Yamin Zhang

Temporary pacemakers help the heart maintain a steady beat following surgery but come with significant drawbacks. The devices, which consist of a heart-stimulating electrode and a source of power, are clunky—inserting them entails running a wire through a vein or through the wall of the chest. Because the body forms scar tissue around foreign objects, removing the wires when they’re no longer needed is a risky procedure that can sometimes cause tears in the heart or lead to infections.

Yamin Zhang, 32, invented a new type of pacemaker that’s far less invasive. Her wireless, self-powered contraption, which she developed as a postdoctoral researcher at Northwestern University, sits directly on the heart and naturally degrades in the body. 

The device is both an electrical stimulator and a battery: Its electrodes, made from bioabsorbable metals like molybdenum, magnesium, and/or zinc, pass current through the heart’s own fluids, which serve as the battery’s electrolyte. The pacemaker, roughly the size of a sesame seed, can be turned on or off with a light source attached to the patient’s chest. It’s small enough to be injected into the body and is also well-suited for young children, who are at greatest risk of complications from conventional devices.

Zhang’s design, which was detailed in a 2025 paper in Nature, has been tested in several types of mammals as well as on human hearts from organ donors. The next step will be clinical trials with human patients. In addition to reinventing the pacemaker, her advances in self-powered electrical stimulation could also help block pain, heal wounds, and regenerate tissue after a burn.