Wearable and Multifunctional Self-Mixing Microfiber Sensor for Human Health Monitoring

We propose a sensor based on the integration of self-mixing interference (SMI) with microfiber, for human health monitoring. Through the power variation of the reflected light from the microfiber which is embedded into polydimethylsiloxane (PDMS), we are able to accurately monitor pulse waves continuously and in real time, and human blood pressure is successfully monitored via the pulse transmission time (PTT). We measured systolic blood pressure (SBP) and diastolic blood pressure (DBP) in volunteers with a measurement error of$- 0.222\,\,\pm \,\,2.636$mmHg and$- 1.056\,\,\pm \,\,2.198$mmHg, respectively. Long-term health monitoring was also performed for several days, and measurements met the requirements of the American Association for the Advancement of Medical Instrumentation (AAMI). The experimental results show that the sensor is capable of accurately monitoring multiparameter information of human pulse and blood pressure, and has the characteristics of high sensitivity, noninvasive, and long-term monitoring. This application of microfiber to the self-mixing sensor provides an effective solution for smart health monitoring, and has potential applications in disease prevention and healthcare.