Inspired by DNA’s double helix, Shinshu University researchers have created a robust and flexible fiber sensor that can endure extensive movement, paving the way for more durable and advanced wearable technologies.
In a groundbreaking development, researchers at Shinshu University have introduced a novel flexible fiber sensor inspired by the DNA double helix structure, poised to revolutionize the wearable technology landscape.
This innovative design, described in an article published in the journal Advanced Science, not only increases the durability and flexibility of the sensors but also simplifies their integration into wearable devices, particularly those used on body joints.
A Leap in Sensor Design
Conventional fiber sensors, typically incorporating electrodes at both ends, often succumb to wear and tear under repetitive movement, especially when applied to joints like fingers and knees.
The dual-helical approach, developed by the Shinshu University team, mitigates this issue by placing both electrodes on one end. This strategic design choice results in a more resilient sensor capable of withstanding the mechanical stresses associated with daily movements.
“Effective electrode design is critical to the performance and lifespan of wearable sensors. But in one-dimensional fiber sensors, this has long been a challenge. Our design addresses this issue directly,” lead author Chunhong Zhu, an associate professor in the Institute for Fiber Engineering and Science at Shinshu University, said in a news release.
Engineering Innovation
Taking cues from DNA’s stability maintained by hydrogen bonds, the researchers developed a sensor by twisting two coaxial fibers together, forming a stable double-helix structure.
Each fiber comprises a conductive inner core made of multi-walled carbon nanotubes (MWCNTs) and an insulating outer layer containing thermoplastic polyurethane (TPU) and titanium dioxide (TiO2) nanoparticles, enhancing the fiber’s strength and flexibility.
After heat treatment, the fibers naturally formed a double helix with built-in positive and negative terminals on one end, significantly simplifying the wiring process — a common challenge in existing fiber sensor designs.
“The TT/MT dual-helical fiber has two electrodes at one end and a free end with no electrodes, greatly simplifying the wiring of flexible sensors,” added co-author Ziwei Chen.
The resulting dual-helical fiber sensor boasts impressive durability and flexibility, enduring over 1,000 stretching cycles and extending more than 300% beyond its original length without breaking.
Its compact size, measuring less than 1 mm in diameter, facilitates seamless integration into wearable textiles.
Practical Applications
This advancement opens up a plethora of applications, particularly for tracking complex body movements. With the electrode side securely attached to less mobile areas like the back of the hand or cheeks, the sensors can monitor finger gestures, facial expressions and even detect breathing patterns during sleep.
For instance, in one test, the researchers integrated the sensor into a glove and employed a machine-learning model to identify six common hand gestures with 98.8% accuracy.
Another test demonstrated the sensor’s capability to transmit Morse code wirelessly, using finger movements, highlighting its potential in assistive technologies for people with disabilities.
Moreover, the new design shows promise in applications requiring real-time remote monitoring, such as rehabilitation and sports training. Bluetooth-connected wearables embedded with these sensors could provide immediate alerts during high-risk activities like mountaineering, potentially signaling emergencies such as falls or health crises like hypoxia.
Future Prospects
With this cutting-edge design, the researchers aspire to spearhead the next generation of intelligent fibers that are not only resilient and sensitive but also user-friendly for everyday wear.
“Our design strategy, exemplified by the TT/MT dual-helical fiber highlighted in our study, also provides a versatile approach that can inspire the development of various intelligent fibers tailored for different applications,” added Zhu.
Source: Shinshu University