's spinneret - the organ that spins spider silk into fibers - is incredibly complex, and scientists have worked for years to develop a human-made version. But in a recent paper in Nature Communications, researchers announced they've finally done it. The new device is just a few inches long and extrudes the silk through microsized channels that mimic a spider's spinneret. And just as Spider-Man uses his web shooters to rescue people from danger, humans may soon be able to save lives by deploying their own version of spider silk.
In the comic book world, it's external dangers like supervillains that pose the most major threats to people's safety. Thankfully, there Spider-Man can sling a web to ground the Green Goblin's glider or stick Doctor Octopus' arms to each other. But in the real world, the most worrisome threats to our safety tend to come from within our own bodies. And according to Markus Buehler, professor of civil and environmental engineering at MIT and a senior author of the study, spider silk could really help us out at saving lives from such internal dangers as well.
Human-made silk's valuable properties could be used to improve medical technologies ranging from sutures to organ replacements because "the human body will not reject the silk," he told Tech Times.
One of the major challenges in medicine is saving patients from organ failure. According to the U.S. Department of Health and Human Services, the waiting list for organ transplantation gets longer every 10 minutes and an average of 21 people die every day while waiting for an organ transplant. Organ donations simply aren't sufficient to meet the demand for organ transplants, spurring researchers to develop ways to create new organs in the lab, including 3D-printing them using cells as the "ink."
Silk produced by this new device is "a lot more modifiable than spider silk," and this versatility could make it possible use the silk to create synthetic organs, Buehler says. He explains that the way this silk-spinning device works is that it assembles the silk from two main components that are found in natural spider silk. One component is made of densely packed silk proteins and the other is made of more loosely connected silk proteins.
"You can imagine it as a brick and mortar structure where the mortar is the softer components and the bricks are the denser components," says Buehler.
Like a brick wall, the two components have to be arranged in a particular way to create a stable structure. Using very advanced computer simulations to gain a better picture of what these proteins are doing at the molecular level, the researchers were able to figure out how spiders build the foundation for their silk. The synthetic silk that the device produces isn't quite as sophisticated as a spider's silk, but it uses the same basic blueprint. The next step for researchers will be to embellish this plain "wall" with decorations that suit our needs.
"What if you build the wall, but then you add some hooks for other things to be attached? In the biological system, the 'hooks' would be used to attach cells to those walls," Buehler explains.
In this way, the silk would serve as a sort of scaffolding for building synthetic organs. Right now, Buehler and his colleagues are working on adding elastin, a stretchy protein found in our own skin and lung tissue (and in the bungee cord-like nerves of whales), to the silk. Since this protein is found in our bodies naturally, our cells are programmed to react to it in a particular way. Knowing this, scientists could manipulate cells using the silk in such a way that they grow into new organs.
"If the silk material has new proteins on its surface, like elastin, the biological system can be directed to do certain things and grow certain kinds of tissues," Buehler says.
So doctors won't exactly be saving their patients by shooting webs at them using silk spinners strapped to their wrists, although Buehler does acknowledge that the artificial spinneret "is definitely small enough to be a wearable device." And similar to Spider-Man's web shooters, the new device isn't limited to producing one puny strand of silk at a time.
"Now that we have a spinning device we can make one device that has thousands of spinnerets," says Buehler. "In a natural spider you have one."
The modifiable design of the silk also could allow scientists to create silk that is even stronger than natural spider silk. Researchers recently accomplished this by spraying spiders with graphene, but the artificial spinneret device would allow them to do so without using any spiders. Furthermore, scientists have no idea how the spiders incorporated the graphene into their silk, but if they were to insert graphene or other strengthening materials into their own artificial silk they would know exactly what they are working with.
Scientists are still working on incorporating molecules such as elastin into the silk, so it will be some time before silk-scaffolded synthetic organs or silken sutures become a reality. Buehler also cautions that while the silk backbone itself is compatible with the human body, the molecules added onto it may not be and must be tested to make sure that they do not cause harmful reactions. It was Spider-Man's Uncle Ben, after all, who said, "With great power, comes great responsibility."