Flexible sensing-memory integrated platform advances physiological health monitoring

A wearable health monitoring system that achieves seamless integration of sensing and memory functions is of great significance for real-time physiological signal acquisition and processing. However, traditional solutions relying on hybrid integration of rigid silicon-based memory with flexible sensors suffer from mechanical mismatch and interface complexity, which limit their practical application in continuous physiological monitoring. A research team has recently developed a fully flexible sensing-memory integrated system. This system, fabricated using a low-cost solution spin-coating process, integrates a flexible floating-gate organic thin-film transistor memory with an organic thin-film transistor pressure sensor.

This research was conducted by researchers at Taiyuan University of Technology and The University of Tokyo, who proposed a monolithically integrated sensing-memory system. The pressure sensor features a wide operating range of 0–40 kPa, a fast response time of 34 ms, and maintains stable performance after 5,000 bending cycles and across temperatures ranging from −20 °C to 60 °C. When attached to finger joints, wrists, and the human throat, the device generates current variation signals that accurately track joint bending angles and intermittent coughing.

The integrated floating-gate memory exhibits a large memory window of 18 V under ±80 V program/erase biases, a retention time exceeding 10⁵ seconds, and remains stable after 3,000 bending cycles. The research team utilized a 1×9 memory array to store 7-bit ASCII-encoded characters along with two check bits, with the stored information wirelessly transmitted to a mobile application via Bluetooth Low Energy technology.

Comparative analysis shows that this integrated system offers a shorter response time and longer data retention capability compared to previously reported OTFT-based pressure sensors and organic memories used for physiological monitoring.

The researchers emphasized that this deep integration of sensing and memory addresses the key bottleneck of the separation between data acquisition and processing in traditional wearable devices. It provides an innovative technological platform for realizing low-cost, fully flexible electronic skin capable of simultaneous physiological sensing, data storage, and wireless transmission.

This work was supported by Fundamental Research Program of Shanxi Province (202403021221067, 202403021221203), Patent Transformation Program of Shanxi Province (202405020, 202401004) and China Scholarship Council funding 202206935020.