Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

Abstract

Real-time and continuous monitoring of physiological signals is essential for mobile health, which is becoming a popular tool for efficient and convenient medical services. Here, an active pulse sensing system that can detect the weak vibration patterns of the human radial artery is constructed with a sandwich-structure piezoelectret that has high equivalent piezoelectricity. The high precision and stability of the system result in possible medical assessment applications, including the capability to identify common heart problems (such as arrhythmia); the feasibility to conduct pulse palpation measurements similar to well-trained doctors in Traditional Chinese Medicine; and the possibility to measure and read blood pressure.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201803413.imitate the TCM practice for health assessments without well-trained, real doctors. Previously, human pulse waves have been measured using sensors based on different detection mechanisms, such as optics, [16,17] image processing, [15,18,19] acoustics, [20] and pressure means, [21][22][23][24][25][26][27][28][29] etc. Among these, active pressure sensors based on the working principles of piezoelectricity [21][22][23][24] or triboelectricity [7,8] are the more intuitive and sensitive method to detect pulse waves, as these sensors can accurately and directly reflect the weak vibration of the radial artery to better imitate the pulse diagnosis in TCM. Several vertical contact-separation and single-electrode triboelectric pressure sensors have been published to detect human motion and physiological signals, with advantages of thin, flexible, and excellent sensitivity. [30] However, vertical contact-separation devices are composed of two separated parts, which increases the difficulty of assembly and operation in practice. Single-electrode triboelectric sensors have been proposed to address this issue but the exposed residual charges on the sensor surface can be easily leaked. Piezoelectret is flexible, lightweight, and have large and stable equivalent piezoelectric coefficient for high sensitivity. [25] Furthermore, sensors based on piezoelectret materials can alleviate the aforementioned issues in triboelectric sensors to detect physiological signals.In this work, we use an active and flexible pulse wave sensing system based on a fluorinated ethylene propylene (FEP)/Ecoflex/FEP sandwich-structured piezoelectret for piezoelectriclike detections. [25,26,31] Several key features are accomplished from the prototype sensing systems: 1) excellent precision and stability capable of differentiating and classifying pulses from different volunteers coupled with the help of big data analyses; 2) the identification of a common heart problem (arrhythmia) from volunteers who were previously diagnosed in hospitals equipped with advanced and bulky electrocardiogram (ECG) setups; 3) the feasibility in recording and revealing the blood pressure using the pulse sensing system instead of a ...

Review of Printed Electrodes for Flexible Devices

“…Increasing demand for high performance devices, drives the development of alternative, or novel structures of devices and the use of new materials Wang et al, 2018). In recent years, flexible and stretchable electronics have developed at an unprecedented rate and are involved in various applications, including sensors (Chu et al, 2018;Pan et al, 2018), displays , solar cells Xi et al, 2017;Zhang et al, 2017), supercapacitors Wang M. et al, 2017), electronic skins (E-skins) (Lou et al, 2017;Bermúdez et al, 2018;Byun et al, 2018) and wearable electronics (Lee et al, 2017). Some applications are shown in Figure 1.…”

Highly Efficient Mechanoelectrical Energy Conversion Based on the Near‐Tip Stress Field of an Antifracture Slit Observed in Scorpions

“…In the process of mechanosensing, the dispersed tiny mechanical energy is converged on nanoscale near‐tip stress field at the antifracture slit tip and then converted into electric energy by mechanosensory neuron. There is an urgent need for improving the mechanoelectrical energy conversion efficiency of ind‐MTMs which have been widely used for driving low‐power portable and wearable electronic device without any external power supplies, harvesting clean mechanical energy from the ambient environment and improving the sensitivity of mechanical sensors . The proposed theory in this work indicates that the ultrasensitive mechanoreceptor of scorpion represents a completely new paradigm in maximizing the mechanoelectrial energy conversion efficiency of ind‐MTMs because the physical essence of mechanosensing is highly efficient conversion of mechanical energy contained in the mechanical signals into electrical energy which nervous system can be used.…”

“…There is an urgent need for developing new methods to achieve highly efficient conversion of other types of energy to electrical energy . The piezoelectric‐based industrial mechanoelectrical transducing micro/nanosystems (ind‐MTMs), harvesting tiny mechanical energy from working environment and then converting into electrical energy, have been closely studied for advanced technological applications in mechanical energy harvesting, ultrasensitive mechanical sensors, self‐powered portable and wearable electronics, electronic skins, etc. One of the grand challenges in the current study of ind‐MTMs is to maximize energy conversion efficiency while decreasing its size.…”

Wearable Electronics Based on 2D Materials for Human Physiological Information Detection

“…The heartbeat reflects the heart function of pumping oxygen into human blood over the whole body and removing carbon dioxide out of the lung. The heartbeat is the frequency of cardiac cycles, and the wave detail varies for different ages, body states, and even mental states . Recently, our group has reported rGO‐based pressure sensor with high sensitivity and wearable properties for subtle signals detection .…”