Flexible Sensing-Memory Platform for Physiological Health Monitoring

Researchers at Taiyuan University of Technology and The University of Tokyo have developed a fully flexible sensing-memory integrated system that solves the traditional mechanical mismatch between rigid silicon-based memory and flexible sensors, according to Tsinghua University Press. The monolithically integrated platform combines an organic thin-film transistor pressure sensor with a flexible floating-gate organic thin-film transistor memory, offering continuous physiological signal acquisition, storage, and wireless transmission for next-generation wearable health monitoring devices.

Flexible Pressure Sensor Performance and Mechanics

The newly developed pressure sensor operates across a wide range of 0 to 40 kPa and delivers a fast response time of 34 milliseconds. Investigators found that the device maintains stable mechanical performance after enduring 5,000 bending cycles. It also operates reliably across temperatures ranging from −20 °C to 60 °C. When attached directly to human skin over finger joints, wrists, and the throat, the sensor generates distinct current variation signals. These signals accurately track joint bending angles and capture intermittent coughing episodes in real time.

Floating-Gate Memory Integration and Wireless Data Transmission

The integrated floating-gate memory achieves a large memory window of 18 V under ±80 V program and erase biases, alongside a data retention time exceeding 10⁵ seconds, according to the research team. The memory component remains stable following 3,000 bending cycles. To test data handling capabilities, the team used a 1×9 memory array to store 7-bit ASCII-encoded characters alongside two check bits. This stored physiological information is then transmitted wirelessly to a mobile application using Bluetooth Low Energy technology.

Overcoming Traditional Wearable Device Bottlenecks

Comparative analysis shows that this integrated system offers a shorter response time and longer data retention capability than previously reported organic thin-film transistor-based pressure sensors and organic memories used for physiological monitoring. Investigators emphasized that this deep integration addresses the key bottleneck of data acquisition and processing separation in traditional wearable devices. The platform offers a low-cost solution spin-coating fabrication process that paves the way for electronic skin capable of simultaneous sensing, data storage, and wireless telemetry.