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MIT spin-out iWalk, bringing to market prosthetic foot, raises $15 million from General Catalyst and Sigma Partners

Posted by Scott Kirsner  January 11, 2011 04:53 PM

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iWalk, a Cambridge start-up that has spent the past five years working on an advanced prosthetic foot, raised an additional $15 million last month; the new funding should be announced later this week.

Participating in the company's third funding round are Boston-based Sigma Partners, General Catalyst Partners of Cambridge, and New York City-based WFD Ventures. Paul Flanagan of Sigma is iWalk's newest board member.

In total, iWalk has now raised nearly $40 million.

The company was founded by Hugh Herr, an MIT Media Lab professor who is himself a double amputee; as iWalk has developed successive iterations of its "PowerFoot" device, few people have worn it as long as Herr.

As an individual wearing the PowerFoot walks, the device reacts to the environment, whether that's stairs or a ramp or level ground. The built-in sensors and microprocessors enable the PowerFoot to mimic the natural way that the foot, ankle, Achilles tendon, and calf muscle work together, storing and releasing energy (using an actuator and spring assembly.) Inside the PowerFoot is a lithium polymer battery that needs to be recharged daily. The PowerFoot weighs just 4.5 pounds, which the company says is equal in weight to the one you were born with (or a little lighter), assuming you weigh between 170 and 250 pounds.

iWalk CEO Tim McCarthy says the company will deliver its first five "commercial" PowerFoot devices (PowerFeet?) to the Walter Reed Army Medical Center in Washington, D.C. later this week. McCarthy moved to Boston in December 2009 to join iWalk; he'd previously headed sales and marketing for the American division of a big prosthetics maker, Ossur, in southern California.

Earlier in his career, Herr developed a prosthetic knee for Ossur, which is headquartered in Iceland.

Here's a company-produced video featuring retired Army staff sergeant Justin Lynn, a veteran of the Iraq war, talking about the iWalk's natural feel; it includes some amazing shots of Lynn walking up stairs at a construction site and playing golf.

You'll find more company videos here.

"We typically stay away from things that require FDA approval," says Flanagan of Sigma, "and their product has an exemption from that. So that put it into the playing field for Sigma. I talked to twenty soldiers and other people who've used the device, and the feedback on the product every single time was amazing." Flanagan says Sigma's investment rationale was based, unfortunately, on the number of amputations that take place in the U.S. annually (many are veterans injured in the line of duty, or patients who lose a leg and foot to diabetes.) But iWalk will likely offer other prosthetic devices in the future, and perhaps also wearable exoskeletons for those who today rely on leg braces.

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Innovation and technology news that matters, on a new website from the Boston Globe, featuring Scott Kirsner and other original reporting.

About Scott Kirsner

Scott Kirsner was part of the team that launched in 1995, and has been writing a column for the Globe since 2000. His work has also appeared in Wired, Fast Company, The New York Times, BusinessWeek, Newsweek, and Variety. Scott is also the author of the books "Fans, Friends & Followers" and "Inventing the Movies," was the editor of "The Convergence Guide: Life Sciences in New England," and was a contributor to "The Good City: Writers Explore 21st Century Boston." Scott also helps organize several local events on entrepreneurship, including the Nantucket Conference and Future Forward. Here's some background on how Scott decides what to cover, and how to pitch him a story idea.

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