New Faculty Member Xiaoyue Ni

Xiaoyue Ni, an expert in digital health devices at the interface between micro/nanomechanics, bio-integrated electronics and artificial intelligence (AI), will join Duke’s Department of Mechanical Engineering & Materials Science (MEMS) beginning November 1, 2020. She also will have a part-time appointment in the Duke School of Medicine’s Department of Biostatistics & Bioinformatics.

With her focus on developing human-centered materials intelligence—that is, materials that can sense a human signal, transform and then adapt according to human actions or status—Ni will be part of the vibrant community of Duke engineers designing smart biomaterials and wearable technology for use in diagnostics, treatment and monitoring of human health.

“My passion is in mechanical behavior of materials, precision measurement and smart structures.” 

Xiaoyue NI, Assistant Professor of Mechanical Engineering & Materials Science and Biostatistics & Bioinformatics

Ni comes to Duke from the Querrey Simpson Institute for Bioelectronics at Northwestern University, where she worked as a postdoctoral researcher in the lab of John A. Rogers, a world-renowned bioelectronics pioneer. There, she developed a wireless wearable device for continuous, noninvasive monitoring of human body mechanics and tissue-level diagnosis that she will continue to refine in her new role at Duke.

The project incorporates mechanics and acoustics to comfortably and seamlessly capture signals that reflect bioactivities in the body, as well as signal processing and AI algorithms to tease out important biometrics from “noise”—for example, detecting the “super tiny ripples” of a pulse while a person is running and jumping, Ni said.

Since April 2020, she has worked on a project using the technology to monitor symptoms of hospitalized patients with COVID-19. 

The wireless device, made of serpentine interconnected circuits and soft polymer encapsulation that attaches to the skin of a patient’s suprasternal notch (the anatomical location at the base of the throat directly above the breastbone), contains a sensor that acts like a digital stethoscope. It counts coughs, measures how hard and loud they are and listens to other vital body sounds, like heartbeat and respiration patterns. It has the potential to even distinguish between a “dry” or “wet” cough and detect differences in the source of the cough deeper into the lungs that signal worsening of disease.

Ni also intends to explore the use of these sensors to probe tissue mechanics—for example, to assess and monitor muscle stiffness using multiple geosensors on the skin.

"It's like seismology, but on the surface of the body," she said.

In addition to these epidermal electronics, Ni focuses on developing programmable matter—creating advanced metastructures for active and smart materials.

“During my PhD, I worked on metals and studied the complex deformation microstructures in natural, single crystalline materials like copper,” she said. “I try now to make artificial lattices and defects that I can fully control and play with. Letting the ‘robotic’ microstructures evolve following designed mechanisms will provide us rich insights for creating novel intelligent materials that can have varieties of unconventional mechanical capabilities.”

Ni’s quest for these new materials relate directly to the biomedical aspect of her research, she says, because it provides ways to engineer materials that closely mimic mechanics of the human body or their functions.

Ultimately, Ni said, these will help improve the performance of wearable sensors by providing feedback to inform the design of the flexible electronics and biomaterials. Some “smart” materials could even morph or adapt themselves to different positions of the body, for example, a necessary feature for consistent data collection and the patient’s comfort.

“My passion is in mechanical behavior of materials, precision measurement and smart structures,” she said. “I was attracted to Duke in part because I really like how the whole MEMS department appreciates and pursues the fundamental aspects of mechanics and materials science.”