Flexible bioelectronic devices are designed to work on soft, moving biological tissues. But when the body stretches, bends, contracts, or remodels, maintaining accurate molecular sensing becomes a major challenge. A research team from Peking University and the California Institute of Technology has developed a strain-resilient, intrinsically stretchable electrochemical biointerface that can maintain reliable molecular sensing under large mechanical deformation. The study, titled "Strain-resilient intrinsically stretchable electrochemical biointerfaces," was recently published in Science.
Background
Rapid progress has been made in flexible bioelectronics for monitoring physical signals such as heart activity, muscle activity, temperature, and pulse. However, continuous detection of molecular biomarkers remains difficult. Biomarkers such as glucose, lactate, pH, ions, and inflammatory markers can provide direct information about metabolism, disease progression, and treatment response. Still, electrochemical sensors must remain stable while tissues stretch, contract, and remodel. In real physiological environments, tissue motion can alter electrode morphology, disrupt conductive networks, and damage sensing layers, leading to signal drift or reduced reliability.
Why it matters
For practical wearable and implantable bioelectronics, mechanical stretchability alone is not enough. Devices must also maintain high-fidelity signal transmission and sensing while attached to dynamic tissues. To address this need, the researchers developed a strain-resilient, intrinsically stretchable interface for resilient electrochemical sensing (SIRES). Unlike conventional designs that place relatively rigid electrodes on flexible substrates, SIRES integrates electrical conduction, interfacial regulation, and sensing function into a unified stretchable architecture.
Key findings
SIRES combines three functional layers: a strain-resilient conductor, an electrically tunable interface, and a stretchable functional coating. Together, these layers maintain stable electrochemical output even when stretched up to 300%.
The platform works with multiple sensing modes to monitor uric acid, glucose, and pH in sweat, and, when integrated into breathable headbands and wristbands, has demonstrated steady performance during exercises such as biking, running, rowing, and elliptical machine training.
Importantly, SIRES has also demonstrated promising capabilities for monitoring disease-related biomarkers. In implantable applications, it enables monitoring of gastric dietary responses, gastric leaks, analysis of inflammation of diabetic wounds, and measurement of lactate levels associated with inflammatory bowel disease and hydrogen peroxide levels associated with bladder tumors. The device showed good biocompatibility in animal tests, indicating prospects for long-term use inside the body.
Future Implications
SIRES moves flexible bioelectronics beyond simple stretchability to strain-resilient molecular sensing. It provides a versatile platform for wearable health tracking, chronic disease management (including diabetes and cancer), postoperative complication warning, wound infection assessment, gastrointestinal monitoring, and closed-loop precision medicine.
*This article is featured in PKU News "Why It Matters" series. More from this series.
Read more: https://www.science.org/doi/10.1126/science.aed1630
Written by: Akaash Babar
Edited by: Chen Shizhuo
Source: PKU Shenzhen Graduate School (Chinese)