It all began with a dead shark and a $500,000 3-D printer.
Two years later, Harvard scientists say that they've managed to replicate one of the most fascinating organs of the animal kingdom in a lab. Their finely-detailed synthetic shark skin could make some of the fastest underwater robots around, and maybe even one day grace human wetsuits or the hulls of ships.
Biomimetics, the practice of building machines that mimic the natural world, has made enormous strides in the last handful of years. But while other research centers focus on speedy, galumphing land robots, or super-precise aerial drones, Harvard evolutionary biologist George Lauder's domain is the sea. For the past 15 years, he's been building robots that resemble fish.
Lauder describes building synthetic parts like shark skin as something of a recent cottage industry. But in order to improve on natural tricks, first, his team had to learn how shark skin really worked. "You're stuck with what the shark gives you, if you will," he says. "Really, in brief, our goal was just being able to design something we could change."
So how did they start? "We went down the fish market, bought a bunch of sharks, and brought them back here to Harvard," Lauder says.
From there, Lauder and his students put shark skin through a number of tests in an experimental tank—something like a fish treadmill, as Lauder puts it. They made a flag of shark skin pieces, attached them to motors and computers, and saw how they functioned. Shark skin, they found, reduced drag and increased energy efficiency by as much as 6%.
Two years later, after a lot of trial and error, Lauder and his team have replicated the tiny jagged scales and the flexible skin they're embedded in through a single multi-material printer. With that breakthrough, researchers say they have an opportunity to improve on nature's design. Still, because the manufacturing challenges were so great, it's unlikely we'll start seeing mass-produced shark skin on bikinis any time soon.
"If you could make a human wetsuit that had the surface structures we had for this paper, you would greatly improve swimming performance," Lauder said. "[But] I think the main application in the future might just be reducing the cost of swimming in bio-inspired fish robots."