New Tissue-Like Hydrogel Semiconductor is ‘a Significant Step in Material Design’

Published on Thursday, February 27, 2025

Researchers in the lab of UChicago Pritzker School of Engineering Assistant Professor Sihong Wang (left), including PhD student Yahao Dai (right), have developed a hydrogel that retains the semiconductive ability needed to transmit information between living tissue and machine, which can be used both in implantable medical devices and non-surgical applications. (Photo by John Zich)

Researchers at the University of Chicago have developed an entirely new material that functions both as a hydrogel and a semiconductor – overcoming longstanding challenges in bioelectronics.

With a significant water content, hydrogels are known for their mechanical and chemical similarity to biological tissues. Semiconductors conversely are dry and rigid, making them largely incompatible with biological environments, though essential for devices such as biosensors, pacemakers, and drug delivery systems.

“What we started to think is, how can we combine the design and all the benefits of a hydrogel with the properties of semiconductors,” said Sihong Wang, assistant professor of molecular engineering in the UChicago Pritzker School of Molecular Engineering, who has led a research team to address this question.

The answer, recently published in Science, lies in a new, patented method that incorporates water-insoluble polymer semiconductors into double-network hydrogels.

“This material development bridges the gap – or ‘mismatch’ – between conventional electronic materials, like silicon, and human tissue,” explained Wang. “This is a significant step in material design.”

The solvent affinity–induced assembly method produces a material that boasts a tissue-level modulus as soft as 81 kilopascals, alleviating immune reactions, a stretchability of 150% strain, and a charge-carrier mobility of up to 1.4 square centimeters per volt per second.

Unlike dense silicon, the material also features a high porosity that enhances molecular interactions at semiconductor-biofluid interfaces, resulting in photomodulation with higher response and volumetric biosensing with higher sensitivity. “The interactions that can be generated are not just on the surface,” explained Wang.

These properties together will lead to better brain-machine interfaces, pacemakers, biosensors, and more.

In creating something completely new, something never before seen, Wang notes the importance of being able to visualize the work. Having powerful imagery – something for which his lab is known – enables a better understanding of the unique attributes and where it could be useful.

“We are working toward a new type of human-electronic interface that provides much more efficient diagnosis for diseases and overall health monitoring as well as therapeutic effects.”

– Sihong Wang

The researchers have already shown that they can use light to produce electrical signals or heat for various therapeutic applications. The potential downstream technology use is broad – but Wang is most excited to explore its potential in biochemical sensing.

“Biology is a machinery of chemistry,” said Wang. “There are more than 500 different types of proteins. And how they interact and produce a response to different stimuli dictates how the different parts of the biological system work.”

Understanding these processes, however, is challenging.

“The implantable technologies to measuring chemicals, especially multiple types of chemicals at the same time, is very limited,” explained Wang, noting that there is “a huge amount of space and benefits to further develop.”

The patent is the latest in a series of inventions that together will enable tissue-like electronics that could seamlessly integrate with the human body for applications in health monitoring, medication therapy, implantable medical devices, biological studies, and more.

Exploring these use cases, Wang is currently collaborating with neurosurgeons at the University of Chicago Medical Center and testing prototype devices. He also is working with colleague Stacy Lindau, MD, MA ’02, a professor of obstetrics and gynecology and medicine-geriatrics and director of a research lab in the Biological Sciences Division to create a neural-prosthetic system that would be implanted underneath the skin of mastectomy patients. Called the Bionic Breast Project, the aim is to restore sensation to the breast area.

The group’s interdisciplinary approach is to address real-world problems outside of the lab. There are, of course, many needs, said Wang, but they are particularly interested in those challenges that are not easily solved.

“It’s not just about improving certain specifications of already existing technologies,” added Wang, “but creating a new technology that has never existed before.”

INTERESTED IN THIS TECHNOLOGY? Contact Harrison Paul, who can provide more detail, discuss the licensing process, and connect you with the inventor.

// Polsky Patented is a column highlighting research and inventions from University of Chicago faculty. For more information about available technologies, click here.