Core-sheath nanofiber yarn for textile pressure sensor with high pressure sensitivity and spatial tactile acuity.

Highly sensitive wearable textile pressure sensors represent the key components of smart textiles and personalized electronics, with potential applications in biomedical monitoring, electronic skin, and human-machine interfacing. Here, we present a simple and low-cost strategy to fabricate highly sensitive wearable textile pressure sensors for non-invasive human motion and physiological signal monitoring and the detection of dynamic tactile stimuli. The wearable textile sensor was woven using a one-dimensional (1D) weavable core-sheath nanofiber yarn, which was obtained by coating a Ni-coated cotton yarn electrode with carbon nanotube (CNT)-embedded polyurethane (PU) nanofibers using a simple electrospinning technique. In our design, the three-dimensional elastic porous nanofiber structure of the force-sensing layer and hierarchical fiber-bundled structure of the conductive Ni-coated electrode provide the sensor with a relatively large surface area, and a sufficient surface roughness and elasticity. This leads to rapid and sharp increases in the contact area under stimuli with low external pressure. As a result, the textile pressure sensor exhibits the advantages of a high sensitivity (16.52 N-1), wide sensing range (0.003-5 N), and short response time (~0.03 s). Owing to these merits, our textile-based sensor can be directly attached to the skin as usual and conformally fit the shape deformations of the body's complex flexible curved surfaces. This contributes to the reliable real-time monitoring of human movements, ranging from subtle physiological signals to vigorous movements. Moreover, a large-area textile sensing matrix is successfully fabricated for tactile mapping of spatial pressure by being worn on the surface of wrist, highlighting the tremendous potential for applications in smart textiles and wearable electronics.

Heterojunction α-Co(OH)2/α-Ni(OH)2 nanorods arrays on Ni foam with high utilization rate and excellent structure stability for high-performance supercapacitor.

The practical implementation of supercapacitors is hindered by low utilization and poor structural stability of electrode materials. Herein, to surmount these critical challenges, a three-dimensional hierarchical α-Co(OH)2/α-Ni(OH)2 heterojunction nanorods are built in situ on Ni foam through a mild two-step growth reaction. The unique lamellar crystal structure and abundant intercalated anions of α-M(OH)2 (M = Co or Ni) and the ideal electronic conductivity of α-Co(OH)2 construct numerous cross-linked ion and electron transport paths in heterojunction nanorods. The deformation stresses exerted by α-Co(OH)2 and α-Ni(OH)2 on each other guarantee the excellent structural stability of this heterojunction nanorods. Using nickel foam with a three-dimensional network conductive framework as the template ensures the rapidly transfer of electrons between this heterojunction nanorods and current collector. Three-dimensional hierarchical structure of α-Co(OH)2/α-Ni(OH)2 heterojunction nanorods provides a large liquid interface area. These result together in the high utilization rate and excellent structure stability of the α-Co(OH)2/α-Ni(OH)2 heterojunction nanorods. And the capacitance retention rate is up to 93.4% at 1 A g-1 from three-electrode system to two-electrode system. The α-Co(OH)2/α-Ni(OH)2//AC device also present a long cycle life (the capacitance retention rate is 123.6% at 5 A g-1 for 10000 cycles), a high specific capacitance (207.2 F g-1 at 1 A g-1), and high energy density and power density (72.6 Wh kg-1 at 196.4 W kg-1 and 40.9 Wh kg-1 at 3491.8 W kg-1), exhibiting a fascinating potential for supercapacitor in large-scale applications.

Hydrangea-like α-Ni1/3Co2/3(OH)2 Reinforced by Ethyl Carbamate "Rivet" for All-Solid-State Supercapacitors with Outstanding Comprehensive Performance.

Improving the self-conductivity and structural stability of electrode materials is a key strategy to improve the energy density, rate performance, and cycle life of supercapacitors. Controlled intercalation of ethyl carbamate (CH3CH2OCONH2) as the rivet between Ni-Co hydroxide layers can be used to obtain sufficient ion transport channels and robust structural stability of hydrangea-like α-Ni1/3Co2/3(OH)2 (NC). Combining the improved electronic conductivity offered by the coexistence of Ni2+ and Co2+ optimizing itself electronic conductivity and the addition of carbon nanotubes (CNTs) as the electron transport bridge between the active material and the current collector and the large specific surface area (296 m2 g-1) reducing the concentration polarization, the capacitance retention ratio of NC-CNT from 0.2 to 20 A g-1 is up to 93.4% and its specific capacitance is as high as 1228.7 F g-1 at 20 A g-1. The large total hole volume (0.40 cm3 g-1) and wide crystal plane spacing (0.71 nm) provide an adequate space to withstand structure deformation during charge/discharge processes and enhance the structural stability of the NC material. The capacitance fading ratio of NC-CNT is only 4.5% at 10 A g-1 for 10 000 cycles. The aqueous supercapacitor (NC-CNT//AC) and all-solid-state supercapacitor (PVA-NC-CNT//PVA-AC) exhibit high energy density (35.2 W h kg-1 at 100.0 W kg-1 and 35.4 W h kg-1 at 100.7 W kg-1), ultrahigh rate performance (the specific capacitances at 20 A g-1 are 92.8 and 87.2% compared to that at 0.5 A g-1), and long cycling life span (the specific capacitances after 100 000 cycles at 10 A g-1 are 91.5 and 90.8% compared with that of their initial specific capacitances), respectively. Therefore, hydrangea-like NC could be a promising material for advanced next-generation supercapacitors.

α-Ni(OH)2/NiS1.97 heterojunction composites with excellent ion and electron transport properties for advanced supercapacitors.

It is recognized that an effective strategy to promote the industrialization of supercapacitors is to enhance the ion and electronic conductivities of electrode materials. In this work, it is demonstrated that the NO/NS-8 heterojunction material obtained via an epitaxial growth method based on ion exchange can be used as an outstanding electrode material for supercapacitors. The construction of heterojunctions between α-Ni(OH)2 and NiS1.97 allows the components to provide each other with ion or electron transport paths and endows NO/NS-8 with excellent ion and electron transport properties; this leads to a high utilization rate of active materials and an unprecedented high specific capacitance (up to 2375.8 F g-1 at 1 mV s-1 in a three-electrode system). Using the as-prepared NO/NS-8 heterojunction material as an electroactive material, an asymmetric supercapacitor with long cycle life (62.8% capacitance retention after 10 000 cycles at a current density of 5 A g-1) and high energy and power densities (128.4 W h kg-1 at a power density of 402.9 W kg-1 and 63.8 W h kg-1 at 7662.7 W kg-1) is finally demonstrated. This work provides a novel strategy for developing unique heterojunction materials for energy storage.

Bio-inspired nano-engineering of an ultrahigh loading 3D hierarchical Ni@NiCo2S4/Ni3S2 electrode for high energy density supercapacitors.

Energy density has become a critical barrier in supercapacitor engineering and improvement of the electrode-loading is urgently demanded. However, there is conflict between the high loading and good electrochemical properties of supercapacitors. Herein, ultrahigh loading (10.33 mg·cm-2) 3D hierarchical NiCo2S4/Ni3S2 on Ni foam with outstanding performance is obtained via bio-inspired nano-engineering, which contains compact nanowire arrays catching urchin-like micro-particles. Using this high-loading material as a binder-free electrode achieves excellent areal capacitances with 16.90 F·cm-2 at 10.33 mA·cm-2 and 1.17 F·cm-2 at 5.17 mA·cm-2 in a three-electrode system and asymmetric supercapacitor device, respectively. The device also exhibits a high energy density of 4.69 W h m-2 (power density of 10.33 W·m-2) and an outstanding stability of 91.4% after 8000 cycles (20.66 mA·cm-2). Its excellent performance is attributed to the well-designed structure and composition: (i) a large contact area with the electrolyte raises the utilization efficiency of the active material, therefore guaranteeing the high capacitance of the active materials; (ii) the high electronic conductivity network constructed through NiCo2S4 and the short diffusion length boost its rate performance; (iii) the reserved space in the hierarchical structure could hold the volume change and enhance the cycling performance of the electrode in the charge/discharge cycles. Thus, this work not only provides a method for the construction of a high-loading and high-performance electrode for asymmetric supercapacitors, but could also shed light on the design of compact nano-materials for other energy storage systems.

High-Performance Flexible Freestanding Anode with Hierarchical 3D Carbon-Networks/Fe7 S8 /Graphene for Applicable Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) have gained tremendous interest for grid scale energy storage system and power energy batteries. However, the current researches of anode for SIBs still face the critical issues of low areal capacity, limited cycle life, and low initial coulombic efficiency for practical application perspective. To solve this issue, a kind of hierarchical 3D carbon-networks/Fe7 S8 /graphene (CFG) is designed and synthesized as freestanding anode, which is constructed with Fe7 S8 microparticles well-welded on 3D-crosslinked carbon-networks and embedded in highly conductive graphene film, via a facile and scalable synthetic method. The as-prepared freestanding electrode CFG represents high areal capacity (2.12 mAh cm-2 at 0.25 mA cm-2 ) and excellent cycle stability of 5000 cycles (0.0095% capacity decay per cycle). The assembled all-flexible sodium-ion battery delivers remarkable performance (high areal capacity of 1.42 mAh cm-2 at 0.3 mA cm-2 and superior energy density of 144 Wh kg-1 ), which are very close to the requirement of practical application. This work not only enlightens the material design and electrode engineering, but also provides a new kind of freestanding high energy density anode with great potential application prospective for SIBs.

Bi-component synergic effect in lily-like CdS/Cu7S4 QDs for dye degradation.

CdS has attracted extensive attention in the photocatalytic degradation of wastewater due to its relatively narrow bandgap and various microstructures. Previous reports have focused on CdS coupled with other semiconductors to reduce the photocorrosion and improve the photocatalytic performance. Herein, a 3D hierarchical CdS/Cu7S4 nanostructure was synthesized by cation exchange using lily-like CdS as template. The heterojunction material completely inherits the special skeleton of the template material and optimizes the nano-scale morphology, and achieves the transformation from nanometer structure to quantum dots (QDs). The introduction of Cu ions not only tuned the band gap of the composites to promote the utilization of solar photons, more importantly, Fenton-like catalysis was combined into the degradation process. Compared with the experiments of organic dye degradation under different illumination conditions, the degradability of the CdS/Cu7S4 QDs is greatly superior to pure CdS. Therefore, the constructed CdS/Cu7S4 QDs further realized the optimization of degradation performance by the synergic effect of photo-catalysis and Fenton-like catalysis.

Significance of Nanomaterials in Wearables: A Review on Wearable Actuators and Sensors.

Together with the evolution of digital health care, the wearable electronics field has evolved rapidly during the past few years and is expected to be expanded even further within the first few years of the next decade. As the next stage of wearables is predicted to move toward integrated wearables, nanomaterials and nanocomposites are in the spotlight of the search for novel concepts for integration. In addition, the conversion of current devices and attachment-based wearables into integrated technology may involve a significant size reduction while retaining their functional capabilities. Nanomaterial-based wearable sensors have already marked their presence with a significant distinction while nanomaterial-based wearable actuators are still at their embryonic stage. This review looks into the contribution of nanomaterials and nanocomposites to wearable technology with a focus on wearable sensors and actuators.

Electrospun Flexible Cellulose Acetate-Based Separators for Sodium-Ion Batteries with Ultralong Cycle Stability and Excellent Wettability: The Role of Interface Chemical Groups.

Na-ion batteries are one of the best technologies for large-scale applications depending on almost infinite and widespread sodium resources. However, the state-of-the-art separators cannot meet the engineering needs of large-scale sodium-ion batteries to match the intensively investigated electrode materials. Here, a kind of flexible modified cellulose acetate separator (MCA) for sodium-ion batteries was synthesized via the electrospinning process and subsequently optimizing the interface chemical groups by changing acetyl to hydroxyl partly. Upon the rational design, the flexible MCA separator exhibits high chemical stability and excellent wettability (contact angles nearly 0°) in electrolytes (EC/PC, EC/DMC, diglyme, and triglyme). Moreover, the flexible MCA separator shows high onset temperature of degradation (over 250 °C) and excellent thermal stability (no shrinkage at 220 °C). Electrochemical measurements, importantly, show that the Na-ion batteries with flexible MCA separator exhibit ultralong cycle life (93.78%, 10 000 cycles) and high rate capacity (100.1 mAh g-1 at 10 C) in the Na/Na3V2(PO4)3 (NVP) half cell (2.5-4.0 V) and good cycle performance (98.59%, 100 cycles) in the Na/SnS2 half cell (0.01-3 V), respectively. Moreover, the full cell (SnS2/NVP) with flexible MCA separator displays the capacity of 98 mAh g-1 and almost no reduction after 40 cycles at 0.118 A g-1. Thus, this work provides a kind of flexible modified cellulose acetate separator for Na-ion batteries with great potential for practical large-scale applications.

Biomineralized poly (l-lactic-co-glycolic acid)-tussah silk fibroin nanofiber fabric with hierarchical architecture as a scaffold for bone tissue engineering.

In bone tissue engineering, the fabrication of a scaffold with a hierarchical architecture, excellent mechanical properties, and good biocompatibility remains a challenge. Here, a solution of polylactic acid (PLA) and Tussah silk fibroin (TSF) was electrospun into nanofiber yarns and woven into multilayer fabrics. Then, composite scaffolds were obtained by mineralization in simulated body fluid (SBF) using the multilayer fabrics as a template. The structure and related properties of the composite scaffolds were characterized using different techniques. PLA/TSF (mass ratio, 9:1) nanofiber yarns with uniform diameters of 72±9µm were obtained by conjugated electrospinning; the presence of 10wt% TSF accelerated the nucleation and growth of hydroxyapatite on the surface of the composite scaffolds in SBF. Furthermore, the compressive mechanical properties of the PLA/TSF multilayer nanofiber fabrics were improved after mineralization; the compressive modulus and stress of the mineralized composite scaffolds were 32.8 and 3.0 times higher than that of the composite scaffolds without mineralization, respectively. Interestingly, these values were higher than those of scaffolds containing random nanofibers. Biological assay results showed that the mineralization and multilayer fabric structure of the composite nanofiber scaffolds significantly increased cell adhesion and proliferation and enhanced the mesenchymal stem cell differentiation toward osteoblasts. Our results indicated that the mineralized nanofiber scaffolds with multilayer fabrics possessed excellent cytocompatibility and good osteogenic activity, making them versatile biocompatible scaffolds for bone tissue engineering.

Development of high-utilization honeycomb-like α-Ni(OH)2 for asymmetric supercapacitors with excellent capacitance.

The low utilization rate of active materials has been a critical obstacle for the industrialization of ultracapacitors. In this study, a thin layer of cross-structured ultrathin α-Ni(OH)2 nanosheets was successfully grown in situ on the surface of a nickel foam as a high-conductivity framework by a vibratory water bath route under a low temperature (80 °C) and mild conditions. Combining the ultrathin α-Ni(OH)2 nanosheets and ultrashort electron transport, the strategy of a perfect intercalation structure of α-Ni(OH)2 and a thin layer of active material on a continuous conductive framework resulted in a high utilization rate of active material, which further achieved high specific capacitance of 213.55 F g-1 at 1 A g-1 in a two-electrode system and high capacitance retention from three to two electrode system (753.79 F g-1 at 1 A g-1 in the three-electrode system). Meanwhile, the device also achieved high energy density of 74.94 W h kg-1 at power density of 197.4 W kg-1 and still retained 24.87 W h kg-1 at power density of 3642 W kg-1.

In situ sulfuration synthesis of flexible PAN-CuS "flowering branch" heterostructures as recyclable catalysts for dye degradation.

"Flowering branch"-like PAN-CuS hierarchical heterostructures were in situ synthesized through a facile hydrothermal sulfuration growth process on PAN-based fibers prepared by electrospinning. The PAN fibers can serve as a stable flexible support, while CuS flowers assembled from nanosheets can act as reactive materials, showing high performance in the degradation of dyes. Moreover, these heterostructures can be recovered easily without a decrease in their photocatalytic activity, thus showing favorable recycling capability.

Highly sensitive, self-powered and wearable electronic skin based on pressure-sensitive nanofiber woven fabric sensor.

The wearable electronic skin with high sensitivity and self-power has shown increasing prospects for applications such as human health monitoring, robotic skin, and intelligent electronic products. In this work, we introduced and demonstrated a design of highly sensitive, self-powered, and wearable electronic skin based on a pressure-sensitive nanofiber woven fabric sensor fabricated by weaving PVDF electrospun yarns of nanofibers coated with PEDOT. Particularly, the nanofiber woven fabric sensor with multi-leveled hierarchical structure, which significantly induced the change in contact area under ultra-low load, showed combined superiority of high sensitivity (18.376 kPa-1, at ~100 Pa), wide pressure range (0.002-10 kPa), fast response time (15 ms) and better durability (7500 cycles). More importantly, an open-circuit voltage signal of the PPNWF pressure sensor was obtained through applying periodic pressure of 10 kPa, and the output open-circuit voltage exhibited a distinct switching behavior to the applied pressure, indicating the wearable nanofiber woven fabric sensor could be self-powered under an applied pressure. Furthermore, we demonstrated the potential application of this wearable nanofiber woven fabric sensor in electronic skin for health monitoring, human motion detection, and muscle tremor detection.

Urchin-Like Ni1/3Co2/3(CO3)1/2(OH)·0.11H2O for Ultrahigh-Rate Electrochemical Supercapacitors: Structural Evolution from Solid to Hollow.

Portable electronics and electric or hybrid electric vehicles are developing in the trend of fast charge and long electric mileage, which ask us to design a novel electrode with sufficient electronic and ionic transport channels at the same time. Herein, we fabricate a uniform hollow-urchin-like Ni1/3Co2/3(CO3)1/2(OH)·0.11H2O electrode material through an easy self-generated and resacrificial template method. The one-dimensional chain-like crystal structure unit containing the metallic bonding and the intercalated OH- and H2O endow this electrode material with abundant electronic and ionic transport channels. The hollow-urchin-like structure built by nanorods contributes to the large electrode-electrolyte contact area ensuring the supply of ions at high current. CNTs are employed to transport electrons between electrode material and current collector. The as-assembled NC-CNT-2//AC supercapacitor device exhibits a high specific capacitance of 108.3 F g-1 at 20 A g-1, a capacitance retention ratio of 96.2% from 0.2 to 20 A g-1, and long cycle life. Comprehensive investigations unambiguously highlight that the unique hollow-urchin-like Ni1/3Co2/3(CO3)1/2(OH)·0.11H2O electrode material would be the right candidate for advanced next-generation supercapacitors.

A graded graphene oxide-hydroxyapatite/silk fibroin biomimetic scaffold for bone tissue engineering.

To better mimic natural bone, a graphene oxide-hydroxyapatite/silk fibroin (cGO-HA/SF) scaffold was fabricated by biomineralizing carboxylated GO sheets, blending with SF, and freeze-drying. The material has increasing porosity and decreasing density from outside to inside. Analysis of GO mineralization in simulated body fluid indicated that carboxylation and Chitosan may synergistically regulate HA growth along the c-axis of weakly crystalline, rod-like GO-HA particles. Compared with HA/SF gradient composites, a cGO-HA gradient scaffold with cGO:HA mass ratio 1:4 has 5-fold and 2.5-fold higher compressive strength and compressive modulus, respectively. Additionally, the cGO-HA/SF composite stimulated mouse mesenchymal stem cell adhesion and proliferation, alkaline phosphatase secretion, and mineral deposition more strongly than HA/SF and pure HA scaffolds. Hence, the material may prove to be an excellent and versatile scaffold for bone tissue engineering.

A Highly Stretchable Nanofiber-Based Electronic Skin with Pressure-, Strain-, and Flexion-Sensitive Properties for Health and Motion Monitoring.

The development of flexible and stretchable electronic skins that can mimic the complex characteristics of natural skin is of great value for applications in human motion detection, healthcare, speech recognition, and robotics. In this work, we propose an efficient and low-cost fabrication strategy to construct a highly sensitive and stretchable electronic skin that enables the detection of dynamic and static pressure, strain, and flexion based on an elastic graphene oxide (GO)-doped polyurethane (PU) nanofiber membrane with an ultrathin conductive poly(3,4-ethylenedioxythiophene) (PEDOT) coating layer. The three-dimensional porous elastic GO-doped PU@PEDOT composite nanofibrous substrate and the continuous self-assembled conductive pathway in the nanofiber-based electronic skin offer more contact sites, a larger deformation space, and a reversible capacity for pressure and strain sensing, which provide multimodal mechanical sensing capabilities with high sensitivity and a wide sensing range. The nanofiber-based electronic skin sensor demonstrates a high pressure sensitivity (up to 20.6 kPa-1), a broad sensing range (1 Pa to 20 kPa), excellent cycling stability and repeatability (over 10,000 cycles), and a high strain sensitivity over a wide range (up to approximately 550%). We confirmed the applicability of the nanofiber-based electronic skin to pulse monitoring, expression, voice recognition, and the full range of human motion, demonstrating its potential use in wearable human-health monitoring systems.

Biomineralized Poly(l-lactic-co-glycolic acid)/Graphene Oxide/Tussah Silk Fibroin Nanofiber Scaffolds with Multiple Orthogonal Layers Enhance Osteoblastic Differentiation of Mesenchymal Stem Cells.

Bone scaffolds with interconnected pores, good mechanical properties, excellent biocompatibility, and osteoinductivity are challenging to fabricate. In this study, we fabricated and characterized the morphology, hydrophilicity, protein adsorptivity, mechanical properties, and fibrous structure of nanofiber scaffolds with multiple, orthogonal layers of composite materials based on poly(l-lactic-co-glycolic acid) (PLGA), graphene oxide (GO), tussah silk fibroin (TSF), and hydroxyapatite (HA). The data show that incorporation of 1 wt % GO into PLGA/TSF nanofibers significantly decreased the fiber diameter from 321 to 89 nm. On the other hand, incorporation of 10 wt % TSF accelerated the nucleation and growth of HA on composite PLGA/GO scaffolds exposed to simulated body fluid. Furthermore, the compressive modulus and stress of composite scaffolds with GO were 1.7-fold and 0.6-fold higher than those of similar scaffolds without GO. Interestingly, composite scaffolds with multiple orthogonal layers exhibited higher compressive modulus and stress compared to scaffolds with randomly oriented nanofibers. Biological assays indicated that mineralized scaffolds with multiple orthogonal layers significantly enhanced cell adhesion, proliferation, and differentiation of mesenchymal stem cells into osteoblasts. In summary, the data indicate that these scaffolds have excellent cytocompatibility and osteoinductivity and have potential as versatile substrates for bone tissue engineering.

Hierarchical ternary Ni-Co-Se nanowires for high-performance supercapacitor device design.

Large-scale uniform Ni-Co-Se bimetallic ternary nanowires have been successfully synthesized through a successive cation exchange. First, NiSe nanowires in situ grown on nickel foam (NF) were prepared by a facile solvothermal route. Next, a series of ternary materials possessing different proportions of Ni and Co were fabricated by a Co-exchange method using the Ni@NiSe material as a template, which effectively achieved morphological inheritance from the parent material. To explore the electrochemical performance, all synthetic materials were assembled into asymmetric supercapacitor devices. Among asymmetric supercapacitor devices, the Ni@Ni0.8Co0.2Se//active carbon (AC) device exhibited a high specific capacitance of 86 F g-1 at a current density of 1 A g-1 and excellent cycling stability with virtually no decrease in capacitance after 2000 continuous charge-discharge cycles. This device still delivered an energy density of 17 Wh kg-1 even at a high power density of 1526.8 W kg-1. These superior electrochemical properties of Ni@Ni0.8Co0.2Se as an electrode material for supercapacitor devices confirmed the synergistic effect between Co and Ni ions, suggesting their potential application in the field of energy storage.

Consecutive Reaction to Construct Hierarchical Nanocrystalline CuS "Branch" with Tunable Catalysis Properties.

New CuS nanocrystals with a 3D hierarchical branched structure are successfully synthesized through in situ consecutive reaction method with copper foam as template. The formation mechanism of the 3D hierarchical branched structure obtained from the secondary reaction is investigated by adjusting the reaction time. The morphology of CuS nanosheet arrays with the 3D hierarchical branched structure is changed through Cu(2+) exchange. In this method, the copper foam reacted completely, and the as-synthesized CuS@Cu9S5 nanocrystals are firmly grown on the surface of the 3D framework. This tunable morphology significantly influence the physical and chemical properties, particularly catalytic performance, of the materials. The as-obtained material of Cu@CuS-2 with the 3D hierarchical branched structure as catalyst for methylene blue degradation exhibits good catalytic performance than that of the material of Cu@CuS with 2D nanosheets in dark environment. Furthermore, the cation exchange between Cu and Cu(2+) indicates that Cu(2+) in wastewater could be absorbed by Cu@CuS-2 with the 3D hierarchical branched structure. The exchanged resultant of CuS@Cu9S5 retains its capability to degrade organic dyes. This in situ consecutive reaction method may have a significant impact on controlling the crystal growth direction of inorganic material.

A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering.

To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65MPa and tensile strength 180.36MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility.