Wearable biosensors are transforming healthcare by providing real-time, non-invasive monitoring of biomarkers in sweat, saliva, or interstitial fluid. These devices can reveal hydration levels, muscle activity, and early signs of disease, but many struggle with flexibility or can only track a single marker. The complexity of human physiology calls for systems that are multifunctional, skin-friendly, and capable of maintaining accuracy under real-world movement and strain. Now, a breakthrough in wearable sensor design paves the way for stretchable, skin-friendly systems for non-invasive health monitoring.

Researchers at the Shenzhen Institute of Advanced Technology (Shenzhen, China) and Fudan University (Shanghai, China), along with collaborators, have designed a new biosensor that uses a hybrid microstructure (HMS) electrode system combining wavy flexibility with microcrack stress relief. This innovation enables the sensor to bend and stretch while monitoring multiple signals, including pH, ion concentrations (Ca²?, Na?, K?), and EMG activity.

The hybrid microstructure integrates wave-like undulations and microcrack formations in gold electrodes placed on a flexible substrate. These features distribute stress across the electrode, preventing failure under repeated stretching. The electrodes were further functionalized with PEDOT:PSS for ion detection and polyaniline (PANI) for pH sensing, then encapsulated in ultrathin Styrene-Ethylene-Butylene-Styrene (SEBS) films for stability. Together, this design allows the biosensor to capture multiple biomarkers while remaining resilient to strain.

Tests showed that the electrodes maintained conductivity after 5,000 cycles of stretching up to 60%. In real-world use, a volunteer wearing the device during a 20-minute run demonstrated that it could accurately monitor sweat ion changes and muscle activity in real time. The findings, published in eScience, highlighted the system’s superior stretchability and multiparameter monitoring compared with conventional wearable biosensors.

Biosensors with a hybrid microstructure design offer new opportunities for continuous monitoring of athletes, patients, and workers, helping detect dehydration, electrolyte imbalance, or muscle fatigue before complications occur. Their thin, soft design makes them suitable for integration into clothing or skin patches. Going forward, the research team plans to enhance breathability, scalability, and wireless connectivity to bring the device closer to practical clinical and consumer use.

“This hybrid microstructure design is a game-changer for wearable health tech. We've bridged a longstanding gap between mechanical flexibility and multifunctional sensing,” said Professor Zhiyuan Liu, senior author of the study. By combining stretchability with stable signal capture, our biosensors can conform to the body's movements while providing rich, real-time physiological data. This opens up new possibilities for continuous health tracking in sports, clinical settings, and everyday life.”

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