When Guangqing Yang watches light dance across the tiny structures in her lab at the University of Chicago, she sees something that could one day ease human suffering. Working in Professor Bozhi Tian's laboratory, Yang and her teammates have built an artificial leaf no larger than 15 nanometers that can stimulate nerves and pace a heart using nothing but light.
The device, described in a new study published in Nature Photonics, represents a fundamental shift in how we might power the next generation of medical implants. Unlike traditional solar cells that convert light into electricity, these nanoplasmonic materials—made from tiny gold nanoparticles wrapped in titanium dioxide—can store energy and release it on demand to control living tissue wirelessly.
"We haven't seen any other nanoplasmonic device like this that can achieve this sort of performance and perform these useful bio-interface applications," Yang said.
The team tested their creation in living rats. When they placed a patch of the material on a heart and shone light through the skin, they controlled the organ's beating. In a separate test, attaching the device to the sciatic nerve and illuminating it soothed nerve activity—a discovery that hints at future therapies for chronic pain.
Pengju Li, a former graduate student in the Tian lab who now leads research at Princeton University, spent years figuring out how to amplify the electrical current these tiny structures produce. His breakthrough came through an elegant design: a gold nanoparticle surrounded by a titanium dioxide hemisphere, backed by a gold film that acts like a mirror to trap and magnify incoming light.
"If you don't have that gold layer, the light just passes through," explained Yuze Zheng, another graduate student and co-first author of the paper. "But having the film amplifies the performance of the material to make it useful for devices."
The material achieves performance levels measured in milliamperes per square centimeter—considered exceptionally high for wireless systems and competitive with or exceeding comparable semiconductor technologies.
Beyond medicine, the team demonstrated that the same principles could create computer interfaces controlled by invisible light, opening possibilities for secure information systems. As these materials move from rat experiments toward human applications, they offer a vision of medical devices that need no batteries, no wires, and leave no scars.