Here on the western side of one of the largest research universities in the country, Melik Demirel is performing magic.
Just add water, a bit of pressure and presto — the rip in your shirt is fixed. But Demirel, a professor of materials science and mechanics at Penn State, has far bigger designs than tailoring for the Hulk’s jorts or Wolverine’s active-wear line.
Yet the possibilities, which he says stretch across numerous disciplines, seem superhuman.
“So, you know, magic,” he said, smiling.
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Demirel and his team have found a way to take materials found in nature, known as the field of biomimetics, and synthesize them into self-healing textiles. Their crucible, a reactor analogous to those used in the fermentation process for alcohol, churns out a Nutella-like paste teeming with bacteria.
But these bacteria are special. Once purified through urease and enzymes, they produce a protein tinkered to the exact specifications of its maker. The process is reversible: If the team needs the material to be elastic, voila — Gumby-like get-ups are reality. The same holds true if the material is required to be brittle or divest itself easily, as is the case with DNA swabs where more cells can be transferred accurately and safely when covered in the secret sauce.
Eventually a liquid coating is produced; the trick lies here, rather than in the fibers themselves.
“If you use the material by itself, it’s a costly material,” Demirel said. “The idea came: How can we make it cheaper? Well, if you make a coating, then it’s much cheaper, because in a coating you are maybe using 1,000 times less material than if you’re using the bulk of the material.”
Once dipped in the magic brew, the fabric adopts self-healing properties, thanks to a similar protein found in squid tentacles. Through evolution, squid have developed teeth inside their suction cups, which contain the structural protein Demirel and his team are looking for. It’s the perfect analogue for their deus-ex-machina solution.
“With the synthetic one, you don’t have to stay with what nature provided you in the gene,” Demirel said. “So now we designed genes that are completely new — doesn’t exist in nature — therefore we can control its mechanical properties.
“The way we can do that is because we can play with the genes that are making the protein.”
The research, funded by the Army Research Office and the Office of Naval Research, has applications confined only by, on the self-healing surface, one’s imagination. In one test, Demirel’s team compared two strawberries — one with the coating and one without. After a week, one had rotted and the other stayed fresh.
“No, this works!” he said, laughing. “I think one sample was sitting there for the last two, three months, nothing happens ... and it is edible because squid is edible.”
Demirel, who will head a recently announced center devoted to advanced fiber technologies at Penn State, has never heard of Willy Wonka. He doesn’t have to: Life, in his case, has imitated art.
From biodegradable, edible packaging to protecting crops to potentially self-healing electronics, the possibilities seem as malleable as the material itself.
But back at the lab, Demirel’s mind is whirring again. He said there are much bigger squids to fry — or applications that are even more viscerally arresting and far-reaching than self-healing textiles.
Still, there may be one question that will continue to elude him.
“I don’t know why, but society has a very interesting appetite for self-healing,” he said, laughing. “They like it for some reason; I never discovered it.”
Roger Van Scyoc: 814-231-4698, @rogervanscy