Nano-Subs Grab and Move Oil Spills

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Remaining crude oil from the Exxon Valdez oil spill contaminating the beach surface in 1991, years after the spill.
Corbis

THE GIST

- Microsubmarines could pick up and move droplets of oil away from contaminated waters.

- The devices are about 10 times thinner than a human hair.

Scientists say they have built a self-propelled "microsubmarine" that can scoop up oil from contaminated waters and take the droplets to a collection facility.

While environmental engineers have used bacterial dispersant to break down oil spills for decades and are developing genetically modified organisms to "eat" oil, this would be the first controllable spill-buster.

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"These are autonomous self-propelled motors," said Joseph Wang, distinguished professor of nano-engineering at the University of California, San Diego. "You can guide them back and forth to remove oil. It's the first example of using nano-machines for environmental remediation and has opened the door to a new direction."

The study by Wang and Maria Guix of the Catalan Institute of Nanotechnology in Barcelona appears in the American Chemical Society journal ACS Nano. The project piggybacks off earlier experiments in the past few years in Wang's lab to build self-propelled devices to do DNA sampling and attack cancer cells in blood serum.

The new micro-subs have a special surface coating, which makes them "super-hydrophobic," or extremely water-repellent and oil-absorbent. This new coating was applied to one of the existing micro-devices that Wang's lab had already developed.

"It's like a big sub with a special coating," Wang said.

The cone-shaped subs are 10 times smaller than the width of a human hair, use chemicals for fuel, and in the experiments, collected droplets of olive oil and motor oil and transported them to another area. If successful, Wang says the micro-subs could be used to clean up massive oil spills, without harming marine or coastal habitats.

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The ultimate use for these devices could be found the 1966 sci-fi film 'Fantastic Voyage' in which a team of scientists (including Raquel Welch and Donald Pleasance) were put into a sub-like craft, shrunk and then injected into the human body to save a diplomat's life, according to Thomas Mallouk, director of the Center for Solar Nanomaterials at Pennsylvania State University.

"I saw it recently," Mallouk said about the ground-breaking, yet now-dated film. "It's a conceptually interesting idea for a minimally invasive device. That's one of the engineering applications we would like to ultimately be able to do."

Mallouk said Wang's lab has been a leader in identifying applications for the tiny micro-machines like the oil-grabbing sub.

Despite his successes, Wang said the project is still in the early stages and won't be ready to launch if there's another Deepwater Horizon spill anytime soon.

"It's not something that is ready to use yet," Wang said. "Now we have to address some practical challenges."