We all know about plaque from dreaded trips to the dentist. But plaque can also build up inside the arteries, taking the form of fatty deposits that can potentially restrict blood flow. Some deposits remain stable for years, while others accumulate and increase the likelihood of rupture. When this happens, a blood clot can cause a heart attack or stroke by blocking blood flow to the heart or the brain.
Helping physicians to distinguish dangerous, unstable plaque is the goal of a research project led by Hangbo Zhao, assistant professor of aerospace and mechanical engineering and biomedical engineering at the USC Viterbi School of Engineering. His work has earned a National Institutes of Health (NIH) Trailblazer Award from the National Institute of Biomedical Imaging and Bioengineering(NIBIB), which supports new and early-stage investigators who combine engineering, the physical sciences and the life sciences to tackle important biomedical challenges.
Zhao's project, "High-Resolution 3D Electrical Impedance Mapping of Metabolically Active Plaques Using Multilayered Stretchable Liquid Metal Electronics," uses electrical measurements to reveal features of arterial plaque that conventional imaging isn't able to capture. "Rather than replacing existing imaging technologies, the catheter is designed to provide physicians with additional information about plaque composition and metabolic activity," Zhao explained.
That approach builds on Zhao's broader research in micro and nanomanufacturing, soft electronics and soft robotics. Much of the work of his research group focuses on developing electronic systems that can bend, stretch and conform to soft biological tissues
Blood vessels present a particularly demanding engineering challenge because they are soft, curved and constantly in motion, while the electronics inside most medical devices remain rigid."
Hangbo Zhao, assistant professor of aerospace and mechanical engineering and biomedical engineering, USC Viterbi School of Engineering
His group addresses that mismatch by developing mechanics-driven manufacturing techniques that fabricate multilayered stretchable circuits from liquid metal, allowing the sensing surface to conform closely to the artery while maintaining reliable electrical performance.
"I'm thrilled by this award because it enables us to translate our advances in soft electronics manufacturing into next-generation surgical tools," Zhao said.
The stretchable electronics are integrated onto a balloon catheter that can be threaded through narrow arteries in a compact configuration. Once the catheter reaches the target site, the balloon is gently inflated so the electronics make close, uniform contact with the vessel wall. This close contact is essential for obtaining consistent electrical measurements around the artery, allowing the device to create a three-dimensional map that could help physicians identify plaque at greater risk of rupture.
The award will also support a collaboration with Tzung Hsiai, professor of medicine and bioengineering at UCLA. Together, the two research groups will evaluate the technology in animal models of cardiovascular disease, providing an important opportunity to assess how the device performs under physiologically realistic conditions.
"The NIH Trailblazer Award represents a unique opportunity to bridge engineering and the life sciences," said Zhao. "This project has the potential to enable significant medical advances by introducing flexible devices that seamlessly integrate with living tissue."
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