Sound waves can enable us to see things that would otherwise be invisible.
And that’s thanks to acoustics—the field that covers all aspects of how mechanical waves travel through solids, liquids and gases. For example, it’s key in the sensing technology sonar, which submarines use to map out underwater hazards, and acoustics enables ultrasound scanners to render a developing fetus in utero.
“Ultrasound has become one of the most important imaging and diagnosing methods in biomedicine,” says Chu Ma, who joined the Department of Electrical and Computer Engineering at the University of Wisconsin-Madison as an assistant professor in fall 2019.
Even astronauts aboard the International Space Station use ultrasound to monitor the health of their organs; in fact, the technology is the only medical imaging method that is sufficiently small, portable and safe to bring up into near-earth orbit and produces a real-time image that can be transmitted to doctors on earth.
Even beyond using sound waves to peer inside the body and diagnose disease, acoustics is opening up new frontiers in treatment.
“Acoustics can be used to manipulate cells and tissues in the human body,” says Ma. “There are so many useful applications being developed for cancer treatment and drug delivery.”
Ma works primarily on acoustic sensing, the technology behind ultrasound.
Even though ultrasound has advanced considerably, Ma has her sights even higher for what acoustic sensing can achieve.
Ma’s research draws from physics, materials science, electronics and information engineering to allow her to develop sensing systems that can resolve small objects with pinpoint accurate resolution. She also works closely with clinicians and biological engineers to implement acoustic sensing systems in medical settings.
That’s why UW-Madison’s low barriers to working across traditionally disparate fields attracted Ma to the College of Engineering. As a fellow of the Grainger Institute for Engineering, she’ll also have ample opportunities for cross-disciplinary collaboration.
“My research is very interdisciplinary, and UW-Madison makes interdisciplinary collaboration very easy,” says Ma.
During her PhD work at the Massachusetts Institute of Technology, Ma developed an acoustic sensing system able to detect objects smaller than the diffraction limit—which is a fundamental threshold that constrains the resolution of all sensing systems.
In order to get around the diffraction limit, Ma needed materials with properties not normally found in nature, which is why she used 3D printing to create a composite substance called a metamaterial with advanced acoustic abilities.
She also worked to develop metamaterials based on flexible hydrogels with custom-tunable properties that could be manipulated in real time, substantially improving the signal-to-noise ratio for the sensing systems.
At UW-Madison, Ma plans to continue her work on metamaterials and acoustic sensing. She’s looking forward to collaborating across campus, lending her expertise to projects that need reliable methods for noninvasive medical imaging, such as Biomedical Engineering Professor Justin Williams’ work on neural prosthetics.
“They need a reliable way to image the interface between implants and neurons,” says Ma. “Ultrasonic imaging is an ideal technique to track the junction.”
Author: Sam Million-Weaver