This report demonstrates a wearable elastomer‐based electronic skin including resistive sensors for monitoring finger articulation and capacitive tactile pressure sensors that register distributed ...pressure along the entire length of the finger. Pressure sensitivity in the order of 0.001 to 0.01 kPa−1 for pressures from 5 to 405 kPa, which includes much of the range of human physiological sensing, is achieved by implementing soft, compressible silicone foam as the dielectric and stretchable thin‐metal films. Integrating these sensors in a textile glove allows the decoupling of the strain and pressure cross‐sensitivity of the tactile sensors, enabling precise grasp analysis. The sensorized glove is implemented in a human‐in‐the‐loop system for controlling the grasp of objects, a critical step toward hand prosthesis with integrated sensing capabilities.
A multimodal electronic skin including resistive sensors for monitoring finger articulation and capacitive tactile pressure sensors is reported. Pressure sensitivity across much of the range of human physiological sensing is achieved by implementing soft, compressible silicone foam and stretchable thin metal films. A sensorized glove is implemented in a human‐in‐the‐loop system for controlling the grasp of objects.
With recent advancements in novel composite nanomaterials and microstructures, wearable electronic devices, particularly flexible and stretchable strain sensors, are receiving significant attention. ...This article reviews recent developments in composite-based flexible and stretchable strain sensors for wearable applications, such as those in healthcare and human motion detection, sports and physical training, soft robotics, and smart textiles. Material compositions and structures are categorically discussed based on their respective sensing mechanisms and novel structural interfaces. Four major categories of composites are reviewed in detail: carbon materials, nanowires (NWs) and nanoparticles (NPs), liquids, and newly emerging bio-hybrid nanocomposites. Parametric evaluations are conducted on the performance characteristics of these stretchable sensors, including those related to their respective composite interfaces. Potential applications of these high-performance strain sensors are discussed, along with the key technological challenges and future trends for improving sensor fabrication and performance.
Ambulatory measurements of trunk accelerations can provide valuable insight into the amount and quality of daily life activities. Such information has been used to create models to identify ...individuals at high risk of falls. However, external validation of such prediction models is lacking, yet crucial for clinical implementation. We externally validated 3 previously described fall prediction models. Complete questionnaires and 1-week trunk acceleration data were obtained from 263 community-dwelling people (mean age 71.8 years, 68.1% female). To validate models, we first used the coefficients and optimal cutoffs from the original cohort, then recalibrated the original models, as well as optimized parameters based on our new cohort. Among all participants, 39.9% experienced falls during a 6-month follow-up. All models showed poor precision (0.20-0.49), poor sensitivity (0.32-0.58), and good specificity (0.45-0.89). Calibration of the original models had limited effect on model performance. Using coefficients and cutoffs optimized on the external cohort also had limited benefits. Lastly, the odds ratios in our cohort were different from those in the original cohort, which indicated that gait characteristics, except for the index of harmonicity ML (medial-lateral direction), were not statistically associated with falls. Fall risk prediction in our cohort was not as effective as in the original cohort. Recalibration as well as optimized model parameters resulted in a limited increase in accuracy. Fall prediction models are highly specific to the cohort studied. This highlights the need for large representative cohorts, preferably with an external validation cohort.
Functional hydrogels have emerged as foundational materials in diagnostics, therapy, and wearable devices, owing to their high stretchability, flexibility, sensing, and outstanding biocompatibility. ...Their significance stems from their resemblance to biological tissue and their exceptional versatility in electrical, mechanical, and biofunctional engineering, positioning themselves as a bridge between living organisms and electronic systems, paving the way for the development of highly compatible, efficient, and stable interfaces. These multifaceted capability revolutionizes the essence of hydrogel-based wearable devices, distinguishing them from conventional biomedical devices in real-world practical applications. In this comprehensive review, we first discuss the fundamental chemistry of hydrogels, elucidating their distinct properties and functionalities. Subsequently, we examine the applications of these bioelectronics within the human body, unveiling their transformative potential in diagnostics, therapy, and human-machine interfaces (HMI) in real wearable bioelectronics. This exploration serves as a scientific compass for researchers navigating the interdisciplinary landscape of chemistry, materials science, and bioelectronics.
Functional hydrogels exhibit high stretchability, flexibility, and biocompatibility, making them ideal materials for diverse biowearable device applications.Their unique properties enable versatile engineering in electrical, mechanical, and biofunctional aspects, facilitating the creation of highly compatible interfaces.Functional hydrogels serve as a bridge between living organisms and electronic systems, revolutionizing wearable bioelectronics with enhanced compatibility and stability.Highlights the fundamental chemistry of functional hydrogels and explores their transformative potential in diagnostics, therapy, and human-machine interfaces within the human body in healthcare application. Display omitted
Wearable antennas have gained much attention in recent years due to their attractive features and possibilities in enabling lightweight, flexible, low cost, and portable wireless communication and ...sensing. Such antennas need to be conformal when used on different parts of the human body, thus need to be implemented using flexible materials and designed in a low profile structure. Ultimately, these antennas need to be capable of operating with minimum degradation in proximity to the human body. Such requirements render the design of wearable antennas challenging, especially when considering aspects such as their size compactness, effects of structural deformation and coupling to the body, and fabrication complexity and accuracy. Despite slight variations in severity according to applications, most of these issues exist in the context of body-worn implementation. This review aims to present different challenges and issues in designing wearable antennas, their material selection, and fabrication techniques. More importantly, recent innovative methods in back radiations reduction techniques, circular polarization (CP) generation methods, dual polarization techniques, and providing additional robustness against environmental effects are first presented. This is followed by a discussion of innovative features and their respective methods in alleviating these issues recently proposed by the scientific community researching in this field.
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•Masked spray deposition enables thick, free-standing electrodes for M-ZSCs.•M-ZSC achieves an ultrahigh areal capacitance of 226.5 mF/cm2 and an energy density of 80.5430 ...µWh/cm2.•M-ZSC is adaptable for deployment in flexible electronics and on-chip applications.•M-ZSC exhibits a remarkable 95% capacitance retention and stable performance over time.
The ubiquity of conventional micro-fabrication techniques has encountered impediments in constructing cost-effective micro-devices, thereby constraining their broad deployment. Concurrently, the suboptimal energy density inherent to supercapacitors exacerbates this challenge. This study presents a straightforward assembly methodology for the fabrication of a mechano-electrochemically efficient micro-zinc ion hybrid supercapacitor (M−ZSC), alongside the introduction of an innovative polymeric current collector. The M−ZSC is fabricated through a process involving masked spray deposition of a novel adhesive current collector and the electrode materials, and electroplating of zinc nanosheets onto the anode finger, creating an electrochemically performant and mechanically robust device. The resulting M−ZSC exhibits a notable areal capacitance of 52.2 mF/cm2 and an energy density of 18.5 µWh/cm2 for the normal mass-loading of 3.6 mg/cm2, which is amongst the highest reported values for energy storage. The masked spray deposition/hot pressing technique enabled us to fabricate free-standing thick electrodes with a loading density of up to 56.1 mg/cm2, facilitating the achievement of an ultrahigh areal capacitance of 227 mF/cm2 and an energy density of 80.5 µWh/cm2. Furthermore, the M−ZSC exhibits a robust retention of 95 % capacitance at 1 mA/cm2. Critical to its flexibility, the device is constructed using purely additive deposition methods on flexible substrates and is therefore well-tailored for deployment in flexible electronics and on-chip applications. These micro-devices are well-poised for seamless integration within a singular electronics package or chip architecture.
Power costs increasing, environmental pollution and global warming are issues that we are dealing with in the present time. To reduce their effects, scientists are focusing on improving energy ...harvesting-based power generators. Thermoelectric generators (TEGs) have demonstrated their ability to directly convert thermal energy into an electrical one via the Seebeck effect. Also, they are environmentally friendly because they do not contain chemical products, they operate silently because they do not have mechanical structures and/or moving parts, and they can be fabricated on many types of substrates like silicon, polymers, and ceramics. Furthermore, TEGs are position-independent, present a long operating lifetime and are suitable for integration into bulk and flexible devices. This paper presents in-depth analysis of TEGs, starting by an extensive description of their working principle, types (planar, vertical and mixed), used materials, figure of merit, improvement techniques including different thermoelectric materials arrangement (conventional, segmented and cascaded), and used technologies and substrates types (silicon, ceramics and polymers). This manuscript also describes the exploitation of TEGs in various fields starting from low-power applications (medical and wearable devices, IoT: internet of things, and WSN: wireless sensor network) to high-power applications (industrial electronics, automotive engines, and aerospace).
•TEGs efficiency and characteristics as Environmentally-friendly converters.•TEGs technologies, materials and improvement techniques.•TEGs used in low-power applications (medical, wearable devices, IoT and WSNs).•TEGs used in high-power applications (electronics, automotive and aerospace).
Electrochemical sensors are powerful analytical tools that, in the last few years, have attracted tremendous attention in coupling with wearable devices due to their incomparable properties, such as ...instrumental simplicity, low cost, flexibility, and miniaturization. These outstanding characteristics fit with the desired features for continuous on-body analyses. Wearable electrochemical sensors enable obtaining insights into individuals' health status through the noninvasive monitoring of clinically relevant biomarkers in different biofluids (saliva, tears, sweat, and interstitial fluids) without complex manipulation, sampling, and treatment steps. The electrochemical system can be fabricated in different substrates and transferred to the human body or coupled to common utensils to monitor (bio)chemical species or potentially hazardous compounds surrounding the users without disturbing their usual activities. In this work, we critically review the recent advances, the main technological and chemical challenges identified in wearable electrochemical sensors for forensic and clinical applications, highlighting the remarkable trends, needs, and challenges for future studies.
•Relevant wearable electrochemical sensors (WES) over the last five years are reviewed.•Main fabrication methods and strategies used in WES are presented.•Clinical and forensic applications are critically discussed.•Prospects and challenges towards real-time on-body analyses are described.•Recent advances, main technological and chemical challenges identified in WES applied for forensic sciences.
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