“It’s really a superhero-inspired material.”
Heroic Act
Researchers say they’ve created real-life web-slinging technology like something straight out of “Spider-Man.” Their prototype won’t have you swinging from buildings anytime soon, but it does nail the gist of Peter Parker’s nifty gizmo.
As detailed in a new study published in the journal Advanced Functional Materials, researchers developed a specialized fluid that when ejected from a needle, immediately solidifies into a string that clings to objects. It’s also strong enough — and sticky enough — to lift them.
While spiders remain the masters of silk-weaving, this device can do one thing that most arachnids can’t: shoot their web, according to study coauthor Marco Lo Presti.
“We are demonstrating a way to shoot a fiber from a device, then adhere to and pick up an object from a distance,” Lo Presti, a biomedical engineering researcher at Tufts University, said in a statement. “Rather than presenting this work as a bio-inspired material, it’s really a superhero-inspired material.”
Brainy Solution
The researchers’ fiber is primarily made of a solution containing silk fibroin, a protein building block that’s derived from boiling down the silk produced by moth cocoons. Silk fibroin on its own can form a stringy adhesive, but to figure out how to make it solidify mid-air, the researchers needed a lucky break.
“I was working on a project making extremely strong adhesives using silk fibroin, and while I was cleaning my glassware with acetone, I noticed a web-like material forming on the bottom of the glass,” Lo Presti said in the statement.
The researcher realized that a combination of acetone and dopamine — yes, that same feel-good chemical produced by your brain — accelerated the solidification process from taking hours to occurring almost instantly.
Along with being inherently adhesive, the dopamine in particular appeared to dramatically speed up the process by extracting water out of the silk fibroin, while the acetone evaporated.
Strung Along
That solved the web-shooting part. To strengthen the fibers, though, the researchers added a material called chitosan, a sugar biopolymer derived from the chitin that forms insect exoskeletons. They also added borate ions to make it even stickier.
With all that fine-tuning, the fibers could pick up objects over 80 times their own weight at a distance of around five inches. As seen in one video demonstration, the web-slinging device successfully plucks out a metal scalpel stuck in a petri dish of sand, after capturing it with a stream of snot-like goop that quickly hardens.
It’s not as elegant as how a spider would do it, and the incredibly strong silk that spiders produce is still about 1,000 times stronger than the researchers’ artificial fibers. Still, even if the researchers fell short of matching up to nature’s silk-savants, imitating a superhero’s gimmick is nothing to sneeze at.
“We can be inspired by nature. We can be inspired by comics and science fiction,” said coauthor Fiorenzo Omenetto, director of Tufts’ Silklab, in a statement. “In this case, we wanted to reverse engineer our silk material to behave the way nature originally designed it, and comic book writers imagined it.”
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