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UW-Madison Graduate student Guang Yao and Professor Xudong Wang show off their new implantable device.

University of Wisconsin-Madison researchers may have come up with a new solution for treating morbid obesity: A small device that, when surgically attached onto a person’s stomach, can make someone feel more full after eating.

A nanotechnology and nanoscience research team led by the material sciences and engineering professor Xudong Wang published research in December in the journal Nature Communications asserting that rats implanted with their patented device lost 35 percent of their body weight within 18 days. And while the technology is a long way from hitting the market, Wang said he’s eager to take steps toward commercialization as soon as possible. He said he’s been receiving dozens of emails from people asking to become part of a clinical trial.

“I’m very sorry that we’re far from that point,” he said. “It puts some pressure on us  — I want to move on this.”

The device itself comprises a tiny nanogenerator embedded on a flexible foundation of polymers, all of which can be attached to the lining of a person's stomach. 

The idea, said Wang, is that the patch responds to movements of the stomach. The natural constrictions of the stomach “squeezes” the device, he said, which generates electricity. The patch sends pulses to the vagus nerve, one of the primary neurological channels for controlling hunger. Those pulses are a signal that tell the brain, “stop eating,” said Wang.

Wang said that the implant is an alternative to other surgical treatments for morbid obesity, such as the gastric bypass, which alters the stomach and small intestine for the purposes of weight loss. Whereas the bypass is irreversible, his team’s device can be taken out of a patient if they so desire.

“If you remove it things go back to normal,” said Wang. “It has minimal alterations to our body.”

Wang’s is not the first implantable device that “neuromodulates” weight loss. A company called EnteroMedics received Food and Drug Administration approval for a device called VBloc in 2015. Researchers have reported that the device, which blocks signals to the vagal nerves, resulted in “medically meaningful weight loss” among human patients in a two-year trial.

However, Wang said there are key differences between Vbloc and the device his team has engineered.

“Our device is much smaller, and much simpler,” he said. “Our device is flexible...It makes more comfortable contact with the stomach’s surface.”

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A big reason for the difference in size is the fact that whereas the Vbloc uses a battery, like a pacemaker, Wang’s device strictly relies on triboelectric generation — in other words, electrification due to friction, without the need of a battery.

Also, because the electricity generation is entirely self-activated, there are no external controls for patients to use, as they would have with Vbloc. Wang said he sees that as an upside — the device is on autopilot, with no need for patients to think about any sort of inputs.

Wang’s neurotechnology team has been working on renewable and implantable devices for about 10 years. Lately, he said, the focus of his group has been on the electrical impulses that control biological functions. He said that it’s possible that in the coming years, other researchers in the area will help advance implantable technology.

“There are not a whole lot of implantable devices at this point, but it’s a very active research area,” he said.

Thus far, Wang said he’s not aware of any negative side affects or major risks to his implantable device, although he noted that research on the technology is still early, and human tests are a ways away. The next step, he said, will be to test the implant on an animal with more similarities to a human, such as a pig.

Erik Lorenzsonn is the Capital Times' tech and culture reporter. He joined the team in 2016, after having served as an online editor for Wisconsin Public Radio and having written for publications like The Progressive Magazine and The Poughkeepsie Journal.