A research team announced on Jul. 30 the development of a fully flexible sensing-memory integrated system designed for wearable health monitoring. The system, created by researchers at Taiyuan University of Technology and The University of Tokyo, integrates sensing and memory functions to enable real-time physiological signal acquisition and processing.
Traditional solutions often rely on hybrid integration of rigid silicon-based memory with flexible sensors, which can result in mechanical mismatch and interface complexity. These issues have limited their use in continuous physiological monitoring applications. The new system uses a low-cost solution spin-coating process to fabricate a flexible floating-gate organic thin-film transistor memory alongside an organic thin-film transistor pressure sensor.
The pressure sensor component operates within a range of 0–40 kPa, offers a response time of 34 milliseconds, and maintains stable performance after 5,000 bending cycles as well as across temperatures from −20 °C to 60 °C. When attached to finger joints, wrists, or the human throat, the device produces current variation signals that track joint bending angles and intermittent coughing events.
The integrated floating-gate memory features an 18-volt memory window under ±80 volt program/erase biases and demonstrates data retention exceeding 100,000 seconds while remaining stable after 3,000 bending cycles. A one-by-nine memory array is used to store seven-bit ASCII-encoded characters with two check bits; this information is wirelessly transmitted via Bluetooth Low Energy technology to mobile applications.
According to comparative analysis conducted by the research team, this integrated system provides shorter response times and longer data retention compared with previously reported organic thin-film transistor-based pressure sensors and memories for physiological monitoring purposes. The researchers said that “this deep integration of sensing and memory addresses the key bottleneck of the separation between data acquisition and processing in traditional wearable devices,” and added that it offers "an innovative technological platform for realizing low-cost, fully flexible electronic skin capable of simultaneous physiological sensing, data storage, and wireless transmission."
