Ultrasensitive Fingertip-Contacted Pressure Sensors To Enable Continuous Measurement of Epidermal Pulse Waves on Ubiquitous Object Surfaces

The fingertip-pulse waveform carries abundant information regarding human physiological condition that is fundamental for directly extracting physiological parameters. Making the surfaces of ordinary objects that are often in contact with fingertips, such as tables and computers, capable of perceiving dynamic epidermal pulse signals has great significance for accurately assessing health conditions without restrictions on time and place. Here, we demonstrate the materials and design of a nanohemispherical pressure sensor that can be attached to ubiquitous objects' surfaces to monitor fingertip pulse. The portable sensor achieved an ultrasensitivity of 49.8 mV/Pa, a prominent response time of less than 6 ms, and long-term durability of more than 4 months. As demonstrated, the sensor is utilized to measure subtle fingertip-pulse waves and extract characteristic points of the waveform on the surface of keyboards, mobile phones, and human skin. Given the superior performance of the sensor, a real-time, wireless arteriosclerosis monitoring system is developed. By analyzing the characteristic parameters of the pulse waveforms measured from 54 volunteer participants, the antidiastole of arteriosclerosis could be instructively diagnosed. The sensor proposed in this work is expected to be a competitive alternative to current complicated medical equipment and to be extensively applied in wireless cardiovascular monitoring systems.