3D-Printed microfibers add ECG sensing to everyday objects

Pencils that monitor heart rate, pliers that detect muscle fatigue, or robotic hands that sense touch – all made possible by a new 3D-printing technique for ultra-thin conductive microfibers. Developed by researchers at the University of Cambridge, in collaboration with the Hong Kong University of Science and Technology (GZ) and Queen Mary University of London, the method could redefine how we interact with objects and machines in daily life.

The team has created a one-step adaptive fibre-deposition process using 3D printing. This approach allows conductive polymer fibres thinner than a human hair to be printed directly onto glass, plastic or leather – exactly where sensing or connectivity is needed.

The transparent fibers, made from the polymer PEDOT:PSS, can detect real-time electrocardiogram (ECG) and surface electromyography (sEMG) signals.

In one demonstration, an array of 400 conductive microfibers was printed around a robotic finger. When a human finger touched it, the system successfully measured ECG signals, proving its ability to turn ordinary objects into precise biosensors.

The same principle was applied to everyday tools such as a pencil and a plier handle, where printed fibers captured sEMG signals from the user’s thumb tendon during writing or gripping tasks.
By integrating these functions, the technology merges familiar objects with real-time physiological monitoring without bulky wearables or embedded electronics.

“Transient electronic skins such as the one demonstrated here are crucial to enable robots and prosthetics to become more human-interactive and mimic the sense of touch,” said Stanley Ka, PhD student in the Biointerface Research Group at Cambridge’s Department of Engineering.

The researchers see multiple opportunities for applying this method in healthcare, telemedicine and industrial safety:

• Home-based care and elderly monitoring: robots or smart tools that check ECG without physical sensors
• Emergency response: robotic systems assessing cardiac activity before help arrives
• Workplace safety: detecting fatigue or stress in workers handling tools
• Collaborative robotics: adjusting robot behavior based on human muscle or stress signals

In each scenario, the printed fibers provide continuous, contact-free data while keeping objects lightweight, functional and easy to use.

The microfiber electrodes are long-lasting yet easily removable. After use, they can be wiped off without damaging or staining the original surface – a key advantage for sustainability and reusability.
This approach offers a low-waste pathway to integrate sensing and energy functions into existing products.

“Our approach for integrating customisable electronic functions onto various existing objects as shown, can help in setting up a sustainable Fibre-of-Things (FoT) future – potentially revolutionising medical diagnostics, treatment, and even creating new forms of wearable technology,” said Professor Shery Huang, who leads the Biointerface Research Group.