Wireless Patch Measures Tissue Stiffness for Real-Time Health Monitoring

Engineers at Duke University have developed a wireless, skin-mounted patch that can measure tissue stiffness several centimeters below the surface, offering a new way to monitor muscle health, wound healing, and chronic conditions like skin cancer. The device is smaller than a smartwatch and uses sound waves to assess the mechanical properties of skin and underlying tissue in real time.

Tissue stiffness is a key indicator in many medical scenarios. It can signal inflammation, fluid buildup, or tumor growth, and is often used to track recovery from injuries. Traditionally, clinicians rely on bulky ultrasound machines to measure stiffness, which limits access and portability. Duke’s new patch changes that by offering a compact, wearable alternative that communicates wirelessly via Bluetooth and can be worn anywhere on the body.

The device works by sending sound waves across the skin and listening to the resulting vibrations. Lower-frequency waves penetrate deeper, while higher frequencies stay near the surface. By sweeping from 50 to 800 Hertz, the patch can distinguish between skin and deeper tissue layers. It then uses a two-layer model to analyze stiffness at each depth, similar to how tapping on a wall helps locate a stud behind drywall.

The patch was developed by Xiaoyue Ni, assistant professor of mechanical engineering and materials science, and her PhD student Chenhang Li. Ni was inspired to explore the technology after giving birth and realizing she could use it to monitor her body’s milk supply. She believes the device could be adapted for a wide range of applications, from athletic training to fluid management during emergency care.

The team envisions future versions embedded in sports gear, medical wraps, or everyday clothing, creating a continuous health dashboard for the body’s hidden layers. Athletes could use it to optimize workouts, detect fatigue before injury, and fine-tune recovery schedules. Patients with chronic conditions could track changes in tissue health without needing to visit a clinic.