Flexible,high-density,laminated ECoG electrode array for high spatiotemporal resolution foci diagnostic localization of refractory epilepsy

High spatiotemporal resolution brain electrical signals are critical for basic neuroscience research and high-precision focus diagnostic localization,as the spatial scale of some pathologic signals is at the submillimeter or micrometer level.This entails connecting hundreds or thousands of electrode wires on a limited surface.This study reported a class of flexible,ultrathin,highdensity electrocorticogram(ECoG)electrode arrays.The challenge of a large number of wiring arrangements was overcome by a laminated structure design and processing technology improvement.The flexible,ultrathin,high-density ECoG electrode array was conformably attached to the cortex for reliable,high spatial resolution electrophysiologic recordings.The minimum spacing between electrodes was 15μm,comparable to the diameter of a single neuron.Eight hundred electrodes were prepared with an electrode density of 4444 mm^(-2).In focal epilepsy surgery,the flexible,high-density,laminated ECoG electrode array with 36 electrodes was applied to collect epileptic spike waves inrabbits,improving the positioning accuracy of epilepsy lesions from the centimeter to the submillimeter level.The flexible,high-density,laminated ECoG electrode array has potential clinical applications in intractable epilepsy and other neurologic diseases requiring high-precision electroencephalogram acquisition.

Experimental study of solid-liquid origami composite structures with improved impact resistance

In this paper,a liquid-solid origami composite design is proposed for the improvement of impact resistance.Employing this design strategy,Kresling origami composite structures with different fillings were designed and fabricated,namely air,water,and shear thickening fluid(STF).Quasi-static compression and drop-weight impact experiments were carried out to compare and reveal the static and dynamic mechanical behavior of these structures.The results from drop-weight impact experiments demonstrated that the solid-liquid Kresling origami composite structures exhibited superior yield strength and reduced peak force when compared to their empty counterparts.Notably,the Kresling origami structures filled with STF exhibited significantly heightened yield strength and reduced peak force.For example,at an impact velocity of 3 m/s,the yield strength of single-layer STF-filled Kresling origami structures increased by 772.7%and the peak force decreased by 68.6%.This liquid-solid origami composite design holds the potential to advance the application of origami structures in critical areas such as aerospace,intelligent protection and other important fields.The demonstrated improvements in impact resistance underscore the practical viability of this approach in enhancing structural performance for a range of applications.

Liquid metal as an efficient protective layer for lithium metal anodes in all-solid-state batteries

Lithium metal batteries with inorganic solid-state electrolytes have emerged as strong and attractive candidates for electrochemical energy storage devices because of their high-energy content and safety.Nonetheless,inherent challenges of deleterious lithium dendrite growth and poor interfacial stability hinder their commercial application.Herein,we report a liquid metal-coated lithium metal(LM@Li)anode strategy to improve the contact between lithium metal and a Li6PS5Cl inorganic electrolyte.The LM@Li symmetric cell shows over 1000 h of stable lithium plating/stripping cycles at 2mA cm^(-2) and a significantly higher critical current density of 9.8 mAcm^(-2) at 25°C.In addition,a full battery assembled with a high-capacity composite LiNbO3@-LiNi_(0.7)Co_(0.2)Mn_(0.1)O_(2)(LNO@NCM721)cathode shows stable cycling performance.Experimental and computational results have demonstrated that dendrite growth tolerance and physical contact in solid-state batteries can be reinforced by using LM interlayers for interfacial modification.

Integration of flexible,recyclable,and transient gelatin hydrogels toward multifunctional electronics

Facing the challenges posed by exponentially increasing e-waste,the development of recyclable and tran-sient electronics has paved the way to an environmentally-friendly progression strategy,where electron-ics can disintegrate and/or degrade into eco-friendly end products in a controlled way.Natural polymers possess cost and energy efficiency,easy modification,and fast degradation,all of which are ideal prop-erties for transient electronics.Gelatin is especially attractive due to its unique thermoreversible gelation processes,yet its huge potential as a multifunctional electronic material has not been well-researched due to its limited mechanical strength and low conductivity.Herein,we explored versatile applications of gelatin-based hydrogels through the assistance of multifunctional additives like carbon nanotubes to enhance their electromechanical performances.The optimized gelatin hydrogel displays not only a high conductivity of 0.93 S/m,electromagnetic shielding effectiveness of 39.6 dB,and tensile stress tolerance of 263 kPa,but also shows a negative permittivity phenomenon,which may find versatile applications in novel electronics.As a proof of concept,hydrogels were assembled as wearable sensors to sensitively de-tect static and dynamic pressures and strains generated by solids,liquids,and airflow,as well as diverse body movements.Furthermore,the recyclability,biocompatibility,and degradability of gelatin-based hy-drogels were well studied and analyzed.This work outlines a facile method to design multifunctional transient materials for wearable,sustainable,and eco-friendly electronics.

Recent progress in MOFs-based nanozymes for biosensing

Nanozymes are nanomaterials with enzyme-mimicking catalytic activity.Compared to natural enzymes,nanozymes show various properties such as easy to manufacture,stable,adjustable,and inexpensive.Nanozymes play key roles in biosensing,biocatalysis,and disease treatment.As an important kind of nanozymes,metal-organic framework(MOF)-based nanozymes are receiving a lot of attention due to their structural properties and composition.Rationally developing MOF with enzymes-like catalytic properties has opened new perspectives in biosensing.This review summarizes the up-to-date developments in synthesizing two-dimensional and three-dimensional MOF-based nanozymes and their applications in biosensing.Firstly,classification of nanozymes obtained by MOFs is categorized,and different properties of MOF-based nanozymes are described.Then,the distinctive applications of MOF-based nanozymes in identifying various analytes are thoroughly summarized.Finally,the recent challenges and progressive directions in this area are highlighted.

In-situ oriented oxygen-defect-rich Mn-N-O via nitridation and electrochemical oxidation based on industrial-scale Mn_(2)O_(3) to achieve high-performance aqueous zinc ion battery

As a general problem in the field of batteries,materials produced on a large industrial scale usually possess unsatisfactory electrochemical performances.Among them,manganese-based aqueous rechargeable zinc-ion batteries(ARZBs)have been emerging as promising large-scale energy storage systems owing to their high energy densities,low manufacturing cost and intrinsic high safety.However,the direct application of industrial-scale Mn2O3(MO)cathode exhibits poor electrochemical performance especially at high current rates.Herein,a highly reversible Mn-based cathode is developed from the industrial-scale MO by nitridation and following electrochemical oxidation,which triples the ion diffusion rate and greatly promotes the charge transfer.Notably,the cathode delivers a capacity of 161 m Ah g^(-1) at a high current density of 10 A g^(-1),nearly-three times the capacity of pristine MO(60 m Ah g^(-1)).Impressive specific capacity(243.4 m Ah g^(-1))is obtained without Mn^(2+) additive added in the electrolyte,much superior to the pristine MO(124.5 m Ah g^(-1)),suggesting its enhanced reaction kinetics and structural stability.In addition,it possesses an outstanding energy output of 368.4 Wh kg^(-1) at 387.8 W kg^(-1),which exceeds many of reported cathodes in ARZBs,providing new opportunities for the large-scale application of highperformance and low-cost ARZBs.

Alignment of inertialess spheroidal particles in flow-structure-dominated regions of turbulent channel flow:shape effect

The alignment of elongated fibers and thin disks is known to be significantly influenced by the presence of fluid coherent structures in near-wall turbulence(Cui et al.2021).However,this earlier study is confined to the spheroids with infinitely large or small aspect ratio,and the shape effect of finite aspect ratio on the alignment is not considered.The current study investigates the shape-dependent alignment of inertialess spheroids in structure-dominated regions of channel flow.With utilizing an ensemble-averaged approach for identifying the structure-dominated regions,we analyze the eigensystem of the linear term matrix in the Jeffery equation,which is governed by both particle shape and local fluid velocity gradients.In contrast to earlier conventional analysis based on local vorticity and strain rate,our findings demonstrate that the eigensystem of the Jeffery equation offers a convenient,effective,and universal framework for predicting the alignment behavior of inertialess spheroids in turbulent flows.By leveraging the eigensystem of the Jeffery equation,we uncover a diverse effect of fluid coherent structures on spheroid alignment with different particle shapes.Furthermore,we provide explanations for both shape-independent alignments observed in vortical-core regions and shape-dependent alignments around near-wall streamwise vortices.

Additively Manufactured Flexible Electronics with Ultrabroad Range and High Sensitivity for Multiple Physiological Signals'Detection

Flexible electronics can be seamlessly attached to human skin and used for various purposes, such as pulse monitoring, pressure measurement, tensile sensing, and motion detection. Despite their broad applications, most flexible electronics do not possess both high sensitivity and wide detection range simultaneously;their sensitivity drops rapidly when they are subjected to even just medium pressure. In this study, ultrabroad-range, high-sensitivity flexible electronics are fabricated through additive manufacturing to address this issue. The key to possess high sensitivity and a wide detection range simultaneously is to fabricate flexible electronics with large depth-width ratio circuit channels using the additive manufacturing inner-rinsing template method. These electronics exhibit an unprecedented high sensitivity of 320 kPa^(−1) over the whole detection range, which ranges from 0.3 to 30,000 Pa (five orders of magnitude). Their minimum detectable weight is 0.02 g (the weight of a fly), which is comparable with human skin. They can stretch to over 500% strain without breaking and show no tensile fatigue after 1000 repetitions of stretching to 100% strain. A highly sensitive and flexible electronic epidermal pulse monitor is fabricated to detect multiple physiological signals, such as pulse signal, breathing rhythm, and real-time beat-to-beat cuffless blood pressure. All of these signals can be obtained simultaneously for detailed health detection and monitoring. The fabrication method does not involve complex expensive equipment or complicated operational processes, so it is especially suitable for the fabrication of large-area, complex flexible electronics. We believe this approach will pave the way for the application of flexible electronics in biomedical detection and health monitoring.

Ultra-sensitive and wide applicable strain sensor enabled by carbon nanofibers with dual alignment for human machine interfaces

Flexible strain sensors with high sensitivity,wide detection range,and low detection limit have continuously attracted great interest due to their tremendous application potential in areas such as health/medical-care,human-machine interface,as well as safety and security.While both of a high sensitivity and a wide working range are desired key parameters for a strain sensor,they are usually contrary to each other to be achieved on the same sensor due to the tightly structure dependence of both of them.Here,a flexible strain sensor with both high sensitivity and wide strain detection range is prepared based on the design of an integrated membrane containing both of parallel aligned and randomly aligned carbon nanofibers(CNFs).The parallel aligned CNF membrane(p-CNF)exhibits a low strain detection limit and high sensitivity,while the random aligned CNF membrane(r-CNF)exhibits a large strain detection range.Taking the advantages of both p-CNF and r-CNF,the strain sensor with stacked p-CNF and r-CNF(p/r-CNF)exhibits both high sensitivity and wide working range.Its gauge factor(GF)is 1,272 for strains under 0.5%and 2,266 for strain from 70%to 100%.At the same time,it can work in a wide strain range of 0.005%to 100%,fulfilling the requirements for accurately detecting full-range human motions.We demonstrated its applications in the recognition of facial expressions and joint movements.Furtherly,we constructed an intelligent lip-language recognition system,which can accurately track phonetic symbols and may help people with language disabilities,proving the potential of this strain sensor in health management and medical assistance.Besides,we foresee that the dual-alignment structure design of the p/r-CNF strain sensor may also be applied in the design of other high performance sensors.

Design and optical performance investigation of all-sprayable ultrablack coating

Although ultrablack surfaces are urgently needed in wide applications owing to their extremely low reflectance over a broadband wavelength,obtaining simultaneously the ultrablackness and mechanical robustness by simple process technique is still a great challenge.Herein,by decoupling different light extinction effects to different layers of coating,we design an ultrablack coating that is all-sprayable in whole process.This coating presents low reflectance over visible–mid-infrared(VIS–MIR)wavelength(av.R≈1%in VIS),low multi-angle scattering(bidirectional reflection distribution function(BRDF)=10-2–10-3 sr-1),together with good substrate adhesion grade and self-cleaning ability,which are superior to most reported sprayable ultrablack surfaces.The light extinction effects of each layer are discussed.This method is also applicable in other material systems.

Probability-Based Analyses of the Snap-Through in Cage-Shaped Mesostructures Under Out-of-Plane Compressions

Three-dimensional(3D)mesostructures with distinct compressive deformation behaviors and tunable mechanical responses have gained increasing interest in recent years.3D cage-shaped mesostructures are representative framework structures widely exploited in 3D flexible electronics,owing to their unique cellular geometry and unusual mechanical responses.The snap-through behavior of cage-shaped mesostructures could potentially result in the performance degradation of electronics,while it could also be harnessed to design reconfigurable electronics.Due to the complicated deformation modes and random characteristics in experiments,the snap-through behavior of cage-shaped mesostructures remains largely unexplored,espe-cially in terms of probability-based analyses.In this work,we present a systematic study on the configuration evolution and snap-through of 3D cage-shaped mesostructures under out-of-plane compressions.Experimental and computational studies show the existence of two distinct deformation modes associated with the snap-through,which is controlled by the energy barrier based on the energetic analyses.Phase diagrams of the deformation modes decode how key geometric parameters and assembly strain affect the snap-through.Compressive experiments based on periodic arrays(10 × 10)of mesostructures provided a large amount of deformation data,allowing for statistical analyses of the snap-through behavior.These results provide new insights and useful guidelines for the design of 3D reconfigurable devices and multistable metamaterials based on 3D cage-shaped mesostructures.

CuS Electrode for All-pH Electrolyte in Aqueous Batteries

With their excellent safety, affordability, environmental friendliness and high ionic conductivity, aqueous batteries are prospective contenders to replace lithium-ion batteries. However, the pH of aqueous electrolyte might impact the battery’s electrochemical performance and even its normal operation. It is critical to develop an electrode that can work in different pH settings. The hydrothermal method and vulcanization treatment were used to successfully create copper sulfide(CuS) nanosheet in this work. It can store and transport nonmetal and metal ions as well as polyvalent ions with a high charge radius ratio, and function normally under a variety of pH conditions. The CuS electrode has a considerable capacity(900 mA·h/g) and rate performance under alkaline conditions, as well as an ultra-long discharge platform, which contribute to 80% of the total capacity.

High-Performance Recyclable Furan-based Epoxy Resin and Its Carbon Fiber Composites with Dense Hydrogen Bonding

The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of society.Since the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine solution.This study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.

一体化可拉伸的多功能电化学传感纤维构建微量汗液健康监测织物

透气舒适的传感纺织品可以检测人体汗液中的多种生物标记物,是在日常生活中实现全面健康监测的有效途径.然而,目前的可穿戴柔性电化学纺织品缺乏伸展性,这可能会导致信号不稳定或在移动过程中损坏设备.此外,这些纺织品对多种指示器的集成度有限,需要较大的表面积和大量的汗液来激活传感器.在此,我们报告了一种一体化多功能电化学生物传感器纤维,该纤维具有可拉伸性,通过微量汗液即可检测汗液中的多种生物标志物.这种生物传感器是通过将多功能碳纳米管条带以螺旋状排列的方式负载在预先拉伸的聚合物纤维芯上从而充当微电极,并且两者之间具有稳定界面.此外,通过引入超亲水鞘层,提高了生物传感器的汗液捕获效率.该生物传感器能够同时监测pH、K^(+)、Na^(+)、葡萄糖、乳酸和尿酸六种生物标记物,300%的应变下表现出稳定的传感性能.仅需1μL的汗液即可启动对六种生物标记物进行高效检测.由此编织的织物传感系统可以连续、实时地监测多种生物标记信息,从而完成人体健康状况的评估.

Promising thermal photonic management materials for sustainable human habitat

The spectral characteristics of outdoor structures,such as automobiles,buildings,and clothing,determine their energy interaction with the environment,from broad-spectrum absorption of light energy to high-efficiency thermal emission.Recently developed spectrally selective absorption(SSA)materials permit the reduction of energy loss from human habitat eco-system in the sustainable way and further reduce the utilization of fossil energy to achieve carbon neutrality.Here we review recent advances in SSA materials that enable rational and efficient management of thermal energy and provide new solutions for the resource base that supports human life like comfortable heat management,electricity production,and water supply.The basic principles of thermal photonic management,the regulation of SSA materials,and functional properties are summarized.An outlook discussing challenges and opportunities in SSA material energy management for comfortable living environments is finally presented,which expects the enormous potential of this interdisciplinary research in solving growing resource-shortage of human society.

Chiral liquid crystal elastomers advance light modulation

Chiral liquid crystal elastomers,as soft photonic materials,enable dynamic omnidirectional tuning of circularly polarized reflection wavelength and function as an effective medium for full-color circularly polarized luminescence,showing promise for advanced photonic applications.

Enriched electrophilic oxygen species facilitate acidic oxygen evolution on Ru-Mo binary oxide catalysts

The polymer electrolyte membrane(PEM)electrolyzers are burdened with costly iridium(Ir)-based catalysts and high operation overpotentials for the oxygen evolution reaction(OER).The development of earth-abundant,highly active,and durable electrocatalysts to replace Ir is a critical step in reducing the cost of green hydrogen production.Here we develop a Ru5Mo4Ox binary oxide catalyst that exhibits high activity and stability in acidic OER.The electron-withdrawing property of Mo enriches the electrophilic surface oxygen species,which promotes acidic OER to proceed via the adsorbate evolution pathway.As a result,we achieve a 189 mV overpotential at 10 mA·cm^(-2) and a Tafel slope of 48.8 mV·dec^(-1).Our catalyst demonstrates a substantial 18-fold increase in intrinsic activity,as evaluated by turnover frequency,compared to commercially available RuO_(2) and IrO_(2) catalysts.Moreover,we report a stable OER operation at 10 mA·cm^(-2) for 100 h with a low degradation rate of 2.05 mV·h^(-1).

Liquid Metal-Based Epidermal Flexible Sensor for Wireless Breath Monitoring and Diagnosis Enabled by Highly Sensitive SnS2 Nanosheets

Real-time wireless respiratory monitoring and biomarker analysis provide an attractive vision for noninvasive telemedicine such as the timely prevention of respiratory arrest or for early diagnoses of chronic diseases.Lightweight,wearable respiratory sensors are in high demand as they meet the requirement of portability in digital healthcare management.Meanwhile,high-performance sensing material plays a crucial role for the precise sensing of specific markers in exhaled air,which represents a complex and rather humid environment.Here,we present a liquid metal-based flexible electrode coupled with SnS_(2)nanomaterials as a wearable gas-sensing device,with added Bluetooth capabilities for remote respiratory monitoring and diagnoses.The flexible epidermal device exhibits superior skin compatibility and high responsiveness(1092%/ppm),ultralow detection limits(1.32 ppb),and a good selectivity of NO gas at ppb-level concentrations.Taking advantage of the fast recovery kinetics of SnS_(2)responding to H_(2)O molecules,it is possible to accurately distinguish between different respiratory patterns based on the amount of water vapor in the exhaled air.Furthermore,based on the different redox types of H_(2)O and NO molecules,the electric signal is reversed once the exhaled NO concentration exceeds a certain threshold that may indicate the onset of conditions like asthma,thus providing an early warning system for potential lung diseases.Finally,by integrating the wearable device into a wireless cloud-based multichannel interface,we provide a proof-of-concept that our device could be used for the simultaneous remote monitoring of several patients with respiratory diseases,a crucial field in future digital healthcare management.

Large-area flexible and transparent UV photodetector based on cross-linked Ag NW@ZnO NRs with high performance

A series of large-area,flexible and transparent ultraviolet(UV)photodetectors(PDs)based on Ag nanowire(NW)@ZnO nanorods(NRs)are fabricated by an inexpensive,facile and effective approach.These Ag NW@ZnO NRs are successfully synthesized using a two-step method in an oil bath with a high surface-to-volume ratio and good crystallinity.The PDs are fabricated by drop-coating with different drop-coating times on the surface of polyethylene terephthalate(PET)coupled with Au electrodes.By optimizing the cross-linked network of Ag NW@ZnO NRs,PD2 with a size greater than 25 mm exhibits excellent photoresponse under UV light illumination of 365 nm(1.3 m W cm^(-2))with a bias of 5 V:a high sensitivity of over 10^(3),and a much shorter rise/decay time of 2.6 s/2.3 s.Simultaneously,the detector exhibits an average transmittance of more than 70%in the visible light region,as well as good flexibility and excellent mechanical stability under a bending angle of 120°over 1000 circles bending.These integral advantages have significant potential for practical applications and mass production.

Flexible sensors based on assembled carbon nanotubes

Flexible sensors have attracted significant attention as they could be directly attached to/implanted into the body or incorporated into textiles to monitor human activities and give feedbacks for healthcare.A typical fabrication method is the direct use of intrinsically flexible active materials such as carbon nanotubes(CNTs).CNTs are generally assembled into aligned structures to extend their remarkable chemical,mechanical,and electrical properties to macroscopic scale to afford high sensing performances.In this review,we present the recent advance of CNT assemblies as electrodes or functional materials for flexible sensors.The realizations of aligned CNTs are firstly investigated.A variety of flexible sensors based on the aligned CNTs are then carefully explored,with an emphasis on understanding the working mechanism for their high sensing properties.The main attention is later paid to comparing two main categories of flexible sensors with fiber and film shapes.The remaining challenges are finally highlighted to offer some insights for future study.