Electronic Health Monitoring Research Articles

An Empirical Study on Transmission Beamforming for Ultrasonic Guided-Wave Based Structural Health Monitoring.

The development of reliable structural health monitoring techniques is enabling a healthy transition from preventive to condition-based maintenance, hence leading to safer and more efficient operation of different industries. Ultrasonic guided-wave based beamforming is one of the most promising techniques, which supports the monitoring of large thin-walled structures. However, beamforming has been typically applied to the post-processing stage (also known as virtual or receiver beamforming) because transmission or physical beamforming requires complex hardware configurations. This paper introduces an electronic structural health monitoring system that carries out transmission beamforming experiments by simultaneously emitting and receiving ultrasonic guided-waves using several transducers. An empirical characterization of the transmission beamforming technique for monitoring an aluminum plate is provided in this work. The high signal-to-noise ratio and accurate angular precision of the physical signal obtained in the experiments suggest that transmission beamforming can increase the reliability and robustnessof this monitoring technique for large structures and in real-world noisy environments.

Washable and flexible screen printed graphene electrode on textiles for wearable healthcare monitoring

Electrocardiogram (ECG) is an essential route to monitor and prevent cardiovascular related disease. Conventional silver/silver chloride (Ag/AgCl) electrodes are not able to be used for long-term monitoring due to the drying of gel and skin irritation. Graphene has been investigated as a promising material for wearable health-monitoring electronics. Here, a graphene-coated textile electrode was developed for ECG monitoring. The graphene electrode was prepared by screen printing graphene ink on a pre-modified textile substrate. The electrical resistance of the graphene textile electrode can be controlled by increasing the printing passes. The ECG signals obtained by the graphene textile electrode showed comparable performance to the conventional Ag/AgCl electrode. The graphene textile electrode shows satisfactory washability, high flexibility and good tortuosity. The performance of the ECG signal shows negligible change over nine washing cycles and 2000 bending cycles. Overall, the screen-printed graphene textile electrode in this work presents an inexpensive fabrication platform solution for long-term healthcare monitoring in wearable electronics.

Supertough and ultrasensitive flexible electronic skin based on nanocellulose/sulfonated carbon nanotube hydrogel films

Flexible TOCN/SCNT hydrogel film E-skin prepared by a simple method exhibited excellent sensing performance and high strength, indicating potential application for wearable electronic devices, health monitoring, and artificial intelligence.

Blood pressure monitoring system: real time-continuous and noninvasive-electronic, based on magnetic dipole moment of the proton spin of hydrogen atoms in the blood

This research is motivated by the fact that blood pressure monitoring devices currently available cannot be integrated practically with other electronic health monitoring devices. The research is aimed to obtain a real time-continuous and noninvasive-electronic blood pressure monitoring system with a magnetic coil technique. This technique is a simplified form of the nuclear magnetic resonance (NMR) technique because the induced EMF that is obtained does not involve resonance but rather by sudden population changes and relaxation of the magnetic dipole moments of the proton spin of hydrogen atoms in the blood, both when systole and diastole. The benefit of this research output is that it can obtain noninvasive-electronic blood pressure monitoring devices, and the monitoring process does not interfere with blood flow in the branchial artery samples, so that the monitoring equipment can be integrated with other health monitoring equipment practically. The methodology of this research was carried out by placing a sample arm between two poles of a permanent magnet with a magnitude (7,300±200) gauss and his or her hand inside the receiver coil (involving 2,000 turns), after going through a 500 times voltage gain an induction EMF (in volts) was displayed on digital storage oscilloscope screen. This is done when the sample is relaxed (17 volts is obtained), shortly after jogging (26 volts), and the relaxed state a few moments later (12 volts). The result is that the induced EMF signal enlarges and widens shortly after jogging but slides back when the sample return to relaxed. It was concluded that this blood pressure monitoring equipment of the magnetic-coil technique could be used as a blood pressure monitor.

Energy-Efficiency Maximization of Self-Sustained Wireless Body Area Sensor Networks

Electronic health monitoring is one of the major applications of wireless body area networks (WBANs) that helps with early detection of any abnormal physiological symptoms. In this letter, we propose and solve an optimization problem that maximizes the energy efficiency (EE) of WBAN consisting of sensor nodes (SNs) equipped with energy harvesting capabilities communicating with an aggregator. We exploit the structure of the optimization problem to provide a suboptimal solution at a lower computational complexity, and derive the mathematical expressions of upper and lower bounds of the source rates of the SN. The simulation results reveal that the optimal allocation of the source rate to energy critical SNs improves the system performance of WBAN in terms of EE during different everyday activities.

Flexible Multimodal Sensors for Electronic Skin: Principle, Materials, Device, Array Architecture, and Data Acquisition Method

Electronic skin (e-skin) is designed to mimic the comprehensive nature of human skin. Various advances in e-skin continue to drive the development of the multimodal tactile sensor technology on flexible and stretchable platforms. e-skin incorporates pressure, temperature, texture, photographic imaging, and other sensors as well as data acquisition and signal processing units formed on a soft substrate for humanoid robots, wearable devices, and health monitoring electronics that are the most critical applications of soft electronics. This artificial skin has developed very rapidly toward becoming real technology. However, the complex nature of e-skin technology presents significant challenges in terms of materials, devices, sophisticated integration methods, and interference-free data acquisition. These challenges range from functional materials, device architecture, pixel design, array structure, and data acquisition method to multimodal sensing performance with negligible interference. In this article, we present recent research trends and approaches in the field of flexible and stretchable multimodal sensors for e-skin focusing on the following aspects: 1) flexible and stretchable platforms; 2) operating principles and materials suitable for pressure, temperature, strain, photograph, and hairy sensor devices; 3) device and integration architectures, including multimodal single cells, three-axis tactile sensors, vertical-stacked sensor arrays, active matrix sensor arrays, and integration electronics; 4) reliable acquisition methods for various texture sensing and machine-learning algorithms for processing tactile sensing data; and 5) future outlook.

Hierarchical Nico Layered Double Hydroxidesnanosheets on Carbonized CNT/Cotton As a Highperformance Flexible Supercapacitor

Flexible electrodes, unlike the traditional ones, are highly integrated and portable, have attracted great attention in modern electronics fields. They can be served as essential parts in flexible supercapacitors and are critical items in the energy storage system for intelligent electronic products and health monitoring system. The core criteria to design a qualified flexible supercapacitor are high flexibility, stability and capacitance. Cotton fabric is a good choice owing to the properties like low price, easily available and hydrophilicity, in which the hydroxyl groups make it favorable for adsorbing water and reacting with active materials. Carbon nanotubes (CNT) are widely used electrode materials with the merits of high specific surface area, good chemical stability, low resistance, thermal stability, high flexibility and excellent electrical properties. However, it is hard to obtain ideal properties only combining carbon nanotubes with cotton, because the low capacity of carbon nanomaterials. Layered double hydroxides (LDHs) are promising Faradaic materials for the construction of high-performance supercapacitors, due to their unique two-dimensional lamellar structures and remarkable stability. Herein, hierarchical porous NiCo LDHs integrated with flexible CNT/cotton fabric current collector, are realized by a facile method, which exhibits a high capacitance. Moreover, the hybrid electrode has been assembled into a flexible supercapacitor device with the cycling stability of 94% capacitance retention after 3000 cycles. The better flexibility and conductivity of the CNT, and highly intrinsic electrochemical activity of the NiCo LDHs as well as the superiority of the interwoven structure are responsible for the outstanding performance of the supercapacitor. The elaborate structural design can provide new insights into the construction of high-performance flexible supercapacitors. Figure 1

Flexible oxide neuromorphic transistors with synaptic learning functions

Realization of brain-inspired hardware devices is deemed to be a significant step for constructing a neuromorphic system. Moreover, flexible bioinspired neuromorphic devices have broad applications in bioinspired intelligent electronics. Here, we propose flexible IWO neuromorphic transistors gated with proton-conducting chitosan-based electrolytes. The transistor exhibits a low subthreshold swing of ~112 mV/dec and a high mobility of ~17 cm2 V−1 s−1. Moreover, the transistor exhibits excellent mechanical robustness against mechanical stress. Some crucial synaptic functions in biological synapses are mimicked on the proposed flexible transistor, including excitatory post-synaptic currents, paired-pulse facilitation, post-tetanic potentiation, etc. Most importantly, ‘learning-experience’ behaviors are implemented in the device. The proposed flexible neuromorphic devices have applications in artificial perception learning systems, including electronic skin and personal health monitoring.

Design of Helically Double-Leveled Gaps for Stretchable Fiber Strain Sensor with Ultralow Detection Limit, Broad Sensing Range, and High Repeatability.

Flexible strain sensors have attracted extensive attention in electronic skins and health monitoring systems. To date, it remains a great challenge for the development of a multifunctional strain sensor with simultaneous ultralow detection limit, broad sensing range, and high repeatability. In this paper, we report a new carbon nanotube/flexible fiber-shaped strain sensor. The fiber substrate has a novel microstructure where a highly elastic rubber fiber core is tightly wound by a continuous spring-like polypropylene fiber as the shell. Our sensor offers combined sensing performances of ultralow detection limit of 0.01% strain, wide sensing range of 200% strain, and high repeatability of 20 000 cycles by designing double-leveled helical gaps. This strain sensor shows a rapid response time of 70 ms under both stretching and releasing. In addition, it is available for a variety of other deformations such as bending and torsion. Due to the unique fiber structure, it can extend the torsion detection range to 1000 rad m-1. On the basis of the superior sensing performances, our sensor demonstrates to efficiently work for both subtle physiological activities and vigorous human motions. This work provides a general and effective strategy for designing smart wearable devices with high performance.

A Stretchable, Highly Sensitive, and Multimodal Mechanical Fabric Sensor Based on Electrospun Conductive Nanofiber Yarn for Wearable Electronics

AbstractThe development of highly sensitive, stretchable, and wearable electronic skin with multimodal mechanical‐sensing performance is of great research value for applications in health monitoring, and wearable electronic devices. In this work, a fabric‐like sensor with high flexibility and weavability that could detect the mechanical forces induced by pressure, strain, and flexion is designed. The fabric‐like sensor is woven by composite yarns (GCNF@ECYs) formed by winding graphene oxide‐doped polyacrylonitrile nanofiber yarns with in situ polymerized conductive polypyrrole on elastic yarns. The hierarchical structure of the fabric ranged from the macroscopic yarn to the submicron‐scale fibers to the nanometer‐scale particles as well as the wrapped structure constructed by winding conductive nanofiber yarn on elastic yarn. This offers more conductive pathways, larger deformation space, and multimodal mechanical‐sensing capabilities. The GCNF@ECY sensor unit has high sensitivity (the gauge factor was ≈68), wide pressure‐sensing range, excellent cycling stability, and good repeatability (over 10 000 cycles). The sensor can detect human respiration, facial expressions, pulse monitoring, and a full range of human motion. Moreover, the fabric sensor can be easily woven into textiles to produce electronic textiles with great potential in wearable human health monitoring electronics devices.

A fully enclosed, 3D printed, hybridized nanogenerator with flexible flux concentrator for harvesting diverse human biomechanical energy

Human body motion is highly regarded as a promising source of energy for powering body-worn electronic devices and health monitoring sensors. Transforming the human biomechanical energy into an electrical energy provides a sustainable energy to drive those devices and sensors, reducing their battery dependency. This work presents a fully-enclosed wrist-wearable hybridized electromagnetic-triboelectric nanogenerator (FEHN) for effectively scavenging energy from the low-frequency natural human wrist-motion (≤ 5 Hz). The FEHN incorporates the rolling electrostatic induction and electromagnetic induction using a freely moving magnetic ball inside a hollow circular tube. The materials used in 3D printing technology are used as energy harvesting material for easy, quick and worthwhile fabrication of the FEHN. A thin flexible flux concentrating material is introduced to increase the emf and enhances the electromagnetic output performance. The FEHN can harvest energy under the diverse circumstances and irregular wrist-motions, such as swinging, waving, shaking, etc. Following the experiments, the FEHN achieves an average power density of 0.118 mW cm−3 and can drive a commercial wrist-watch continuously for more than 23 min from just 5 s of wrist motion. This successful demonstration renders an effective approach for scavenging wasted biomechanical energy and provides a promising solution towards the development of sustainable power supply for wearable electronic devices and self-powered healthcare monitoring sensors.

NOS.E: A New Fast Response Electronic Nose Health Monitoring System.

We present a practical electronic nose (e-nose) sys-tem, NOS.E, for the rapid detection and identification of human health conditions. By detecting the changes in the composition of an individual's respiratory gases, which have been shown to be linked to changes in metabolism, e-nose systems can be used to characterize the physical health condition. We demonstrated our system's viability with a simple data set consists of breath collected under three different scenarios from one volunteer. Our preliminary results show the popular classifier SVM can discriminate NOS.E's responses under the three scenarios with high performance. In future work, we will aim to gather a more varied data set to test NOS.E's abilities.

Integration of Biomaterials into Sensors Based on Organic Thin-Film Transistors.

Sensors based on organic thin-film transistors (OTFTs) present various advantages, including high sensitivity and mechanical flexibility, thus possessing potential applications such as wearable devices and biomedical electronics for health monitoring, etc. However, such applications are partially limited by the biocompatibility, biodegradability, and sensitivity to target analytes of OTFT-based sensors, which can be improved by the incorporation of diverse biomaterials. This article presents a brief review from the viewpoint of the type of the integrated biomaterials, including naturally occurring biomacromolecules such as proteins, enzymes, and deoxyribonucleic acid, as well as biocompatible polymers such as polylactide, poly(lactide-co-glycolide), poly(ethylene glycol), cellulose, polydimethylsiloxane, parylene, etc. It is believed that future work in this field should be devoted to the selectivity, sensitivity, and stability improvement as well as the high-level integration and sophistication on the basis of the OTFT-based sensors for physical, chemical, and biological sensing applications.

Adopting Electronic Medical Record Systems and Health Monitoring Systems to Improve Health Care System in a National Cancer Institute

The appropriate use of state of the art technologies for health care service provision is of a great use and importance, not only for enhancing the patient’s health care but also for facilitating, automating and streamlining patient’s identification processes and record managements in the hospitals. According to the World Health Organization, hospitals nowadays are experiencing problems towards collecting, monitoring and management of health care data due to the fragmented structures and lack of regulation. In this study, the functioning and limitations of an existing healthcare software system were analysed with the development of an improved system to address the limitations. The study introduced the adaptation of both Electronic Medical Record System and Health Monitoring System, with the use of prototyping software development methodology; a justification for the chosen methodology is discussed. Among the critical elements of the health care systems analysed in this study includes schedule management, records management, patient care management and monitoring patient’s medication with a detailed description of each phase of the prototyping development methodology.

Electronic Health Monitoring System

Electronic Health Monitoring System

Flexible Bimodal Sensor for Simultaneous and Independent Perceiving of Pressure and Temperature Stimuli

AbstractSimultaneous bimodal perceiving of pressure and temperature stimuli is widely desired for artificial intelligence electronics, such as electronic skin and health monitoring. In multiparametric sensing, it is a challenge to detect different stimuli independently and expediently without cross coupling. Here, this study reports a pressure–temperature bimodal tactile sensor composed of two sinuous thermosensitive platinum (Pt) ribbons fabricated on a flexible polyimide substrate, which is covered by a porous elastomer membrane to provide a handy solution for multimodal detection. By operating two Pt ribbons in a constant temperature difference feedback circuit, the sensor implements simultaneous and independent detections of pressure and temperature stimuli automatically and efficiently. High sensitivity, lower detection limit, high resolution, good stability, and low hysteresis are achieved for dual parametric sensing. The sensor shows competence in health monitoring for bimodal perceiving of wrist pulse and artery temperature simultaneously and independently. The smart sensing design and self‐sustained circuit simplify the bimodal sensor, and thus provide a fast and expedient approach for multimodal sensation applications.

CVD growth of fingerprint-like patterned 3D graphene film for an ultrasensitive pressure sensor

With the rapid development of wearable devices, flexible pressure sensors with high sensitivity and wide workable range are highly desired. In nature, there are many well-adapted structures developed through natural selection, which inspired us for the design of biomimetic materials or devices. Particularly, human fingertip skin, where many epidermal ridges amplify external stimulations, might be a good example to imitate for highly sensitive sensors. In this work, based on unique chemical vapor depositions (CVD)-grown 3D graphene films that mimic the morphology of fingertip skin, we fabricated flexible pressure sensing membranes, which simultaneously showed a high sensitivity of 110 (kPa)−1 for 0–0.2 kPa and wide workable pressure range (up to 75 kPa). Hierarchical structured PDMS films molded from natural leaves were used as the supporting elastic films for the graphene films, which also contribute to the superior performance of the pressure sensors. The pressure sensor showed a low detection limit (0.2 Pa), fast response (< 30 ms), and excellent stability for more than 10,000 loading/unloading cycles. Based on these features, we demonstrated its applications in detecting tiny objects, sound, and human physiological signals, showing its potential in wearable electronics for health monitoring and human/machine interfaces.

Energy‐Autonomous, Flexible, and Transparent Tactile Skin

Tactile or electronic skin is needed to provide critical haptic perception to robots and amputees, as well as in wearable electronics for health monitoring and wellness applications. Energy autonomy of skin is a critical feature that would enable better portability and longer operation times. This study shows a novel structure, consisting of a transparent tactile sensitive layer based on single‐layer graphene, and a photovoltaic cell underneath as a building block for energy‐autonomous, flexible, and tactile skin. Transparency of the touch sensitive layer is considered a key feature to allow the photovoltaic cell to effectively harvest light. Moreover, ultralow power consumed by the sensitive layer (20 nW cm−2) further reduces the photovoltaic area required to drive the tactile skin. In addition to its energy autonomy, the fabricated skin is sensitive to touch, mainly because a transparent polymeric protective layer, spin‐coated on the sensor's active area, makes the coplanar capacitor sensitive to touch, detecting minimum pressures of 0.11 kPa with a uniform sensitivity of 4.3 Pa−1 along a broad pressure range. Finally, the tactile skin patches are integrated on a prosthetic hand, and the responses of the sensors for static and dynamic stimuli are evaluated by performing tasks, ranging from simple touching to grabbing of soft objects.

Flexible, Cuttable, and Self-Waterproof Bending Strain Sensors Using Microcracked Gold Nanofilms@Paper Substrate.

Rapid advances in functional sensing electronics place tremendous demands on innovation toward creative uses of versatile advanced materials and effective designs of device structures. Here, we first report a feasible and effective fabrication strategy to integrate commercial abrasive papers with microcracked gold (Au) nanofilms to construct cuttable and self-waterproof crack-based resistive bending strain sensors. Via introducing surface microstructures, the sensitivities of the bending strain sensors are greatly enhanced by 27 times than that of the sensors without surface microstructures, putting forward an alternative suggestion for other flexible electronics to improve their performances. Besides, the bending strain sensors also endow rapid response and relaxation time of 20 ms and ultrahigh stability of >18 000 strain loading-unloading cycles in conjunction with flexibility and robustness. In addition, the concepts of cuttability and self-waterproofness (attain and even surpass IPX-7) of the bending strain sensors have been demonstrated. Because of the distinctive sensing properties, flexibility, cuttability, and self-waterproofness, the bending strain sensors are attractive and promising for wearable electronic devices and smart health monitoring system.

Ultrasensitive Cracking-Assisted Strain Sensors Based on Silver Nanowires/Graphene Hybrid Particles.

Strain sensors with ultrahigh sensitivity under microstrain have numerous potential applications in heartbeat monitoring, pulsebeat detection, sound signal acquisition, and recognition. In this work, a two-part strain sensor (i.e., polyurethane part and brittle conductive hybrid particles layer on top) based on silver nanowires/graphene hybrid particles is developed via a simple coprecipitation, reduction, vacuum filtration, and casting process. Because of the nonuniform interface, weak interfacial bonding, and the hybrid particles' point-to-point conductive networks, the crack and overlap morphologies are successfully formed on the strain sensor after a prestretching; the crack-based stain sensor exhibits gauge factors as high as 20 (Δε < 0.3%), 1000 (0.3% < Δε < 0.5%), and 4000 (0.8% < Δε < 1%). In addition, we demonstrate the sensing mechanism under strain results in the high gauge factor of the strain sensor. Combined with its good response to bending, high strain resolution, and high working stability, the developed strain sensor is promising in the applications of electronic skins, motion sensors, and health monitoring sensors.