UMass engineers develop battery-free mesh that harvests power from human cells

Every implantable medical device that keeps someone alive—a pacemaker, a cochlear implant, a deep brain stimulator—carries the same fundamental problem: it needs power, and the only answer we have had for decades is a battery that will eventually die. Engineers at the University of Massachusetts Amherst have now designed a way around that constraint entirely. They built an ultrathin, flexible mesh that grows directly into human tissue and harvests electrical power from the cells themselves, eliminating the need for any battery at all.

The work, published in Science Advances, emerged from a simple observation about how the body actually works. Unlike any machine we build, which relies on a centralized power source feeding energy outward, the human body operates as a distributed network. Each cell is its own power plant. Some of that power is electrical—the impulses that fire through nerves—and some is mechanical, the contraction of muscle tissue. Jun Yao, an associate professor in the engineering college at UMass Amherst and the paper's senior author, recognized that if you could tap into that cellular power directly, you would never need to replace a battery again.

The team started with thin ribbons of lead zirconate titanate, a material known as PZT that converts mechanical energy into electrical current. They bonded these ribbons onto an ultrathin, ultraflexible polymer base, creating a platform that could move and flex like living tissue. Then they seeded the platform with human cardiac cells. As those cells grew, they wove themselves seamlessly into and around the PZT material, creating a hybrid device that looked and moved like tissue but functioned as a self-renewing power source.

The results were striking. The mesh generated ten times more power density—the amount of energy produced per unit volume—than systems that rely on a single centralized battery. That advantage comes from the distributed nature of the design itself. Because the films are so thin, they can be stacked in layers, multiplying the power output without adding bulk or invasiveness. A device that sits at the cellular level, Yao notes, faces far less biological rejection than one that arrives as a foreign object with a bulky battery pack attached.

Yao is careful to emphasize that this work remains in the laboratory stage. The team has not yet moved toward human trials or clinical application. But the principle is proven: a device can exist at the scale of tissue itself, harvest energy from the cells around it, and do so in a way that the body accepts rather than fights. For patients who depend on implanted electronics to survive or function, the difference between a device that needs replacement surgery every few years and one that never needs a new battery could be transformative. The research points toward a future where the boundary between medical device and living tissue becomes not just thinner but nearly invisible.