This New Shock-Absorbing Gel Can Withstand Supersonic Impacts

Made from a resilient protein in human cells, the technology could improve body armor, space gear and even cell phone cases

a shattered smartphone
The new hydrogel might someday lead to shock-absorbing smartphone cases, as well as better bullet-proof vests and space equipment. Marco Verch Professional Photographer via Flickr under CC BY 2.0

Existing body armor can stop shrapnel and bullets from reaching the person wearing it. But it doesn’t absorb a projectile’s kinetic energy, meaning the wearer can still get injured from the force of the blow. Beyond that, most body armor—made from heavy, bulky layers of ceramic and fibers—is only good once, as a strike from a projectile can compromise its structural integrity.

Now, researchers at the University of Kent in England may have developed a promising new solution to these problems, providing a potential path forward for improved bullet-proof clothing and more resilient space exploration equipment. Using a protein called talin, which is found in human cells, scientists have created a novel material that can absorb the impact of projectiles—even those flying faster than the speed of sound.

Talin helps cells get around inside the body and may also play a role in memory storage. But notably, it acts as a “natural shock absorber,” says lead researcher Benjamin Goult, a biochemist at the University of Kent, in a statement.

Talin molecules contain structures that, when put under tension, unfold and stretch out. Once the tension is released, they fold back up again. They can do this shock-absorbing maneuver over and over without harming the cell.

By adapting the talin molecule and linking large numbers of them together, the researchers created a gel-like material called a hydrogel that maintained the natural protein’s shock-absorbing properties.

“Mother Nature is an amazing designer, and it’s always interesting when scientists and engineers can find new applications for structures that are everywhere around us,” Eric S. Hintz, a historian at the Lemelson Center for the Study of Invention and Innovation at Smithsonian’s National Museum of American History who was not involved in the project, tells Smithsonian magazine in an email. The new hydrogel, he says, “sounds very promising.”

To test the technology’s effectiveness, scientists placed the gel atop an aluminum plate and fired tiny basalt particles and larger bits of aluminum at it. These small projectiles traveled at speeds of more than 3,350 miles per hour—three times faster than a bullet fired from a handgun, as Andrew Liszewski notes for Gizmodo. The hydrogel absorbed the shock of the projectiles, successfully protected the aluminum plate and captured the particles without destroying them.

The team ran the same experiment with a control gel. When pelted with a supersonic particle, the control gel allowed it to pass through and bore a crater in the aluminum plate behind the gel. The projectile was also destroyed in the process. The researchers published their findings on the preprint server bioRxiv; the paper has not yet been peer-reviewed.

“Our material perfectly caught and ‘cuddled’ with the projectile … keeping it beautifully preserved,” says paper co-author Jennifer Hiscock, a supramolecular chemist at the University of Kent, to New Scientist’s Carissa Wong.

The researchers patented the material and are now conducting even more tests with partners in the aerospace and defense industries. Talin may someday help protect soldiers heading into battle and spacecraft traveling through fast-moving dust and debris in space.

In the realm of body armor, one of the talin gel’s strengths is that it can stop a bullet without destroying it, Hintz says. “You can imagine how important this would be for law enforcement officers, who could remove the preserved bullet from a [talin] vest, then run forensics to match the bullet to the shooter’s gun,” he says. “In addition, the … material reforms after initial impact, meaning you could potentially reuse a [talin] vest after it was hit.”

As for aerospace, the industry currently uses aerogels, or low-density gels that had the liquid removed from them, to capture flying projectiles. Aerogels achieve this, in part, by turning the projectile’s energy into heat. “This can melt the aerogel itself, rendering it useless for the next impact,” Hintz says. “It appears that the [talin materials] do not heat up as much. So … a [talin]-based outer layer on a spaceship would potentially remain intact, even after multiple high-speed strikes from micro-meteorites or space debris. That would make astronauts feel more confident in the structural integrity of their spacecraft.”

The new material may also be useful for capturing space debris—without destroying it—for further study.

Consumers may also one day reap the shock-absorbing benefits of talin in their running shoes, vehicle bumpers and cell phone cases, reports IFLScience’s Laura Simmons.