Magnetoelastic effect characterizes the change of materials' magnetic properties under mechanical deformation, which is conventionally observed in some rigid metals or metal alloys. Here we show ...magnetoelastic effect can also exist in 1D soft fibers with stronger magnetomechanical coupling than that in traditional rigid counterparts. This effect is explained by a wavy chain model based on the magnetic dipole-dipole interaction and demagnetizing factor. To facilitate practical applications, we further invented a textile magnetoelastic generator (MEG), weaving the 1D soft fibers with conductive yarns to couple the observed magnetoelastic effect with magnetic induction, which paves a new way for biomechanical-to-electrical energy conversion with short-circuit current density of 0.63 mA cm
, internal impedance of 180 Ω, and intrinsic waterproofness. Textile MEG was demonstrated to convert the arterial pulse into electrical signals with a low detection limit of 0.05 kPa, even with heavy perspiration or in underwater situations without encapsulations.
The magnetoelastic effect-the variation of the magnetic properties of a material under mechanical stress-is usually observed in rigid alloys, whose mechanical modulus is significantly different from ...that of human tissues, thus limiting their use in bioelectronics applications. Here, we observed a giant magnetoelastic effect in a soft system based on micromagnets dispersed in a silicone matrix, reaching a magnetomechanical coupling factor indicating up to four times more enhancement than in rigid counterparts. The results are interpreted using a wavy chain model, showing how mechanical stress changes the micromagnets' spacing and dipole alignment, thus altering the magnetic field generated by the composite. Combined with liquid-metal coils patterned on polydimethylsiloxane working as a magnetic induction layer, the soft magnetoelastic composite is used for stretchable and water-resistant magnetoelastic generators adhering conformably to human skin. Such devices can be used as wearable or implantable power generators and biomedical sensors, opening alternative avenues for human-body-centred applications.
Recent advances in microfluidics, microelectronics, and electrochemical sensing methods have steered the way for the development of novel and potential wearable biosensors for healthcare monitoring. ...Wearable bioelectronics has received tremendous attention worldwide due to its great a potential for predictive medical modeling and allowing for personalized point-of-care-testing (POCT). They possess many appealing characteristics, for example, lightweight, flexibility, good stretchability, conformability, and low cost. These characteristics make wearable bioelectronics a promising platform for personalized devices. In this paper, we review recent progress in flexible and wearable sensors for non-invasive biomonitoring using sweat as the bio-fluid. Real-time and molecular-level monitoring of personal health states can be achieved with sweat-based or perspiration-based wearable biosensors. The suitability of sweat and its potential in healthcare monitoring, sweat extraction, and the challenges encountered in sweat-based analysis are summarized. The paper also discusses challenges that still hinder the full-fledged development of sweat-based wearables and presents the areas of future research.
Two-dimensional (2D) transition-metal nitrides just recently entered the research arena, but already offer a potential for high-rate energy storage, which is needed for portable/wearable electronics ...and many other applications. However, a lack of efficient and high-yield synthesis methods for 2D metal nitrides has been a major bottleneck for the manufacturing of those potentially very important materials, and only MoN, Ti4N3, and GaN have been reported so far. Here we report a scalable method that uses reduction of 2D hexagonal oxides in ammonia to produce 2D nitrides, such as MoN. MoN nanosheets with subnanometer thickness have been studied in depth. Both theoretical calculation and experiments demonstrate the metallic nature of 2D MoN. The hydrophilic restacked 2D MoN film exhibits a very high volumetric capacitance of 928 F cm–3 in sulfuric acid electrolyte with an excellent rate performance. We expect that the synthesis of metallic 2D MoN and two other nitrides (W2N and V2N) demonstrated here will provide an efficient way to expand the family of 2D materials and add many members with attractive properties.
Long-term, real-time, and comfortable epidermal electronics are of great practical importance for healthcare monitoring and human–machine interaction. However, traditional physiological signal ...monitoring confined by the specific clinical sites and unreliability of the epidermal electrodes leads to great restrictions on its application. Herein, we constructed a solution-processed submicron (down to 230 nm), free-standing, breathable sandwich-structured hybrid electrode composed of a silver nanowire network with a conductive polymer film, which is conformal, water-permeable, and noninvasive to the skin while achieving good signal acquisition ability. The free-standing hybrid electrode is prepared via an in situ capillary force lift-off process and can be transferred onto complex surfaces. The whole process is a complete solution process that facilitates large-area preparation and application. The light-weight hybrid electrodes exhibit high optical transmittance, high electrical conductivity, and high gas/ion permeability. When the hybrid electrodes are attached onto the skin, the imperceptible films show high conformality with low electrical impedance, thus exhibiting significantly improved electrocardiology and electromyogram signal monitoring performance compared to that of the commercial gel electrodes.
Over the past few years, the rapid development of tactile sensing technology has contributed significantly to the realization of intuitional touch control and intelligent human-machine interaction. ...Apart from physical touch or pressure sensing, proximity sensing as a complementary function can extend the detection mode of common single functional tactile sensors. In this work, we present a transparent, matrix-structure dual functional capacitive sensor which integrates the capability of proximity and pressure sensing in one device, and the excellent spatial resolution offered by the isolated response of capacitive pixels enables us to realize precise location identification of approaching objects and loaded pressure with fast response, high stability and high reversibility.
Since its outbreak in 2019, COVID‐19 becomes a pandemic, severely burdening the public healthcare systems and causing an economic burden. Thus, societies around the world are prioritizing a return to ...normal. However, fighting the recession could rekindle the pandemic owing to the lightning‐fast transmission rate of SARS‐CoV‐2. Furthermore, many of those who are infected remain asymptomatic for several days, leading to the increased possibility of unintended transmission of the virus. Thus, developing rigorous and universal testing technologies to continuously detect COVID‐19 for entire populations remains a critical challenge that needs to be overcome. Wearable respiratory sensors can monitor biomechanical signals such as the abnormities in respiratory rate and cough frequency caused by COVID‐19, as well as biochemical signals such as viral biomarkers from exhaled breaths. The point‐of‐care system enabled by advanced respiratory sensors is expected to promote better control of the pandemic by providing an accessible, continuous, widespread, noninvasive, and reliable solution for COVID‐19 diagnosis, monitoring, and management.
Wearable respiratory sensors can monitor biomechanical signals such as the abnormities in respiratory rate and cough frequency caused by COVID‐19, as well as biochemical signals such as virus biomarkers from exhaled breaths. The point‐of‐care system enabled by advanced wearable respiratory sensors is expected to promote better control of the pandemic by providing an accessible, continuous, widespread, noninvasive, and reliable solution for COVID‐19 diagnosis, monitoring, and management.
Thermoregulation has substantial implications for human health. Traditional central space heating and cooling systems are less efficient due to wasted energy spent on the entire building and ignore ...individual thermophysiological comfort. Emerging textiles based on innovations in materials chemistry and physics, nanoscience, and nanotechnology have now facilitated thermoregulation in a far more personalized and energy-saving manner. In this tutorial review, we discuss the latest technological advances in thermoregulatory textiles. First, we outline the basic mechanisms behind the physiological chemistry processes for both internal and external thermoregulation in the human body. Then, we systematically elaborate on typical smart passive and active thermoregulatory textiles considering current working mechanisms, materials engineering towards practical applications. In light of burgeoning commercial trends, we offer important insights into green chemistry for the sustainable development of smart thermoregulatory textiles. Prospectively, we propose an autonomous textile thermoregulation system that could intelligently provide personalized thermophysiological comfort in a self-adaptive manner in the era of Internet of Things (IoT). The discussion of interdisciplinary interactions of energy, environmental science, and nanotechnology in this review will further promote development of the thermoregulatory textile field in both academia and industry, ultimately realizing personalized thermoregulation and a sustainable energy future.
This article provides a fundamental understanding of the physiology of body thermoregulation and the advances in thermoregulatory textile technologies, and a perspective on future textiles for personalized thermoregulation.
An expanding elderly population and people with disabilities pose considerable challenges to the current healthcare system. As a practical technology that integrates systems and services, assistive ...physical therapy devices are essential to maintain or to improve an individual’s functioning and independence, thus promoting their well-being. Given technological advancements, core components of self-powered sensors and optimized machine-learning algorithms will play innovative roles in providing assistive services for unmet global needs. In this Perspective, we provide an overview of the latest developments in machine-learning-aided assistive physical therapy devices based on emerging self-powered sensing systems and a discussion of the challenges and opportunities in this field.
Wearable respiratory monitoring is a fast, non‐invasive, and convenient approach to provide early recognition of human health abnormalities like restrictive and obstructive lung diseases. Here, a ...computational fluid dynamics assisted on‐mask sensor network is reported, which can overcome different user facial contours and environmental interferences to collect highly accurate respiratory signals. Inspired by cribellate silk, Rayleigh‐instability‐induced spindle‐knot fibers are knitted for the fabrication of permeable and moisture‐proof textile triboelectric sensors that hold a decent signal‐to‐noise ratio of 51.2 dB, a response time of 0.28 s, and a sensitivity of 0.46 V kPa−1. With the assistance of deep learning, the on‐mask sensor network can realize the respiration pattern recognition with a classification accuracy up to 100%, showing great improvement over a single respiratory sensor. Additionally, a customized user‐friendly cellphone application is developed to connect the processed respiratory signals for real‐time data‐driven diagnosis and one‐click health data sharing with the clinicians. The deep‐learning‐assisted on‐mask sensor network opens a new avenue for personalized respiration management in the era of the Internet of Things.
Rayleigh‐instability‐induced spindle‐knot fibers are knitted for the fabrication of permeable and moisture‐proof textile triboelectric sensors. With the assistance of deep learning, the on‐mask sensor network can realize the respiration pattern recognition with a classification accuracy up to 100%. A customized cellphone application is developed to enable real‐time, user‐friendly, and personalized respiration management.
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