Wearable enzymatic biofuel cells would be the most prospective fuel cells for wearable devices because of their low cost, compactness and flexibility. As the high specificity and catalytic properties ...of enzymes, enzymatic biofuel cells (EBFCs) catalyze the fuel associated with the redox reaction and get electrical energy. Available biofuels such as glucose, lactate and pyruvate can be harvested from biofluids of sweat, tears and blood, which afford cells a favorable use in implantable and wearable devices. However, the development of wearable enzymatic biofuel cells requires significant improvements on the power density and enzymes lifetime. In this paper, some new advances in improving the performance of wearable enzymatic biofuel cells are reviewed based on the bioanode and biocathode by classifying single-enzyme and multi-enzyme catalysis system. Thereinto, the bioanode usually contains oxidases and dehydrogenases as catalyst, and the biocathode utilizes the catalysis of multi-copper oxidases (MCOs) in the single system. For further enhancing the power density, efforts to develop multi-enzyme catalysis strategies are discussed in bioanode and biocathode respectively. Moreover, some potential technologies in recent years, such as carbon nanodots, CNT sponges and mixed operational/storage electrode are summarized owing to notable efficiency and the capability of enhancing electron transfer on the electrode. Finally, major challenges and future prospects are discussed for the high power output, stable and practical wearable enzymatic biofuel cells.
•Progress for high power outputs and long lifetimes of wearable biofuel cells is reviewed from bioanode and biocathode.•Single-enzyme, multi-enzyme and other emerging materials are summarized for improving the wearable biofuel cell.•Major challenges and future prospects are discussed for the practical wearable enzymatic biofuel cells.
Peroxidases are widely used as catalysts in chemiluminescence (CL) reaction because of their excellent catalytic activity and various selectable species, such as horseradish peroxidase (HRP), sweet ...potato peroxidase (SPP) and soybean peroxidase (SbP). They have been employed in many different CL systems for the determination of hydrogen peroxidase (H2O2), nucleic acid, protein and so on. In this paper, the application of peroxidases in the most commonly used luminol-H2O2 CL system was reviewed from two aspects of horseradish peroxidase (HRP) and some anionic peroxidases. Thereinto, some enhancers used into HRP-catalyzed luminol-H2O2 CL system for higher sensitivity and lower detection limit were discussed according to their classification. The employment of some anionic peroxidases such as SPP and SbP in luminol-H2O2 CL system was also presented. The addition of some specific enhancers into anionic peroxidase catalyzed luminol-H2O2 system could lead to an increased light intensity and a relatively long-term stable signal. The mechanism of all these enhanced luminol-H2O2 CL reaction and the foundation of their analytical application were provided and reviewed in detail. Finally, combined with the magnetic beads or nanoparticles as well as other technologies, the characteristics of peroxidase-based luminol-H2O2 CL system were summarized.
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•The peroxidase-catalyzed luminol-H2O2 CL systems were reviewed according to the category of peroxidases.•The addition of enhancers into the CL systems improved the sensitivity and lowered the detection limit of the analytes.•Peroxidase-based CL systems contributed to the development of immunoassay with higher sensitivity and simpler device.
Abstract
Continuous monitoring of arterial blood pressure (BP) outside of a clinical setting is crucial for preventing and diagnosing hypertension related diseases. However, current continuous BP ...monitoring instruments suffer from either bulky systems or poor user-device interfacial performance, hampering their applications in continuous BP monitoring. Here, we report a thin, soft, miniaturized system (TSMS) that combines a conformal piezoelectric sensor array, an active pressure adaptation unit, a signal processing module, and an advanced machine learning method, to allow real wearable, continuous wireless monitoring of ambulatory artery BP. By optimizing the materials selection, control/sampling strategy, and system integration, the TSMS exhibits improved interfacial performance while maintaining Grade A level measurement accuracy. Initial trials on 87 volunteers and clinical tracking of two hypertension individuals prove the capability of the TSMS as a reliable BP measurement product, and its feasibility and practical usability in precise BP control and personalized diagnosis schemes development.
Recent advances in virtual reality (VR) technologies accelerate the creation of a flawless 3D virtual world to provide frontier social platform for human. Equally important to traditional visual, ...auditory and tactile sensations, olfaction exerts both physiological and psychological influences on humans. Here, we report a concept of skin-interfaced olfactory feedback systems with wirelessly, programmable capabilities based on arrays of flexible and miniaturized odor generators (OGs) for olfactory VR applications. By optimizing the materials selection, design layout, and power management, the OGs exhibit outstanding device performance in various aspects, from response rate, to odor concentration control, to long-term continuous operation, to high mechanical/electrical stability and to low power consumption. Representative demonstrations in 4D movie watching, smell message delivery, medical treatment, human emotion control and VR/AR based online teaching prove the great potential of the soft olfaction interface in various practical applications, including entertainment, education, human machine interfaces and so on.
Olfaction feedback systems could be utilized to stimulate human emotion, increase alertness, provide clinical therapy, and establish immersive virtual environments. Currently, the reported olfaction ...feedback technologies still face a host of formidable challenges, including human perceivable delay in odor manipulation, unwieldy dimensions, and limited number of odor supplies. Herein, we report a general strategy to solve these problems, which associates with a wearable, high-performance olfactory interface based on miniaturized odor generators (OGs) with advanced artificial intelligence (AI) algorithms. The OGs serve as the core technology of the intelligent olfactory interface, which exhibit milestone advances in millisecond-level response time, milliwatt-scale power consumption, and the miniaturized size. Empowered by robust AI algorithms, the olfactory interface shows its great potentials in latency-free mixed reality (MR) and fast olfaction enhancement, thereby establishing a bridge between electronics and users for broad applications ranging from entertainment, to education, to medical treatment, and to human machine interfaces.
Abstract
Thin, soft, and skin-integrated electronic system has great advantages for realizing continuous human healthcare monitoring. Here, we report an ultra-thin, flexible, and garment-based ...microelectronics powered by sweat-activated batteries (SABs) and applications of powering biosensors and microelectronic systems for real time sweat monitoring. The SAB cell is ultra-thin (1.25 mm) with excellent biocompatibility. The SAB has good electricity output with high capacity (14.33 mAh) and maximum power density (3.17 mW cm
−2
) after being activated by the sweat volume of 0.045 mL cm
−2
, which could continuously power 120 light emitting diodes over 3 h. The outputs could maintain stable after repeatable bending. Wireless microelectronics system could be continuously powered by the SABs for 3 h to monitor sweat and physiological information, including sweat Na
+
concentration, pH, and skin impedance. The reported integrated system provides a potential for solving the power issues of flexible wearable electronics and realizing personalized medicine.
Abstract
The rapid diagnosis of respiratory virus infection through breath and blow remains challenging. Here we develop a wireless, battery-free, multifunctional pathogenic infection diagnosis ...system (PIDS) for diagnosing SARS-CoV-2 infection and symptom severity by blow and breath within 110 s and 350 s, respectively. The accuracies reach to 100% and 92% for evaluating the infection and symptom severity of 42 participants, respectively. PIDS realizes simultaneous gaseous sample collection, biomarker identification, abnormal physical signs recording and machine learning analysis. We transform PIDS into other miniaturized wearable or portable electronic platforms that may widen the diagnostic modes at home, outdoors and public places. Collectively, we demonstrate a general-purpose technology for rapidly diagnosing respiratory pathogenic infection by breath and blow, alleviating the technical bottleneck of saliva and nasopharyngeal secretions. PIDS may serve as a complementary diagnostic tool for other point-of-care techniques and guide the symptomatic treatment of viral infections.
Vivid haptic feedback remains a challenge in truly immersive virtual reality and augmented reality. As the tactile sensitivity among different individuals and different parts of the hand within a ...person varies widely, a universal method to encode tactile information into faithful feedback in hands according to sensitivity features is urgently needed. In addition, existing haptic interfaces worn on the hand are usually bulky, rigid and tethered by cables, which is a hurdle for accurately and naturally providing haptic feedbacks. Here we report a soft, ultrathin, miniaturized and wireless electrotactile system (WeTac) that delivers current through the hand to induce tactile sensations as the skin-integrated haptic interface. With a relatively high pixel density over the whole hand area, the WeTac can provide tactile stimulation and measure the sensation thresholds of users in a flexible way. By mapping the thresholds for different electrical parameters, personalized threshold data can be acquired to reproduce virtual touching sensations on the hand with optimized stimulation intensity and avoid causing pain. With an accurate control of sensation level, temporal and spatial perception, it allows providing personalized feedback when users interact with virtual objects. This technique is promising for a more vivid touching experience in the virtual world and in human–machine interactions.The haptic interface is an essential part of human–machine interfaces where tactile information is delivered between human and machine. Yao et al. develop a soft, ultrathin, miniaturized and wireless electrotactile system that allows virtual tactile information to be reproduced over the hand.
Wearable electronics have attracted extensive attentions over the past few years for their potential applications in health monitoring based on continuous data collection and real‐time wireless ...transmission, which highlights the importance of portable powering technologies. Batteries are the most used power source for wearable electronics, but unfortunately, they consist of hazardous materials and are bulky, which limit their incorporation into the state‐of‐art skin‐integrated electronics. Sweat‐activated biocompatible batteries offer a new powering strategy for skin‐like electronics. However, the capacity of the reported sweat‐activated batteries (SABs) cannot support real‐time data collection and wireless transmission. Focused on this issue, soft, biocompatible, SABs are developed that can be directly integrated on skin with a record high capacity of 42.5 mAh and power density of 7.46 mW cm−2 among the wearable sweat and body fluids activated batteries. The high performance SABs enable powering electronic devices for a long‐term duration, for instance, continuously lighting 120 lighting emitting diodes (LEDs) for over 5 h, and also offers the capability of powering Bluetooth wireless operation for real‐time recording of physiological signals for over 6 h. Demonstrations of the SABs for powering microfluidic system based sweat sensors are realized in this work, allowing real‐time monitoring of pH, glucose, and Na+ in sweat.
A stretchable, conformable sweat‐activated battery (SAB) has been developed with high power density (7.46 mW cm−2) and energy capacity (42.5 mAh); it enables lighting 120 lighting emitting diodes (LEDs) for 5 h, and offers enough power to support Bluetooth wireless operation for real‐time recording of physiological signals in state‐of‐art wearable sensors for over 6 h. The SAB is also demonstrated in powering microfluidic system based sweat sensors for real‐time monitoring of pH, glucose, and Na+ in sweat.
A critical challenge lies in the development of the next‐generation neural interface, in mechanically tissue‐compatible fashion, that offer accurate, transient recording electrophysiological (EP) ...information and autonomous degradation after stable operation. Here, an ultrathin, lightweight, soft and multichannel neural interface is presented based on organic‐electrochemical‐transistor‐(OECT)‐based network, with capabilities of continuous high‐fidelity mapping of neural signals and biosafety active degrading after performing functions. Such platform yields a high spatiotemporal resolution of 1.42 ms and 20 µm, with signal‐to‐noise ratio up to ≈37 dB. The implantable OECT arrays can well establish stable functional neural interfaces, designed as fully biodegradable electronic platforms in vivo. Demonstrated applications of such OECT implants include real‐time monitoring of electrical activities from the cortical surface of rats under various conditions (e.g., narcosis, epileptic seizure, and electric stimuli) and electrocorticography mapping from 100 channels. This technology offers general applicability in neural interfaces, with great potential utility in treatment/diagnosis of neurological disorders.
The ultrasoft, multichannel, biodegradable OECT‐based neural interfaces are developed, which not only monitor the μ‐ECoG signals in high fidelity, but also autonomous degradation without any trigger events. Arrays with 100 channels, temporal/spatial resolution of 1.42 ms and 20 µm, and great signal‐to‐noise ratio of 37 dB, are achieved, demonstrating a facile and efficient tool for diagnostic purposes and neuroscience research.
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