A Flexible and Biodegradable Piezoelectric-Based Wearable Sensor for Non-Invasive Monitoring of Dynamic Human Motions and Physiological Signals

Recent progress in flexible sensors and piezoelectric materials has enabled the development of continuous monitoring systems for human physiological signals as wearable and implantable medical devices. However, their non-degradable characteristics also lead to the generation of a significant amount of non-decomposable electronic waste (e-waste) and necessitate a secondary surgery for implant removal. Herein, a flexible and biodegradable piezoelectric material for wearable and implantable devices that addresses the problem of secondary surgery and e-waste while providing a high-performance platform for continuous and seamless monitoring of human physiological signals and tactile stimuli is provided. The novel composition of bioresorbable poly(l-lactide) and glycine leads to flexible piezoelectric devices for non-invasive measurement of artery pulse signals in near-surface arteries and slight movement of the muscle, including the trachea, esophagus, and movements of joints. The complete degradability of piezoelectric film in phosphate-buffered saline at 37 degrees C is also shown. The developed pressure sensor exhibits high sensitivity of 13.2 mV kPa(-1) with a response time of 10 ms and shows good mechanical stability. This piezoelectric material has comparable performance to commonly used non-degradable piezoelectric materials for measuring physiological signals. It can also be used in temporary implantable medical devices for monitoring due to its degradable nature.