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“Fantastic Voyage”-inspired Chip Is Made To Move

Stanford researchers present a way to move chips through the body using magnetic fields

2 min read
“Fantastic Voyage”-inspired Chip Is Made To Move

For a number of basic physics reasons, the world of the 1960’s movie Fantastic Voyage will always remain out of reach. We won’t ever shrink humans and submarines down to microscopic sizes to perform medical interventions inside the human body.

But hasn’t stopped researchers from attempting to develop devices that could do much the same thing. Some have opted for pills that propel themselves with mechanical parts, like jarringly sharp insect-inspired legs or moving clamps that perform an inchworm crawl. Others are exploring more passive schemes that use magnetic fields to guide ferromagnetic objects through the bloodstream.

A team led by Ada Poon of Stanford University has devised a different approach. After convincing themselves that ultra-small wireless antennas can receive a fair amount of power even after transmissions pass through human tissue, Poon and colleagues built a 3 mm x 4 mm prototype chip that exploits an external magnetic field to actively propel and steer itself.

The chip harnesses the Lorentz force, the force that arises when an electric charge moves in a magnetic field. One scheme (illustrated above) uses electrodes at the rear of the chip to run a current through a fluid. The other uses a loop of wire attached to the chip. Alternating the direction of current in the loop will allow the chip to wiggle itself forward by virtue of asymmetric drag.

Experimenting in water, Poon’s team found they could propel the chip at speeds of 0.53 centimeters per second with a magnetic field that’s about 1% as strong as the field in an MRI. Stanford graduate student Anatoly Yakovlev presented the chip designs on Tuesday at the IEEE International Solid-State Circuits Conference in San Francisco, Calif.

Poon says this approach to locomotion requires less energy and will be easier to miniaturize than mechanical locomotion. And unlike approaches that use passive magnetic materials, Poon says her team's current propulsion schemes shouldn’t need strong or complex magnetic fields to work. At its present size, she says the chip is suitable for the stomach or digestive track and perhaps the larger vessels of the body’s venous system.

Attendees of Yakovlev’s talk brought up a few safety concerns, including the possibility that the chip’s electrodes could create unwanted chemical reactions. But Poon says careful selection of electrode materials will cut down on that risk and that the biggest foreseeable danger is that the device might get lost as it’s guided through the body. This is unlikely to be much of an issue in the digestive system, but “for motion through the blood stream, the danger is much higher because the device must be removed after use,” Poon says. She says adding feedback control to the chip to assist with navigation might help prevent an operator from losing the device.

Poon says that it should be fairly straightforward to shrink down the device and lists drug delivery and diagnostic imaging and sensing as potential applications. But we’re still a far way from Richard Feynman’s “swallow the surgeon” vision of the future or even in vivo tests of the device. In the short term, Poon says the locomotion schemes the team has devised could help improve existing medical equipment, by, for example, helping guide the tips of catheters used in cardiovascular surgery.

Image courtesy of Ada Poon

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Are You Ready for Workplace Brain Scanning?

Extracting and using brain data will make workers happier and more productive, backers say

11 min read
A photo collage showing a man wearing a eeg headset while looking at a computer screen.
Nadia Radic

Get ready: Neurotechnology is coming to the workplace. Neural sensors are now reliable and affordable enough to support commercial pilot projects that extract productivity-enhancing data from workers’ brains. These projects aren’t confined to specialized workplaces; they’re also happening in offices, factories, farms, and airports. The companies and people behind these neurotech devices are certain that they will improve our lives. But there are serious questions about whether work should be organized around certain functions of the brain, rather than the person as a whole.

To be clear, the kind of neurotech that’s currently available is nowhere close to reading minds. Sensors detect electrical activity across different areas of the brain, and the patterns in that activity can be broadly correlated with different feelings or physiological responses, such as stress, focus, or a reaction to external stimuli. These data can be exploited to make workers more efficient—and, proponents of the technology say, to make them happier. Two of the most interesting innovators in this field are the Israel-based startup InnerEye, which aims to give workers superhuman abilities, and Emotiv, a Silicon Valley neurotech company that’s bringing a brain-tracking wearable to office workers, including those working remotely.

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