CEA-Leti has collaborated with STMicroelectronics to unveil a major step toward practical, continuous biochemical monitoring: a wearable patch prototype that analyses sweat in real time. Powered by ST’s new, high-precision analogue front-end R&D prototype project for solid-state electrochemical sensors and CEA-Leti’s advanced sensing platform, the prototype collects sweat directly from the skin through an adhesive collection layer with an integrated microfluidic circuit.
Electrochemical pilot sensors inside the device track indicators linked to hydration, fatigue, thermal stress, and exertion. After analysis, sweat is evacuated through a microporous evaporation layer. All functional layers are fabricated on flexible substrates thin enough to conform comfortably to the arm.
The small device – called Sweat Patch – combines solid-state prototype sensors, an innovative microfluidic network, and compact wireless electronics. Designed for extreme environmental conditions, it continuously measures three key physiological markers in its first version: pH, sodium, and potassium.
“In this novel system, all the sweat produced is efficiently collected and transported through microfluidic pathways to measurement chambers, each equipped with an electrochemical sensor, and then into the drainage system for disposal,” said Nadège Nief, Deputy Head Micro-Technologies for Biology and Healthcare Division at CEA-Leti. “While earlier generations of analysis rely on only intermittent readings, Sweat Patch ensures a continuous, stable biochemical signal that allows a dramatic improvement in analysis.”
The prototype measures 3cm in diameter and under 1cm thick and was developed under CEA-Leti’s ‘human-use-compliant by design’ framework for health technologies. All materials are medical-grade, non-toxic, and biocompatible.
Monitoring biochemical markers continuously
The Sweat Patch is pioneering a new era of non-invasive, continuous biochemical monitoring by unlocking the rich diagnostic potential found in sweat – often described as a ‘goldmine’ of vital health information. This innovative technology continuously tracks key biochemical markers such as glucose, potassium, sodium, and lactate, providing real-time insights into hydration status, electrolyte balance, physical exertion, and stress levels. At the heart of this breakthrough is ST’s analogue front-end prototype, a compact high-precision potentiostat designed to control and read solid-state electrochemical sensors with exceptional accuracy. When implemented in synergy with ST advanced MEMS motion sensors, the potentiostat could enable seamless fusion of biochemical data with detailed motion and activity metrics. This powerful combination transforms raw measurements into deeply contextualised, actionable insights – offering a comprehensive understanding of an individual’s physiological state in real time.
Enrico Alessi, R&D Manager of System Architectures in the Central R&D of Analog, Power & Discretes, MEMS and Sensors Group at STMicroelectronics, highlighting the innovation, states: “The Sweat Patch goes beyond traditional monitoring solutions, delivering meaningful, personalised data that can drive smarter decisions across diverse environments. Potential applications of this innovative technology are vast and impactful, spanning from personal fitness optimisation, occupational health and safety to early-warning health monitoring, and non-invasive clinical screening. In industrial settings, continuous sweat analysis can serve as an early detector of heat stress and electrolyte imbalances, helping to safeguard worker health.”
Andreja Erbes, Director of Technology Scouting and R&D Partnerships at STMicroelectronics, adds: “Interesting applications are emerging from companies investing in biochemical markers for wearable devices that offer non-invasive, continuous, and context-aware solutions. Additionally, new markets such as food analysis, industrial process control, and environmental monitoring are showing great potential, leveraging the capabilities of ST’s R&D prototype and highlighting its versatility beyond healthcare.”
Yohann Thomas, research engineer and electrochemical-sensors expert at CEA-Leti, explains: “Sweat Patch demonstrates what becomes possible when electronics, microfluidics, and solid-state chemistry are developed as a unified system rather than separate components. Real-time biochemical sensing depends on every part of the chain performing reliably on the skin.”
Looking ahead, CEA-Leti and STMicroelectronics are focused on advancing the technological maturity of this integrated platform, industrialising electrochemical sensors with additional biochemical biomarkers, while also enhancing device connectivity and data security to enable seamless data transmission. This complete platform serves as a technology enabler for future customers developing next-generation contextual sensing solutions.
