Ag NW-Embedded Coaxial Nanofiber-Coated Yarns with High Stretchability and Sensitivity for Wearable Multi-Sensing Textiles.

The emerging intelligent piezoresistive yarn/textile-based sensors are of paramount importance for skin-interface electronics, owing to their unparalleled features including softness, breathability, and easy integration with functional devices. However, employing a facile way to fabricate 1D sensing yarns with mechanical robustness, multi-functional integration, and comfortability is still demanded for satisfying the practical applications. Herein, a facile one-step synchronous conjugated electrospinning and electrospraying technique is innovatively employed to continuously construct an Ag NW-embedded polyurethane (PU) nanofiber sensing yarn (AENSY) with hierarchical architecture. This 1D AENSY with weavability and stretchability can be woven into AENSY textile-based sensors integrated with functions of strain and pressure sensing. In this embedded multi-scale architecture, Ag NWs are evenly embedded and locked in the oriented and twisted PU nanofiber (PUNF) scaffold, forming the hierarchical mechanical sensing layer on the surface of the AENSY with favorable stability. Meanwhile, the presence of the elastic PUNFs enhances porosity, elasticity, and considerable deformation space, which in turn endow the AENSY textile-based sensor with a gauge factor (GF) up to 1010, a pressure sensitivity up to 16.7 N-1, high stretchability up to 160%, and high stability under long-term cycles. In addition, the AENSY textile-based sensor exhibits light weight and the unique advantage of skin-friendliness with the human body, which can be directly and conformally attached to the curved human skin to monitor the various human movements. Furthermore, the weavable AENSYs can be integrated into smart textiles with sensing arrays, which are capable for spatial pressure and strain mapping. Thus, the continuous one-step developing process and the stable embedded-twisted fiber structure provide a promising strategy to develop innovative smart yarns and textiles for personalized healthcare and human-machine interfaces.

Wearable textile triboelectric generator based on nanofiber core-spun yarn coupled with electret effect.

Flexible triboelectric generators present a wide range of prospective applications owing to their small size, light weight, and wearability; in addition, they can convert external mechanical energy into electrical energy to provide an energy supply for wearable electronic products. In this study, a wearable textile triboelectric generator was developed by weaving polyurethane (PU) nanofiber core-spun yarn and Si3N4-electret-doped polyvinylidene fluoride (PVDF) nanofiber core-spun yarn into a double-layer fabric. Within the double-layer fabric, one layer was Si3N4-doped PVDF (denoted as Si3N4@PVDF) nanofiber fabric, and the other was PU nanofiber fabric. When subjected to an external mechanical force, PU nanofiber fabric and Si3N4@PVDF nanofiber fabric came into contact and were able to convert external mechanical energy into electrical energy. The most notable instantaneous electrical performance of this triboelectric nanogenerator was open circuit voltage of 71 V, short-circuit current of 0.7 µA, and output power of 56 µW. Additionally, the wearable textile triboelectric generator exhibited superior washability, stability, and cycle durability. More significantly, it was capable of driving some low-consumption electronic products, including capacitors, LED bulbs, and digital meters, thereby exhibiting a strong potential for flexible self-powered electronic devices and intelligent textiles.

Graphene oxide-silver nanocomposites embedded nanofiber core-spun yarns for durable antibacterial textiles.

Antibacterial textiles, which effectively inhibit bacterial breeding and resist pathogenic diseases, have wide applications in medicine, hygiene, and related fields. However, traditional antibacterial textiles exhibit significant limitations, such as poor antibacterial durability and contamination during preparation. In this work, nanofiber yarn loaded with a high-efficiency antibacterial agent was prepared using electrospinning technology. Polyethyleneimine (PEI) was introduced as a solubilizing material to functionalize graphene oxide (GO) to form GO-PEI composites. A facile microwave heating method was used to synthesize GO-PEI and silver nanoparticles (AgNPs). A multi-needle conjugated electrospinning device was used to blend the nanofibers with the GO-PEI-Ag composite to form a nanofiber core-spun yarn. The antibacterial agent was firmly fixed on the fiber to prevent easy removal. A uniformly oriented yarn structure and internal morphology were observed, and the antibacterial activity of the fabric was measured. The antibacterial rate of the fabric was over 99.99%for both Escherichia coli and Staphylococcus aureus. After ten washes, the antibacterial rate remained above 99.99%. Thus, nanofiber fabric from electrospinning displays high antibacterial activity and excellent durability, thereby providing a feasible methodology for future production of antibacterial textiles.

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.

Characterization of Biofilm Formed by Phenanthrene-Degrading Bacteria on Rice Root Surfaces for Reduction of PAH Contamination in Rice.

One effective method in to reduce the uptake of organic contaminants by plants is the development of a root barrier. In this study, the characterization of biofilm structure and function by phenanthrene-degrading Pseudomonas sp. JM2-gfp on rice root surfaces were carried out. Our results showed that root surfaces from three rice species, namely Liaojing401, Koshihikari, and Zhenzhuhong all present hydrophobicity and a high initial adhesion of strain JM2-gfp. Matured robust biofilm formation occurred at 48 h on the root surfaces. The biofilm exhibited cell dense aggregates and biomass embedded in the extracellular polymeric substance (EPS) matrix. EPS composition results showed that the proteins, carbohydrates, lipids and nucleic acids are produced in the biofilm, while the content varied with rice species. Under the initial concentration of phenanthrene 50 mg·L-1, the residual phenanthrene in plant roots from 'Zhengzhuhong', 'Koshihikari' and 'Liaojing401' with biofilm mediated were significantly decreased by 71.9%, 69.3% and 58.7%, respectively, compared to those without biofilm groups after 10 days of exposure. Thus, the biofilm colonized on roots plays an important role of degradation in order to reduce the level of phenanthrene uptake of plants. Thereby, the present work provides significant new insights into lowering the environmental risks of polycyclic aromatic hydrocarbons (PAHs) in crop products from contaminated agriculture soils.

Electrospun Conductive Nanofiber Yarn for a Wearable Yarn Supercapacitor with High Volumetric Energy Density.

One-dimensional, flexible yarn-shaped supercapacitors for woven cloth have the potential for use in different kinds of wearable devices. Nevertheless, the challenge that supercapacitors face is low energy density. In this paper, we present a low-cost and large-scale manufacturing method to construct a supercapacitor yarn with high power and high energy density. To construct the novel and flexible poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)⁻polyacrylonitrile (PDEOT: PSS-PAN)/Ni cotton (PNF/NiC) capacitor yarn, an electrospinning technique was initially used to wrap the polyacrylonitrile (PAN) nanofibers around the core Ni-coated yarn. The PEDOT: PSS⁻PAN nanofiber composite electrode was created using in situ deposition and H3PO4/PVA was used as a gel electrolyte. This electrode material has a yarn/nanofiber/PEDOT: PSS nanoparticle hierarchical structure, providing a high specific area and enhanced pseudocapacitance. The electrode demonstrated a high volumetric capacitance of 26.88 F·cm-3 (at 0.08 A·cm-3), an energy density of 9.56 mWh·cm-3, and a power density of 830 mW·cm-3. In addition, the PNF/NiC capacitor yarns are lightweight, highly flexible, resistant to bending fatigue, can be connected in series or parallel, and may be suitable for a variety of wearable electronic products.

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.

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.

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.