11. Jun 2026
Caltech develops carbon nanotube-PU material for wearable sensors
Researchers at California Institute of Technology (Caltech) have developed a soft, stretchable bioelectronic material that combines carbon nanotubes with polyurethane, paving the way for more reliable wearable and implantable sensors.
The material, known as stretchable interface for resilient electrochemical sensing (SIRES), was developed by a team led by Wei Gao. It is designed to maintain stable electrical performance even when subjected to large deformations associated with movement of skin, muscles and internal organs.
According to Caltech, SIRES can withstand strains of up to 300% without losing signal quality. The material consists of three layers: a liquid-metal conductor, a stretchable carbon nanotube electrode and a chemically functional coating that enables sensing of biomarkers. The carbon nanotubes are embedded within a polyurethane matrix, giving the structure both conductivity and mechanical resilience.
The researchers said conventional implantable electronics often suffer from cracking, delamination and loss of electrical performance because of the large mismatch between rigid electronic components and soft biological tissues. Polyurethane's elasticity and biocompatibility, combined with the conductivity of carbon nanotubes, allowed the team to create a material capable of conforming closely to moving tissues while maintaining adhesion.
In laboratory tests, SIRES-based devices continued to operate during vigorous physical activity and when attached to highly deformable organs, including the heart and gastrointestinal tract. The sensors were able to monitor biochemical signals without significant degradation in performance.
The work was reported in the journal Science in a paper published on May 28. The researchers believe the technology could enable a new generation of wearable and implantable medical devices for continuous health monitoring and personalised medicine.
Illustration: Wei Gao and a team at Caltech have developed a bioelectronic material called a stretchable interface for resilient electrochemical sensing (SIRES), meeting a key need for the next generation of wearable and implantable sensors. SIRES-based bioelectronics can stretch when applied to tissue and organs.
Credit: Gao Lab/Caltech