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Electrical interfacing with neural tissue is key to advancing diagnosis and therapies for neurological disorders, as well as providing detailed information about neural signals. A challenge for creating long‐term stable interfaces between electronics and neural tissue is the huge mechanical mismatch between the systems. So far, materials and fabrication processes have restricted the development of soft electrode grids able to combine high performance, long‐term stability, and high electrode density, aspects all essential for neural interfacing. Here, this challenge is addressed by developing a soft, high‐density, stretchable electrode grid based on an inert, high‐performance composite material comprising gold‐coated titanium dioxide nanowires embedded in a silicone matrix. The developed grid can resolve high spatiotemporal neural signals from the surface of the cortex in freely moving rats with stable neural recording quality and preserved electrode signal coherence during 3 months of implantation. Due to its flexible and stretchable nature, it is possible to minimize the size of the craniotomy required for placement, further reducing the level of invasiveness. The material and device technology presented herein have potential for a wide range of emerging biomedical applications.  相似文献   

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A simple cryo‐transfer method to fabricate ultrathin, stretchable, and conformal epidermal electrodes based on a combination of silver nanowires (AgNWs) network and elastomeric polymers is developed. This method can temporarily enable the soft elastomers with much higher elastic modulus and dimensional contraction through exploiting their glass‐transition behaviors. During this process, a much higher Von Mises stress can be loaded on AgNWs than usual, and the generated strong grip force can facilitate the complete transfer of AgNWs. Afterward, the thawed AgNWs and elastomer composites quickly recover to their soft state at room temperature. The obtained ultrathin and soft electrode with a thickness of 8.4 µm and transmittance of 90.8% at a sheet resistance of 13.2 Ω sq?1 can tolerate a stretching strain of 70% and 50 000 repeated bending cycles, which meets rigorous requirements of epidermal applications. The as‐prepared epidermal electrodes are effective and comfortable for electrophysiological signal monitoring, and while showing excellent performance exceeding the commercialized gel electrodes.  相似文献   

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Wearable devices have emerged as powerful tools for personalized healthcare in spite of some challenges that limit their widespread applicability as continuous monitors of physiological information. Here, a materials‐based strategy to add utility to traditional dielectric sensors by developing a conformal radiofrequency (RF) construct composed of an active layer encapsulated between two reverse‐facing split ring resonators is applied. These small (down to 2 mm × 2 mm) passive dielectric sensors possess enhanced sensitivity and can be further augmented by functionalization of this interlayer material. Demonstrator devices are shown where the interlayer is: (i) a porous silk film, and (ii) a modified PNIPAM hydrogel that swells with pH or temperature. In vivo use is demonstrated by adhesion of the device on tooth enamel to detect foods during human ingestion. Such sensors can be easily multiplexed and yield data‐rich temporal information during the diffusion of analytes within the trilayer structure. This format could be extended to a suite of interlayer materials for sensing devices of added use and specificity.  相似文献   

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Bioelectronic medicine can treat diseases and disorders in humans by electrically interfacing with peripheral nerves. Multielectrode cuffs can be used for selective stimulation of portions of the nerve, which is advantageous for treatment specificity. The biocompatibility and conformability of cuffs can be improved by reducing the mechanical mismatch between nerve tissue and cuffs, but selective stimulation of nerves has yet to be achieved with soft and stretchable cuff electrodes. Here, this paper reports the development of a soft and stretchable multielectrode cuff (sMEC) for selective nerve stimulation. The device is made of 50 µm thick silicone with embedded gold nanowire conductors, which renders it functional at 50% strain, and provides superior conformability for wrapping nerves. By using different stimulation protocols, high functional selectivity is achieved with the sMEC's eight stimulation electrodes in a porcine sciatic nerve model. Finite element modeling is used to predict the potential distribution within the nerve, which correlate well with the achieved stimulation results. Recent studies are showing that mechanical softness is of outermost importance for reducing foreign body response. It is therefore believed that the soft high-performance sMEC technology is ideal for future selective peripheral nerve interfaces for bioelectronic medicine.  相似文献   

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Owing to their compatibility with biology and large deformation, flexible electronics meet the demands for a wide range of applications that lie outside the capabilities of conventional rigid wafer‐based electronics. Devices such as solar cells, light‐emitting devices, touch screens, and wearable sensors have significantly advanced in recent years and changed human life. Flexible transparent electrodes are one of the most important components in flexible optoelectronic devices, collecting charges and transmitting light. Such electrodes based on silver nanowires (AgNWs), which exhibit superior mechanical flexibility, electrical and thermal conductivity, and optical transparency, are regarded as the most promising alternative to conventional indium tin oxide electrodes. However, some technical challenges, such as the uniformity and stability of AgNW networks, still exist and hinder the large‐scale commercialization of AgNW electrodes. Great efforts have been made in this field. A comprehensive survey of recent progress in flexible transparent AgNW electrodes in terms of performance criteria, material synthesis, fabrication process, performance enhancement, and future applications is provided. Finally, technical challenges and future trends are presented for the application of flexible transparent AgNW electrodes in flexible electronics.  相似文献   

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化学还原法合成均匀银纳米线的条件研究   总被引:1,自引:0,他引:1  
采用化学还原法,以乙二醇为还原剂,聚乙烯砒咯烷酮(PVP K30)为表面活性剂,通过还原硝酸银(AgNO3)溶液直接制备了高浓度的Ag纳米线溶液,并研究了PVP与AgNO3溶液摩尔浓度比和AgNO3溶液浓度对Ag纳米线生长的影响.用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对纳米Ag晶体的生长形貌进行了比较,利...  相似文献   

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Recent development of epidermal electronics provides an enabling means to continuous monitoring of physiological signals and close tracking of physical activities without affecting quality of life. Such devices require high sensitivity for low‐magnitude signal detection, noise reduction for motion artifacts, imperceptible wearability with long‐term comfortableness, and low‐cost production for scalable manufacturing. However, the existing epidermal pressure sensing devices, usually involving complex multilayer structures, have not fully addressed the aforementioned challenges. Here, the first epidermal–iontronic interface (EII) is successfully introduced incorporating both single‐sided iontronic devices and the skin itself as the pressure sensing architectures, allowing an ultrathin, flexible, and imperceptible packaging with conformal epidermal contact. Notably, utilizing skin as part of the EII sensor, high pressure sensitivity and high signal‐to‐noise ratios are achieved, along with ultralow motion artifacts for both internal (body) and external (environmental) mechanical stimuli. Monitoring of various vital signals, such as blood pressure waveforms, respiration waveforms, muscle activities and artificial tactile sensation, is successfully demonstrated, implicating a broad applicability of the EII devices for emerging wearable applications.  相似文献   

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As a potential alternative to indium oxide (ITO), metal nanowire transparent conductive electrodes (TCEs) have attracted more and more attention. Here, a facile method that can be applied to the synthesis of a variety of metal/bimetallic nanowires has been proposed. Metal/bimetallic nanowires synthesized through this method show high aspect ratios and great dispersibility, which makes them ideal building blocks for transparent electrodes. The synthesis mechanism is discussed in‐depth to give a theoretical basis of morphology control of metal nanostructures in organic synthesizing systems. TCEs with high flexibility, excellent optical–electrical performance as well as outstanding anti‐thermal and anti‐moisture stability are constructed. To the best of our knowledge, this is the first work on synthesizing multiple metal/bimetallic nanowires through one method.  相似文献   

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An electrocardiography (ECG) monitoring can be used to detect heart‐related abnormalities by recording cardiac activity over a period of time. The conventional 12‐lead ECG measurement system is the standard practice for the evaluation of the heart's electrical activity. However, a recent trend is to develop patch‐type measurement devices for unobtrusive ECG monitoring by reducing device size and number of electrodes on the skin. This development aims to minimize the discomfort for the user from the wearable recording devices. A printed, bandage‐type hybrid system for continuous ECG monitoring to allow as much comfort as possible while maintaining the signal quality required for medical evaluation is proposed. Movement artifacts in recorded ECG signals are a challenge in long‐term monitoring while the patients are engaged in their everyday activities. The movement artifacts from the printed skin‐conformable electrode are compared to commercial exercise stress‐test ECG electrodes during different physical activities and stationary periods. The results show that the signal quality obtained with the multilead patch ECG electrode, manufactured with printing technologies, is comparable to electrodes currently used in healthcare.  相似文献   

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Electronic textiles (e‐textiles) are in prime position to revolutionize the field of wearable electronics owing to their ubiquitous use and universal acceptance. However, mechanical incompatibility between the rigid conductive components on the soft textile platforms creates fragile e‐textile systems with poor electromechanical attributes. In this work, a novel design strategy to inkjet print reactive silver inks onto woven textiles with Kirigami‐inspired patterning to create e‐textiles with enhanced electromechanical features is introduced. By controlling the print processing and curing conditions, uniform conductive coatings with sheet resistances of 0.09 Ω sq−1 are achieved such that they do not interfere with the textiles innate flexibility, breathability, comfort, and fabric hand. The electromechanical coupling of the printed textiles shows a direct dependence on the anisotropic nature of the woven structures. Introducing Kirigami patterning creates robust devices that enhance and stabilize the electrical conductivity (ΔR/R0 < −20%) over large strain regimes (>150%). Furthermore, an electrocardiogram monitoring system fabricated from Kirigami e‐textiles exhibits stable signal acquisition under extreme deformations from arm joint flexion. The distinct properties of Kirigami patterning on e‐textiles enable unprecedented electromechanical performance in wearable textile electronics.  相似文献   

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Coating inkjet‐printed traces of silver nanoparticle (AgNP) ink with a thin layer of eutectic gallium indium (EGaIn) increases the electrical conductivity by six‐orders of magnitude and significantly improves tolerance to tensile strain. This enhancement is achieved through a room‐temperature “sintering” process in which the liquid‐phase EGaIn alloy binds the AgNP particles (≈100 nm diameter) to form a continuous conductive trace. Ultrathin and hydrographically transferrable electronics are produced by printing traces with a composition of AgNP‐Ga‐In on a 5 µm‐thick temporary tattoo paper. The printed circuit is flexible enough to remain functional when deformed and can support strains above 80% with modest electromechanical coupling (gauge factor ≈1). These mechanically robust thin‐film circuits are well suited for transfer to highly curved and nondevelopable 3D surfaces as well as skin and other soft deformable substrates. In contrast to other stretchable tattoo‐like electronics, the low‐cost processing steps introduced here eliminate the need for cleanroom fabrication and instead requires only a commercial desktop printer. Most significantly, it enables functionalities like “electronic tattoos” and 3D hydrographic transfer that have not been previously reported with EGaIn or EGaIn‐based biphasic electronics.  相似文献   

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