Researchers at Seoul National University have developed 3D-printed carbon nanotube (CNT) sensors for smart health monitoring.

The researchers have perfected a photopolymerisation 3D method that simultaneously provides high stretchability and electrical conductivity — something that has proved elusive previously.

The result is a range of highly stretchable, electrically conductive CNT-nanocomposites.
The researchers have manufactured piezoresistive sensors from the new material and have integrated them into a wearable health monitoring device.

The new fabricated material can stretch up to 223% of its original length before breaking, while still achieving an electrical conductivity of 1.64 ×10−3 S/m, surpassing that of previously reported materials. It has also achieved a printing resolution of 0.6 mm.

To demonstrate practical applicability, the researchers used the optimised CNT nanocomposite to 3D print flexible triply periodic minimal surface (TPMS)-based piezoresistive sensors that showed high sensitivity and reliable performance. They integrated these sensors into an insole to create a smart-insole platform. Using this platform, the team could monitor the pressure distribution at the bottom of the foot in real time, detecting different human movements and postures.

The research team has been led by Professor Keun Park and Associate Professor Soonjae Pyo from the Department of Mechanical System Design Engineering at Seoul National University of Science and Technology in Korea.

“Our new CNT-nanocomposites are optimised specifically for VPP-based processes, allowing fabrication of highly complex 3D structures,” said Professor Park. “We also used these materials to additively manufacture new piezoresistive sensors and integrated them into a wearable health monitoring device.”

“The developed smart-insole device demonstrates the potential of our CNT nanocomposites for 3D printing the next generation of highly stretchable and conductive materials,” said Professor Pyo, “We believe these materials will be indispensable for wearable health monitors, flexible electronics and smart textiles.”

Their study, Photopolymerisation additive manufacturing of highly stretchable CNT nanocomposites for 3D-architectured sensor applications, is available online and will be published in Volume 372 of the journal Composite Structures on November 15, 2025.