A doctor repairs a patient’s knee cartilage and bone using a 3D-printing process, driven by ultrasound, that occurs inside the patient’s body. And the procedure is minimally invasive. Xiao Kuang is developing soft (bio)materials and advanced manufacturing technologies that could enable such medical procedures in the future.
Situated at the intersection of materials, manufacturing and medicine, Kuang’s research extends to broad applications—including aerospace, soft robots, biomedical devices, drug delivery and tissue engineering—to solve societal challenges in sustainability and health. Kuang, who joined the University of Wisconsin-Madison Department of Mechanical Engineering as an assistant professor in August 2024, also will play a key role in the Polymer Engineering Center.
Using experiments, theoretical analysis and computational tools, Kuang studies how polymeric systems respond to stimuli such as heat, light, chemical, mechanical and acoustic fields. “I’m particularly interested in understanding how external stimuli interact with polymers at the molecular level and also at larger scales,” he says. “This interaction can trigger physical and chemical responses that could cause material construction/destruction, shape-changing, self-healing or growth.”
At UW-Madison, Kuang plans to especially focus on ultrasound as an external stimulus. That’s an area in which he is already a pioneer. Because ultrasound waves can penetrate into deep regions, such as thick biological tissues, Kuang created an innovative ultrasound printing technique called deep-penetration acoustic volumetric printing—and that enables 3D printing inside the body.
The technique involves a special kind of polymer ink that can be injected into the body; the ink responds to ultrasound by transforming from liquid to solid. Kuang and his collaborators also developed an ultrasound 3D printer using a focused ultrasound transducer so they could precisely focus the ultrasound waves. By combining these two technologies, Kuang focused the ultrasound energy to quickly solidify the polymer ink and build a custom structure inside of materials that scatter light—including under centimeters-thick tissue.
“Unlike other 3D-printing methods that build an object layer by layer and the prevalent light-based printing technique that needs optical transparent inks, our technique enables scanning and directly ‘writing’ inside the material to volumetrically build complex structures,” says Kuang, who detailed the new technique in a paper published in the journal Science in December 2023.
At UW-Madison, he will develop characterization platforms that will allow him to gain a better fundamental understanding of the interaction between polymer composites and ultrasound. In combination with theoretical and computational tools, he will use this knowledge to guide the design of ultrasound-responsive polymeric systems and the development of new acoustic manufacturing techniques with imaging-assisted adaptive control for both engineering and medical applications.
Kuang earned his PhD in polymer chemistry and physics from the University of Chinese Academy of Sciences in 2016. He worked as a postdoctoral researcher at Georgia Institute of Technology and Brigham and Women’s Hospital & Harvard Medical School before joining UW-Madison.
He says UW-Madison is an ideal place to pursue his research, given its world-class facilities, longstanding excellence in polymer engineering research and education, and support for interdisciplinary research collaborations.
“The university also has a very strong medical school, and I’m excited to collaborate with researchers there to develop biomaterials that can be used for in vivo printing,” he says. “I want to pursue interdisciplinary collaborations to bridge from engineering to medicine and to ultimately help benefit human health.”
Photo of Xiao Kuang by Joel Hallberg