Artificial ‘leaf’ powers wireless biomedical device

Plants convert light into energy efficiently through photosynthesis—an ability that scientists and engineers still struggle to match with electronic devices. 

Recently, researchers have looked beyond traditional semiconductor materials to create devices using a promising class of materials called nanoplasmonics. These tiny metal structures can absorb and concentrate optical energy and generate energetic charge carriers.

In a new study, researchers from the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and Department of Chemistry developed a nanoplasmonic “leaf,” a wireless bioelectronic device that they used to stimulate nerves and pace heartbeats in an animal model. 

The team also showed that their material could be used as a computer-like sensing platform, where users can interact with the screen using invisible light—a potentially secure way to transmit information. 

“These materials are very unique and are different from other light-sensitive devices, like photovoltaics,” said Pengju Li, a former UChicago PME graduate student who is now a postdoctoral fellow at Princeton University. “Through our design, we have increased these nanostructures’ ability to store energy, so now they can potentially be used as new forms of therapy and in new human-computer interfaces.”

The research, published in Nature Photonics, was led by the lab of UChicago chemistry professor Bozhi Tian and included researchers from across UChicago, Seoul National University, Brookhaven National Laboratory, and Argonne National Laboratory.

A new kind of bioelectronic

Current light-harvesting devices, like solar cells, use semiconductor materials to convert sunlight into energy. But these materials have efficiency limits due to the laws of physics.

Nanoplasmonics could theoretically be more efficient. These materials are made from noble metals, like gold. The metal is combined with titanium dioxide into tiny nanostructures—about 15 nanometers in size—that absorb light. 

In these materials, light excites plasmons that decay into energetic electrons and holes. These electrons and holes, called hot carriers, allow researchers to manipulate electrical and chemical processes at the nano level. These structures essentially act as tiny light-powered energy converters, providing electrical energy without the need for wired power sources. 

But researchers needed to understand how to design and build these materials to amplify the electrical current from them. For years, Li worked on this problem until he discovered a new idea: a gold nanoparticle surrounded by a hemisphere of titanium dioxide, bottomed by a gold film. The structure absorbs the light, and the gold film acts as a mirror that reflects and amplifies the energy within.

“If you don’t have that gold layer, the light just passes through,” said Yuze Zheng, a co-first author of the paper and a graduate student in the Tian lab. “But having the film amplifies the performance of the material to make it useful for devices.”

After creating the material in UChicago’s Pritzker Nanofabrication Facility, the team tested it in a rat model. They placed a patch of material on the heart and demonstrated that they could control the pacing of the heart by shining light onto it. They also attached it to the sciatic nerve; when light was shined onto the material, it stimulated the nerve—demonstrating a potential therapy for nerve pain. 

The material has a performance level of milliamperes per square centimeter—a value that is considered very high for wireless systems. It is as high or higher than comparable semiconductor materials. 

“We haven’t seen any other nanoplasmonic device like this that can achieve this sort of performance and perform these useful bio-interface applications,” said Guangqing Yang, another of Tian’s graduate students and a co-first author of the paper.

The future of sensing and stimulation devices

To demonstrate the other possibilities of this material, the team also developed an optosensing platform. Similar to a touch screen, this pixel-less platform responds to light instead of touch. Researchers interacted with the screen using a laser pointer, then used an artificial intelligence program to reconstruct the patterns they had shone. 

“A device like this could change the way people interact with computers,” Li said. “Instead of using touch, you can use light to input certain information. And the light can be invisible, which would improve security. AI can then be used to decode what you wrote. This opens up new directions for our material.”

Next, the team is developing a fully implantable device that could be used for biostimulation for a year or longer. They also hope to develop similar platforms for quantum-based sensors. 

“What really makes research like this possible is a collaboration across different research areas,” Li said. “We work with biochemists and biophysicists, people who understand the quantum mechanics of these materials. That collaborative spirit is essential to PME, and it’s something that is really commendable.”

Citation: “Self-organized nanoplasmonic artificial leaf for hot-carrier bioelectronic interfaces.” Li et al. Nature Photonics, June 24, 2026. DOI: 10.1038/s41566-026-01949-5.

Funding: National Institutes of Health, National Science Foundation, Air Force Office of Scientific Research, US Army Research Office.