Batteries add weight, and they need recharging. That’s serious business for implanted medical devices. When the batteries die, patients sometimes have to undergo another surgery. But what if there were a compact, flexible material that could harvest energy from the body’s own movement? That’s what Michael McAlpine’s lab at Princeton University designed. He was recently named to Technology Review's list of 35 top innovators under the age of 35.
The key is a novel form of piezoelectric materials. These become electrically polarized when they’re subject to mechanical stress, and so movement or pressure can generate electricity. But they’re ordinarily made of hard, inflexible materials, which are also usually toxic.
So McAlpine’s team created nanoscale piezoelectric devices. They’re sequestered between layers of silicone. Which, as we know from breast implants, is both flexible and biocompatible.
At a recent talk, McAlpine said that one of the first commercial uses could be to replace batteries in kids’ LED-lit sneakers. But he hopes to see them one day power pacemakers. They could be implanted on the lungs. And so, to keep your heart beating, you’d just take a breath. Which is the usual procedure.
—Cynthia Graber
