A July 2, 2025 news item on Nanowerk announces research that employs boron nitride nanotubes in a device for monitoring joint health, Note: Links have been removed,

A research team from the University of Oxford and University College London has developed a wearable device that can track joint torque with precision, potentially transforming the way clinicians and patients monitor joint health.

Reported in Nano-Micro Letters (“AI-Enabled Piezoelectric Wearable for Joint Torque Monitoring”), the new technology integrates advanced materials and artificial intelligence to provide real-time data from everyday movements.

The device relies on boron nitride nanotubes (BNNTs) embedded in a soft polymer called polydimethylsiloxane (PDMS). These nanotubes possess exceptional mechanical strength and piezoelectric properties, meaning they generate electrical signals in response to movement or pressure. When worn on the knee, the composite material responds to joint motion by producing signals that can be interpreted to measure torque—the rotational force exerted on the joint.

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A July 7, 2025 Shanghai Jiao Tong University Journal Center press release on EurekAlert provides information about the research in bullet point form,

In the pursuit of more effective and accessible solutions for joint health monitoring, researchers are constantly seeking innovative ways to enhance the capabilities of wearable devices. A recent article published in Nano-Micro Letters, authored by Professor Jin-Chong Tan and Professor Hubin Zhao from the University of Oxford and University College London, presents a groundbreaking AI-enabled piezoelectric wearable device for accurate joint torque sensing, leveraging the unique properties of boron nitride nanotubes (BNNTs).

Why This Research Matters

• Enhanced Joint Health Monitoring: Traditional methods for assessing joint torque are often confined to laboratory settings or require complex setups, limiting their feasibility for real-world applications. This new wearable device offers a portable, non-invasive solution for continuous joint torque monitoring, crucial for evaluating joint health, guiding interventions, and monitoring rehabilitation progress.
• High Sensitivity and Accuracy: The device’s high-sensitivity BNNTs/polydimethylsiloxane composite enables precise and dynamic knee motion signal detection, while the lightweight neural network processes complex signals for accurate torque, angle, and load estimation, providing reliable data for joint health assessment.
• Low-Cost and Accessible Solution: The compatibility of the materials and design with low-power, resource-limited settings makes this wearable device a cost-effective and accessible solution for diverse populations across regions with varying levels of development, potentially revolutionizing joint health monitoring on a global scale.

Innovative Design and Mechanisms

• Boron Nitride Nanotubes and Polydimethylsiloxane: BNNTs are highlighted as ideal materials for constructing high-performance piezoelectric sensors due to their exceptional mechanical strength, thermal stability, and intrinsic piezoelectric properties. The uniform dispersion of BNNTs in a PDMS matrix results in a highly sensitive piezoelectric film capable of capturing complex knee motion signals.
• Inverse Design Structure: The wearable device employs an inverse-designed structure with a negative Poisson’s ratio, precisely matched to the biomechanics of the knee joint. This unique design ensures optimal biomechanical compatibility, enhancing motion tracking fidelity and enabling detailed sensing of complex loading conditions during knee movements.
• Artificial Intelligence Integration: The integration of a lightweight on-device artificial neural network allows for real-time processing and analysis of the complex piezoelectric signals generated during movement. The AI algorithm accurately extracts targeted signals and maps them to corresponding physical characteristics, such as torque, angle, and loading, providing valuable insights into joint health.

Applications and Future Outlook

• Joint Health Monitoring: This wearable device can continuously monitor joint torque, offering valuable data for the evaluation of joint health and early detection of potential issues. It can be particularly beneficial for individuals with musculoskeletal conditions, the elderly, and athletes, enabling timely interventions and personalized rehabilitation plans.
• Rehabilitation and Injury Prevention: By providing real-time torque assessment and risk assessment of joint injury, the device can play a crucial role in rehabilitation programs, ensuring safe and effective recovery. It can also help in preventing injuries by alerting users to potentially harmful joint movements or excessive torque.
• Future Research Directions: Future research should focus on further optimizing the sensing materials, device design, and AI algorithms to enhance the performance, accuracy, and adaptability of the wearable device. Exploring additional complementary modalities and integrating the device with wearable robotics or exoskeletons could further expand its applications and utility in various fields.

This innovative AI-enabled piezoelectric wearable device represents a significant step forward in joint health monitoring, offering a low-cost, high-sensitivity solution with broad potential applications. Stay tuned for more groundbreaking research from Professor Jin-Chong Tan and Professor Hubin Zhao’s team as they continue to push the boundaries of wearable technology and contribute to improved joint health and rehabilitation outcomes.

Here’s a link to and a citation for the paper,

AI-Enabled Piezoelectric Wearable for Joint Torque Monitoring by Jinke Chang, Jinchen Li, Jiahao Ye, Bowen Zhang, Jianan Chen, Yunjia Xia, Jingyu Lei, Tom Carlson, Rui Loureiro, Alexander M. Korsunsky, Jin-Chong Tan & Hubin Zhao. Nano-Micro Lett. 17, 247 (2025) DOI: https://doi.org/10.1007/s40820-025-01753-w Published: 03 May 2025

This paper is open access.