Small extracellular vesicles from young plasma reverse age-related functional declines by improving mitochondrial energy metabolism.

Recent investigations into heterochronic parabiosis have unveiled robust rejuvenating effects of young blood on aged tissues. However, the specific rejuvenating mechanisms remain incompletely elucidated. Here we demonstrate that small extracellular vesicles (sEVs) from the plasma of young mice counteract pre-existing aging at molecular, mitochondrial, cellular and physiological levels. Intravenous injection of young sEVs into aged mice extends their lifespan, mitigates senescent phenotypes and ameliorates age-associated functional declines in multiple tissues. Quantitative proteomic analyses identified substantial alterations in the proteomes of aged tissues after young sEV treatment, and these changes are closely associated with metabolic processes. Mechanistic investigations reveal that young sEVs stimulate PGC-1α expression in vitro and in vivo through their miRNA cargoes, thereby improving mitochondrial functions and mitigating mitochondrial deficits in aged tissues. Overall, this study demonstrates that young sEVs reverse degenerative changes and age-related dysfunction, at least in part, by stimulating PGC-1α expression and enhancing mitochondrial energy metabolism.

Incidence and Characteristics of Knee Ligament and Meniscal Injuries in Patients With Posterolateral Tibial Plateau Fractures.

Background: Anterior cruciate ligament (ACL) tears are commonly seen with concomitant injuries to the posterolateral tibial plateau, while the occurrence of ACL injuries in posterolateral tibial plateau fractures (PTPFs) remains unclear. Purpose: To (1) explore the incidence of knee ligament (anterior or posterior cruciate ligament, medial or lateral collateral ligament) and medial or lateral meniscus injuries in patients with PTPF and (2) find reliable PTPF-related parameters to predict the risk of knee ligament and meniscal injuries. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients diagnosed with PTPF who had computed tomography and magnetic resonance imaging (MRI) data were identified. Morphological parameters of the PTPF were measured on sagittal computed tomography images. Knee ligament and meniscal injuries were assessed using MRI. The association of ACL injuries with meniscal injuries was analyzed. Receiver operating characteristic (ROC) analysis was used to determine the value and cutoff point of the PTPF morphological parameters for diagnosing complete in-substance ACL tears. Results: Overall, 113 patients with PTPF were included. ACL injuries were present in 94 (83.2%) patients, including 43 (38.1%) avulsion fractures and 28 (24.8%) complete in-substance tears. Patients with in-substance ACL tears had a higher incidence of lateral meniscus posterior horn tears compared with the other patients (PBonferroni < .001). ROC analysis revealed that both the fracture depression angle (cutoff point, 25.5°) and the posterior articular surface loss percentage (cutoff point, 37.5%) had a sensitivity >90% and a specificity >80% for the diagnosis of complete in-substance ACL tears. Conclusion: ACL injuries were seen in 83.2% of the study patients. Complete in-substance ACL tears were associated with an increased incidence of lateral meniscus posterior horn tears. Among PTPF parameters, fracture depression angle and posterior articular surface loss percentage showed a high predictive value for the presence of complete in-substance ACL tears, thereby reducing delays in diagnosis and treatment.

Highly Enantioselective Catalysis by Enzyme Encapsulated in Metal Azolate Frameworks with Micelle-Controlled Pore Sizes.

Encapsulating enzymes within metal-organic frameworks has enhanced their structural stability and interface tunability for catalysis. However, the small apertures of the frameworks restrict their effectiveness to small organic molecules. Herein, we present a green strategy directed by visible linker micelles for the aqueous synthesis of MAF-6 that enables enzymes for the catalytic asymmetric synthesis of chiral molecules. Due to the large pore aperture (7.6 Å), double the aperture size of benchmark ZIF-8 (3.4 Å), MAF-6 allows encapsulated enzyme BCL to access larger substrates and do so faster. Through the optimization of surfactants' effect during synthesis, BCL@MAF-6-SDS (SDS = sodium dodecyl sulfate) displayed a catalytic efficiency (Kcat/Km) that was 420 times greater than that of BCL@ZIF-8. This biocomposite efficiently catalyzed the synthesis of drug precursor molecules with 94-99% enantioselectivity and nearly quantitative yields. These findings represent a deeper understanding of de novo synthetic encapsulation of enzyme in MOFs, thereby unfolding the great potential of enzyme@MAF catalysts for asymmetric synthesis of organics and pharmaceuticals.

Ultrathin Fe-MOFs modified by Fe9S10 for highly efficient oxygen evolution reaction.

Developing efficient and economical catalysts is essential for water splitting. The application of MOF catalysts in water splitting is limited by poor conductivity; however, the introduction of conductive TMS could enhance their activity. Herein, novel composite Fe9S10/Fe-MOF/NF-2 was constructed by introducing dendritic Fe9S10 onto the surface of a 2D ultrathin Fe-MOF. Composite catalysts elaborately utilize the structural and chemical advantages of MOF and TMS while improving the deficiencies of monomers through the combination. Owing to the optimal structure, the hybrid catalyst Fe9S10/Fe-MOF/NF-2 displayed better catalytic performance than bare Fe-MOFs and Fe9S10, with low overpotentials of 202 and 216 mV at 10 mA cm-2 in alkaline solution and simulated seawater, respectively. This work provides an innovative approach to modify MOFs as electrocatalysts for OER.

Soft Fiber/Textile Actuators: From Design Strategies to Diverse Applications.

Fiber/textile-based actuators have garnered considerable attention due to their distinctive attributes, encompassing higher degrees of freedom, intriguing deformations, and enhanced adaptability to complex structures. Recent studies highlight the development of advanced fibers and textiles, expanding the application scope of fiber/textile-based actuators across diverse emerging fields. Unlike sheet-like soft actuators, fibers/textiles with intricate structures exhibit versatile movements, such as contraction, coiling, bending, and folding, achieved through adjustable strain and stroke. In this review article, we provide a timely and comprehensive overview of fiber/textile actuators, including structures, fabrication methods, actuation principles, and applications. After discussing the hierarchical structure and deformation of the fiber/textile actuator, we discuss various spinning strategies, detailing the merits and drawbacks of each. Next, we present the actuation principles of fiber/fabric actuators, along with common external stimuli. In addition, we provide a summary of the emerging applications of fiber/textile actuators. Concluding with an assessment of existing challenges and future opportunities, this review aims to provide a valuable perspective on the enticing realm of fiber/textile-based actuators.

Biomechanical study of a new rim plate fixation strategy for two kinds of posterolateral depression patterns of tibial plateau fractures: a finite element analysis.

PURPOSE: The biomechanical capacity of "Barrel Hoop Plate (BHP)" in the treatment of the posterolateral tibial plateau (PL) depression fractures remains unknown. In this study, two kinds of posterolateral tibial plateau depression models involving mild slope-type depression fracture (MSDF) and local sink hole-type depression fracture (LSDF) were created to test and compare the biomechanical capacities of BHP with the other two conventional fixations (Anterolateral Plate and Posterolateral Plate, ALP and PLP) by finite element analysis. METHODS: The 3D models of three kinds of plate-screw systems and the two kinds of PL-depression models (MSDF and LSDF) were created. An axial force of 400N was applied from the distal femur to the tibial plateau. The maximal displacements of the posterolateral fractures (PLFs), the distribution on the PLFs articular surface and key points displacements were measured. Stresses in the fixation complex including the maximal Equivalent (von-Mises) Stress of implants, the max shear stress of PLFs and stiffness of the fixation were calculated. RESULTS: The maximal displacement of MSDF was least in Group BHP. The maximal displacement of LSDF was least in Group ALP. In MSDF, BHP showed the best rim fix effect in MSDF, but unsatisfactory results in LSDF. In both MSDF and LSDF, the greatest max Equivalent Stress of the plate and the screw occurred in the PLP system. ALP and BHP showed a comparable stiffness in MSDF and ALP had the strongest stiffness in the fixation of LSDF. CONCLUSIONS: In MSDF, the BHP has the best biomechanical capacity, especially in displacements of key points such as the PL rim, fracture line, and depression center. In LSDF, the ALP system shows the best biomechanical effect. Although the PLP has the best fixation effect on the posterior wall, it is not suitable for PL-depression fracture fixation.

Correlation between the rate of morphological changes and rupture of intracranial aneurysms during one cardiac cycle analyzed by 4D-CTA.

Objective: This study aimed to analyze the relationship between the rate of morphological changes and intracranial aneurysm rupture during the cardiac cycle. Methods: Eighty-four patients with intracranial aneurysms were retrospectively analyzed and divided into the rupture (42 cases) and unruptured (42 cases) groups. Four-dimensional computed tomography angiography (4D-CTA) was performed to collect quantitative parameters of aneurysm morphology and calculate the morphological change rate. The potential factors associated with aneurysm rupture were determined by comparing the general clinical data and rate of change in the location and morphology of the aneurysm between the two groups. Results: Each morphological change rate in the rupture group was generally higher than that of the unruptured group. The rate of dome height change and aneurysm volume change were independent factors associated with aneurysm rupture. ROC curve analysis revealed that the diagnostic accuracy of the aneurysm volume change rate was higher. When the volume change rate was 12.33%, the sensitivity and specificity of rupture were 90.5 and 55.8%, respectively. Conclusion: The rate of change in dome height and volume of intracranial aneurysms during one cardiac cycle were independent factors associated with aneurysm rupture.

An optical-based multipoint 3-axis pressure sensor with a flexible thin-film form.

Multipoint 3-axis tactile pressure sensing by a high-resolution and sensitive optical system provides rich information on surface pressure distribution and plays an important role in a variety of human interaction-related and robotics applications. However, the optical system usually has a bulky profile, which brings difficulties to sensor mounting and system integration. Here, we show a construction of thin-film and flexible multipoint 3-axis pressure sensor by optical methods. The sensor can detect the distribution of 3-axis pressure on an area of 3 centimeter by 4 centimeter, with a high-accuracy normal and tangential pressure sensing up to 360 and 100 kilopascal, respectively. A porous rubber is used as a 3-axis pressure-sensitive optical modulator to omit the thick and rigid focusing system without sacrificing the sensitivity. In addition, by integrating thin and flexible backlight and imager, the sensor has a total thickness of 1.5 milimeter, making it function properly even when bent to a radius of 18 milimeter.

PP2 alleviates the progression of osteoarthritis by inhibiting Wnt/ß-catenin and activating TGF-ß/Smad signaling.

OBJECTIVE: We aimed to explore the effect and mechanism of the Src inhibitor PP2 on osteoarthritis (OA) progression. METHODS: The protein expressions of Src, p-Src (y418) and p-FAK in normal and OA human chondrocytes were detected by immunofluorescence (IF) analysis. Chondrocytes from the femur and tibial plateau of 3-day-old mice were extracted and inoculated into 6-well plates. The chondrocytes were co-cultured with IL-1ß and different doses of PP2, and then the degeneration of extracellular matrix was analyzed. A mouse OA model was induced by destabilizing medial meniscectomy of the right knee. Two weeks after the operation, different doses of PP2 were injected intraperitoneally. The drug was given three times a week for 6 weeks, and then the mice were sacrificed. Histopathological, IF and immunoblotting analyses were used to detect key OA catabolic markers and protein expression and related signaling. RESULTS: The levels of Src, p-Src (y418) and p-FAK in the knee cartilage tissue of patients with OA were abnormally increased. After chondrocytes were co-treated with IL-1ß and different doses of PP2, the results showed that PP2 reduced the abnormal increase of ß-catenin, p-ß-catenin and other proteins induced by IL-1ß, and reversed the decrease of p-Smad3, aggrecan and collagen Ⅱ protein levels. Meanwhile, intraperitoneal injection of PP2 in vivo significantly reduced the degeneration of articular cartilage in the OA mouse model. CONCLUSION: Our data indicate that targeting Src with PP2 protected against cartilage destruction in an OA mouse model by inhibiting Wnt/ß-catenin and activating TGF-ß/Smad signaling, suggesting that Src may be a potential therapeutic target for OA treatment.

Highly selective photocatalytic CO2 reduction and hydrogen evolution facilitated by oxidation induced nitrogen vacancies on g-C3N4.

The introduction of nitrogen vacancies into polymeric carbon nitride (PCN) has been attested to be a reliable strategy to enhance photocatalytic performance. Nitrogen vacancies were considered as active sites to promote the adsorption of target molecules and capture photoexcited electrons to inhibit the recombination of charge pairs, accelerate photoinduced electrons to participate in photocatalytic reaction. In this paper, a series of PCN with rich nitrogen vacancies were prepared by etching of chromic acid solution. Sample 20KCSCN had the highest photocatalytic performance whose evolution efficiency of CO2 to CO and CH4 can reach 3.9 and 0.5 µmol·g-1·h-1, respectively. These evolution efficiencies are 2.9 and 4 times higher than that of the PCN. Meanwhile, 20KCSCN demonstrates high CO conversion selectivity and stability. The successful introduction of nitrogen vacancies not only increases the active sites of PCN surface, but also optimizes the optical structure, which dramatically boosts the separation of photoexcited charge pairs and the reduction capacity of photogenerated electrons. The enhancement mechanism for photocatalytic CO2 reduction performance of PCN was proposed. Besides, photocatalytic H2 evolution experiments were performed on all samples to confirm the universality of PCN photocatalytic activity enhancement etched by chromic acid solution. H2 evolution rate on 20KCSCN can reach 652 µmol·g-1·h-1, which is 1.6-fold higher than that on PCN (254 µmol·g-1·h-1) after 4 h irradiation under a 300 W Xe lamp. This work offers new venue for introducing nitrogen vacancies in PCN to regulate photoexcited charge pairs transfer. The photocatalytic enhancement of CO2 reduction could be used to alleviate the serious issue of excessive CO2 emission and energy crisis.

Introducing Bidirectional Axial Coordination into BiVO4 @Metal Phthalocyanine Core-Shell Photoanodes for Efficient Water Oxidation.

Core-shell photoanodes have shown great potential for photoelectrochemical (PEC) water oxidation. However, the construction of a high-quality interface between the core and shell, as well as a highly catalytic surface, remains a challenge. Herein, guided by computation, we present a BiVO4 photoanode coated with ZnCoFe polyphthalocyanine using pyrazine as a coordination agent. The bidirectional axial coordination of pyrazine plays a dual role by facilitating intimate interfacial contact between BiVO4 and ZnCoFe polyphthalocyanine, as well as regulating the electron density and spin configuration of metal sites in ZnCoFe phthalocyanine, thereby promoting the potential-limiting step of *OOH desorption. The resulting photoanode displayed a high photocurrent density of 5.7±0.1 mA cm-2 at 1.23 VRHE . This study introduces a new approach for constructing core-shell photoanodes, and uncovers the key role of pyrazine axial coordination in modulating the catalytic activity of metal phthalocyanine.

2D iron/cobalt metal-organic frameworks with an extended ligand for efficient oxygen evolution reaction.

The design of an efficient OER catalyst is significant for water splitting. Metal-organic frameworks (MOFs) are emerging as promising electrocatalysts due to their diversity of structure and tunability of function. In this paper, 2D FexCo1-x-MOF1/NF with an extended ligand (biphenyl-4,4'-dicarboxylic acid, BPDC) is constructed on nickel foam by a solvothermal method. Compared with the MOF2 synthesized by using BDC (1,4-bezenedicarboxylate), MOF1 shows excellent performance. Among MOF1, Fe0.5Co0.5-MOF1/NF exhibits outstanding performance with a low overpotential (217 mV) and a small Tafel slope (31.16 mV Dec-1) at 10 mA cm-2 and performs well at a high current density. In addition, the catalyst is remarkable in terms of durability both in alkaline solution and simulated seawater. The synergetic effect between Fe and Co and more active sites exposed play an important role in improving the OER activity. This work provides an effective strategy for the rational design of MOFs as inexpensive electrocatalysts.

Hydrogel fibers for wearable sensors and soft actuators.

Owing to superior softness, wetness, responsiveness, and biocompatibility, bulk hydrogels are being intensively investigated for versatile functions in devices and machines including sensors, actuators, optics, and coatings. The one-dimensional (1D) hydrogel fibers possess the metrics from both the hydrogel materials and structural topology, endowing them with extraordinary mechanical, sensing, breathable and weavable properties. As no comprehensive review has been reported for this nascent field, this article aims to provide an overview of hydrogel fibers for soft electronics and actuators. We first introduce the basic properties and measurement methods of hydrogel fibers, including mechanical, electrical, adhesive, and biocompatible properties. Then, typical manufacturing methods for 1D hydrogel fibers and fibrous films are discussed. Next, the recent progress of wearable sensors (e.g., strain, temperature, pH, and humidity) and actuators made from hydrogel fibers is discussed. We conclude with future perspectives on next-generation hydrogel fibers and the remaining challenges. The development of hydrogel fibers will not only provide an unparalleled one-dimensional characteristic, but also translate fundamental understanding of hydrogels into new application boundaries.

Immune regulation based on sex differences in ischemic stroke pathology.

Ischemic stroke is one of the world's leading causes of death and disability. It has been established that gender differences in stroke outcomes prevail, and the immune response after stroke is an important factor affecting patient outcomes. However, gender disparities lead to different immune metabolic tendencies closely related to immune regulation after stroke. The present review provides a comprehensive overview of the role and mechanism of immune regulation based on sex differences in ischemic stroke pathology.

Development of functional anti-Gn nanobodies specific for SFTSV based on next-generation sequencing and proteomics.

Severe fever with thrombocytopenia syndrome (SFTS) is an acute infectious disease caused by novel bunyavirus (SFTSV), with a mortality rate of 6.3% ~ 30%. To date, there is no specific treatment for SFTS. Previously, we demonstrated that SFTSV surface glycoprotein (Glycoprotein N, Gn) was a potential target for the development of SFTS vaccine or therapeutic antibodies, and anti-Gn neutralizing antibodies played a protective role in SFTS infection. Compared with traditional antibodies, nanobodies from camelids have various advantages, including small molecular weight, high affinity, low immunogenicity, convenient production by gene engineering, etc. In this study, we combined next-generation sequencing (NGS) with proteomics technology based on affinity purification-mass spectrometry (AP-MS) and bioinformatics analysis to high-throughput screen monoclonal anti-Gn nanobodies from camel immunized with Gn protein. We identified 19 anti-Gn monoclonal nanobody sequences, of which six sequences were selected for recombinant protein expression and purification. Among these six anti-Gn nanobodies, nanobody 57,493 was validated to be highly specific for Gn. The innovative high-throughput technical route developed in this study could also be expanded to the production of nanobodies specific for other viruses like SARS-CoV-2.

Pore Strategy Design of a Novel NiTi-Nb Biomedical Porous Scaffold Based on a Triply Periodic Minimal Surface.

The pore strategy is one of the important factors affecting the biomedical porous scaffold at the same porosity. In this work, porous scaffolds were designed based on the triply periodic minimal surface (TPMS) structure under the same porosity and different pore strategies (pore size and size continuous gradient distribution) and were successfully prepared using a novel Ni46.5Ti44.5Nb9 alloy and selective laser melting (SLM) technology. After that, the effects of the pore strategies on the microstructure, mechanical properties, and permeability of porous scaffolds were systematically investigated. The results showed that the Ni46.5Ti44.5Nb9 scaffolds have a low elastic modulus (0.80-1.05 GPa) and a high ductility (15.3-19.1%) compared with previous works. The pore size has little effect on their mechanical properties, but increasing the pore size significantly improves the permeability due to the decrease in specific surfaces. The continuous gradient distribution of the pore size changes the material distribution of the scaffold, and the smaller porosity structure has a better load-bearing capacity and contributes primarily to the high compression strength. The local high porosity structure bears more fluid flow, which can improve the permeability of the overall scaffold. This work can provide theoretical guidance for the design of porous scaffolds.

WO3 Photoanode with Predominant Exposure of {202} Facets for Enhanced Selective Oxidation of Glycerol to Glyceraldehyde.

The photoelectrocatalytic (PEC) oxidation of glycerol into highly value-added products is attractive, but it is extremely challenging to limit the oxidation products to the valuable C3 chemicals. The hole concentration and surface atomic arrangement of a photoanode can be modulated by controlling facet exposure, thus tuning the activity and selectivity. Herein, we report for the first time the formation of a WO3 photoanode with predominant exposure of {202} facets by a secondary hydrothermal method. The photoanode exhibits superior PEC glycerol conversion efficiency, giving an 80% selectivity to glyceraldehyde with a production rate of 462 mmol h-1 m-2. Also, the faraday efficiency for the C3 product reaches 98.6%. We made comparison between the {202} facets and the commonly studied {200} facets using experimental and theoretical methods. It is disclosed that the former enhances not only the adsorption and activation of glycerol via the terminal hydroxyl groups but also the desorption of glyceraldehyde.

On-skin paintable biogel for long-term high-fidelity electroencephalogram recording.

Long-term high-fidelity electroencephalogram (EEG) recordings are critical for clinical and brain science applications. Conductive liquid-like or solid-like wet interface materials have been conventionally used as reliable interfaces for EEG recording. However, because of their simplex liquid or solid phase, electrodes with them as interfaces confront inadequate dynamic adaptability to hairy scalp, which makes it challenging to maintain stable and efficient contact of electrodes with scalp for long-term EEG recording. Here, we develop an on-skin paintable conductive biogel that shows temperature-controlled reversible fluid-gel transition to address the abovementioned limitation. This phase transition endows the biogel with unique on-skin paintability and in situ gelatinization, establishing conformal contact and dynamic compliance of electrodes with hairy scalp. The biogel is demonstrated as an efficient interface for long-term high-quality EEG recording over several days and for the high-performance capture and classification of evoked potentials. The paintable biogel offers a biocompatible and long-term reliable interface for EEG-based systems.

Combustion Synthesis and Polymer Doping of Metal Oxides for High-Performance Electronic Circuitry.

ConspectusTransparent conducting oxides (TCOs) are inorganic electrical conductors with optical band gaps greater than 3.3 eV. TCOs have been extensively explored in functional windows, touch screen applications, transparent displays, solar cells, and even electronic circuits. Amorphous metal oxide (a-MO) semiconductors are a TCO class that has made impressive progress since the first 2004 demonstration of their utility as the semiconducting layer in thin-film transistors (TFTs). Their excellent counterintuitive electron mobilities in the amorphous state fill the performance gap between amorphous silicon and polysilicon, widening TFT applicability to high-value products such as high-resolution flat panel displays and emerging flexible/wearable electronics. The possibility of solution processing MO "inks" from air-stable precursors, via roll-to-roll and high-throughput printing, further expands their appeal. However, most MO TFTs fabricated using solution-processing require postdeposition film annealing at elevated temperatures (>400 °C) to ensure high-quality films and stable charge transport. Thus, MO fabrication on and TFT integration with inexpensive and typically temperature-sensitive flexible polymer substrates remains challenging, as does reducing MO processing times to those acceptable for high-throughput semiconductor circuit manufacture. Consequently, new MO film processing methodologies are being developed to meet these requirements. Among them, science-based combustion synthesis (CS) and polymer doping are promising complementary approaches to optimize materials quality and manufacturing efficiency; they are the topic of this Account.This Account summarizes the progress in CS and MO polymer doping research, made largely at Northwestern University over the past decade, to create high-performance MO TFTs. Regarding CS, we begin with an overview of combustion precursor chemistry that strongly affects the resulting film quality and device performance. Then, single fuel and dual fuel combustion syntheses for diverse MO systems are discussed. Representative examples highlight recent advances, with a focus on the relationship between (co)fuel-oxidizer types/amounts, thermal behavior, film microstructure, and TFT performance. Next, the discussion focuses on polymer doping of several MO matrices as a new approach to achieve semiconducting MO compositions with excellent performance and mechanical flexibility. Thus, the effect of the polymer architecture and content in the MO precursor formulations on the MO film composition, microstructure, electronic structure, and charge transport are discussed. The concluding remarks highlight challenges and emerging opportunities.

Robust, self-adhesive, reinforced polymeric nanofilms enabling gas-permeable dry electrodes for long-term application.

Robust polymeric nanofilms can be used to construct gas-permeable soft electronics that can directly adhere to soft biological tissue for continuous, long-term biosignal monitoring. However, it is challenging to fabricate gas-permeable dry electrodes that can self-adhere to the human skin and retain their functionality for long-term (>1 d) health monitoring. We have succeeded in developing an extraordinarily robust, self-adhesive, gas-permeable nanofilm with a thickness of only 95 nm. It exhibits an extremely high skin adhesion energy per unit area of 159 µJ/cm2 The nanofilm can self-adhere to the human skin by van der Waals forces alone, for 1 wk, without any adhesive materials or tapes. The nanofilm is ultradurable, and it can support liquids that are 79,000 times heavier than its own weight with a tensile stress of 7.82 MPa. The advantageous features of its thinness, self-adhesiveness, and robustness enable a gas-permeable dry electrode comprising of a nanofilm and an Au layer, resulting in a continuous monitoring of electrocardiogram signals with a high signal-to-noise ratio (34 dB) for 1 wk.