Soft fluidic devices are important for wearable applications involving mass and heat transfer. Based on charge injection electrohydrodynamics, a fluidic fiber pump made of polyurethane and copper wires has been reported to show outstanding performances in terms of pressure, flow rate and power density. Its flexible fiber shape allows integration compatible with textiles, opening new possibilities in the ever-growing field of wearable technology.

The integration of a display function with wearable interactive sensors offers a promising way to synchronously detect physiological signals and visualize pressure/stimuli. However, combining these two functions in a strain sensor textile is a longstanding challenge due to the physical separation of sensors and display units. Here, a water-stable luminescent perovskite hydrogel (emission band approximately 25 nm) is constructed by blending as-prepared CsPbBr3@PbBr(OH) with stretchable polyacrylamide (PAM) hydrogels. The facile introduction of CsPbBr3@PbBr(OH) endows the hydrogels with excellent optical properties and a high mechanical strength of 51.3 kPa at a fracture strain of 740%. Interestingly, the resulting hydrogels retain bright green fluorescence under conditions including water, ultraviolet light, and extensive stretching (> 700%). As a proof-of-concept, a novel wearable stretchable strain sensor textile based on these hydrogels is developed, and it displays visual-digital synergetic strain detection ability. It can perceive various motions on the human body in real time with electronic output signals from changes in resistance and simultaneously readable optical output signals, whether on land or underwater. This work provides a meaningful guide to rationally design perovskite hydrogels and accelerates the development of wearable visual-digital strain sensor textiles.Graphical Abstract

For the optimal functional recovery of force-transmitting connective tissues, obtaining grafts that are mechanically robust and integrating them with host bone effectively to tolerate high loads during violent joint motions is both crucial and challenging. Recent research proposes that a hierarchical helical carbon nanotube fiber, which has the considerably high mechanical strength, and can integrate with the host bone and restore movement in animals, is a very promising artificial ligament. The above research marks a significant development in artificial ligament via the innovative utilization of hierarchical helical carbon nanotube fiber.

High-performance yarn artificial muscles are highly desirable as miniature actuators, sensors, energy harvesters, and soft robotics. However, achieving a yarn artificial muscle that covers all the properties of excellent actuation performance, mechanical robustness, structural stability, and high scalability by a low-cost strategy is still a great challenge. Herein, a bio-inspired fasciated yarn structure is first reported for creating robust high-performance yarn artificial muscles. Unlike conventional strategies that leverage costly materials or complex processing, the developed yarn artificial muscles are constructed by hierarchically helical and sheath-core assembly design of cost-effective common fibers, such as viscose and polyester. The hierarchically helical sheath structure pushes the theoretical limit of the inserted twist in yarns and endows the yarn muscles with large stroke (5815° cm−1) and high work capacity (23.5 J kg−1). Due to the rapid water transfer and efficient energy conversion of inter-sheath–core coupling, the as-prepared yarn muscles possess fast response, high rotation accelerated speed, and low recovery hysteresis. Moreover, the inactive core yarn serves as support for internal tethering and load-bearing, enabling these yarn muscles to maintain a self-stable structure, robust life cycle and mechanics. We show that the yarn muscle fabricated in this method is readily available and highly scalable for achieving high-dimensional actuation deformations, which considerably broadens the application scenarios of artificial muscles. Graphic abstractThe hierarchically helical and sheath-core structures are embraced to create high-performance artificial muscles with a large stroke, a fast response, a high work capacity, a self-supporting morphology and robust mechanical properties at a low-cost strategy, which boosts the scalable production and practical applications of artificial muscles and is expected to provide new opportunities in the development of miniature actuators, smart textiles and soft robotics.

Achieving efficient hemostasis and wound management is vital to preserve life and restore health in case of extensive hemorrhagic skin damage. Here, we develop a filter pump-like hierarchical porous-structure (HPS) dressing based on a non-woven substrate, konjac glucomannan (KGM) aerogel, and bi-functional microporous starch (BMS). The KGM aerogel intercalates into the non-woven network structure, forming a hydrophilic frame to stimulate the plasma permeation toward the interior in synergy with the hydrophilic pores of the BMS. The BMS surface forms a hydrophobic matrix that fills the spaces of the KGM hydrophilic frame, contributing to the isolation and aggregation of blood cells on the surface of the HPS dressing to establish rapid hemostasis. Animal model experiments suggest reliable HPS dressing hemostatic capacity, as it is able to stop ear artery and liver bleeding within 97.6 ± 15.2 s and 67.8 ± 5.4 s, respectively. Furthermore, the dressings exhibit antibacterial properties and enabled wound healing within 2 weeks. In vitro hemolysis and cytotoxicity tests also confirm the biocompatibility of HPS dressings. This novel “two-in-one” hemostatic dressing facilitates tissue repair of bleeding wounds over the entire recovery period, thereby providing a convenient strategy for wound management.Graphical AbstractA Gemini HPS dressing for both hemostasis and wound healing was proposed using amphiphilic hierarchical-porous structures to isolate and aggregate blood cells to promote hemostasis, and alloy nanoparticles to inhibit bacterial proliferation to accelerate wound healing.

Intense heat waves pose a serious threat to public health and well-being, especially in outdoor spaces. Outdoor high-temperature environments without air conditioners are major challenges for humanity. However, an achievable approach that can provide outdoor cooling without consuming any energy is lacking. Hence, this work presents a novel hierarchical fabric emitter (HFET) used for sunshade sheds to provide radiative outdoor cooling for humanity, the HFET is composed of polyethylene/silicon dioxide/silicon nitride film, melt-blown polypropylene film, and polydimethylsiloxane film from top to bottom. In addition to reflecting 94% solar irradiance by its top surface, the HFET shows selective emission (0.82 in the atmospheric window and 0.38 outside the atmospheric window) on its top surface to outer space and broadband absorption (0.80 in the longwave infrared band) on its bottom surface from the inside. This bidirectional asymmetric emission enables the simulated skin to avoid overheating by 2–11 °C relative to the reverse HFET and bare cases under direct sunlight. Due to its excellent cooling capability, the HFET will be one of the most considerable solutions for outdoor cooling in hot summer environments.Graphical Abstract

Air pollution containing particulate matter (PM) and volatile organic compounds has caused magnificent burdens on individual health and global economy. Although advances in highly efficient or multifunctional nanofiber filters have been achieved, many existing filters can only deal with one type of air pollutant, such as capturing PM or absorbing and detecting toxic gas. Here, highly efficient, dual-functional, self-assembled electrospun nanofiber (SAEN) filters were developed for simultaneous PM removal and onsite eye-readable formaldehyde sensing fabricated on a commercial fabric mask. With the use of an electrolyte solution containing a formaldehyde-sensitive colorimetric agent as a collector during electrospinning, the one-step fabrication of the dual-functional SAEN filter on commercial masks, such as a fabric mask and a daily disposable mask, was achieved. The electrolyte solution also allowed the uniform deposition of electrospun nanofibers, thereby achieving the high efficiency of PM filtration with an increased quality factor up to twice that of commercial masks. The SAEN filter enabled onsite and eye-readable formaldehyde gas detection by changing its color from yellow to red under a 5 ppm concentrated formaldehyde gas atmosphere. The repetitive fabrication and detachment of the SAEN filter on a fabric mask minimized the waste of the mask while maintaining high filtration efficiency by replenishing the SAEN filters and reusing the fabric mask. Given the dual functionality of SAEN filters, this process could provide new insights into designing and developing high performance and dual-functional electrospun nanofiber filters for various applications, including individual protection and indoor purification applications.Graphical Abstract

Photothermal therapy (PTT) has been proposed as an advanced patient-centered strategy for tumor treatment. Nevertheless, the uncertain safety of conventional photothermal conversion agents and the presence of intracellular self-protective autophagy mechanisms pose obstacles to the clinical application and efficacy of PTT. As we are deeply aware of the seriousness of these problems, we herein proposed an efficacy-enhancing strategy based on an implantable membrane platform (PPG@PB-HCQ) constructed from poly (lactic acid) (PLA), poly (ɛ-caprolactone) (PCL) and gelatin (Gel) electrospun nanofibers (PPG) and loaded with the biodegradable high-efficiency photothermal conversion agent Prussian blue (PB) and the autophagy inhibitor hydroxychloroquine sulfate (HCQ). Cellular experiments confirmed that the PPG@PB-HCQ nanofiber membrane exhibited a significantly stronger tumor cell-killing effect compared with the PTT alone. This enhancement features by of blocking the fusion of autophagosomes with lysosomes. The intracellular overexpression of the proteins microtubule-associated protein 1 light chain 3 (LC3)-II and p62 and the low expression of the proteins LC3-I and Rab7 (members of the RAS oncogene family) further demonstrated autophagic flux blockade. Importantly, the potent antitumor effect of the PPG@PB-HCQ therapeutic platform in B16 tumor-bearing model mice verified the efficacy-enhancing strategy of synergistic PTT and protective autophagy blockade. The present study provides a promising strategy for solving the difficulties of tumor treatment, as well as a new perspective for designing novel treatment platforms.Graphical Abstract

Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors. However, graphene sheets are prone to slips under repeated compression due to inadequate chemical connections. In addition, the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research, making it difficult to perform real-temperature detections. To address these issues, a hyperelastic polyimide fiber/graphene aerogel (PINF/GA) with a three-dimensional interconnected structure was fabricated by simple one-pot compounding and in-situ welding methods. The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers, which can effectively avoid slidings between fibers to form reinforced ribs, preventing graphene from damage during compression. In particular, the inner core of the fiber maintains its macromolecular chain structure and toughness during welding. Thus, PINF/GA has good structural stabilities under a large strain compression (99%). Moreover, the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains, with its thermal-conductivity change ratio reaching up to 9.8. Hyperelastic PINF/GA, with dynamically stable thermal and electrical conductivity, as well as high heat tolerance, shows broad application prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments.Graphical AbstractPolyimide fibers in graphene aerogel are in-suit welded to fabricate a composite with excellent hyperelasticity and adjustable thermal conductivity for artificial intelligence sensing over a wide temperature range.

Natural structural materials, such as spider silk, wood, and bone, are universally acknowledged as the gold standard for the ideal combinations of strength and toughness. The exceptional integrated performance of these biological materials can be ascribed to their multiscale hierarchical architectures and components. Mimicking the hierarchical assembly feature of natural materials, artificial fibers, which are generated through the one-dimensional (1D) assembly of nanowires, have been widely reported with remarkable flexibility and functionality. Furthermore, the distinguishing feature of nanowires’ 1D assembly can bridge the unique properties of nanowires with their potential functional applications. This tutorial review summarizes the recent developments in the assembly of nanowires into macroscopic 1D fibers in the liquid state. We begin by introducing the general strategies and mechanisms for assembling nanowires in one direction and then, illustrate their potential applications in energy storage, sensors, biomedical engineering, etc. Finally, a brief summary and some personal perspectives on the future research directions of nanowires’ 1D assembly are also proposed.Graphical Abstract

Long-term continuous health care monitoring, using wearable technologies has received considerable interest due to the significant contribution of wearables to the diagnosis of diseases and identification of health conditions. Fibers have been widely applied in human societies due to their unique advantages, including stretchability, small diameters, high dynamic bending elasticity, high length-to-width ratios, and mechanical strength. A new generation of fiber-based electrodes is being integrated into smart textiles and wearables for continuous long-term biosignal monitoring. Dry fiber-based electrodes are breathable, flexible, and durable, unlike conventional disposable gel electrodes, which are difficult to employ for long-term applications because of skin irritation and allergic responses caused by their moist and adhesive interface with the skin. In this review, we provide a concise summary of recent breakthroughs in the design, and manufacturing of dry fiber-based electrodes for electrophysiology applications, with a particular emphasis on applications in electrocardiography, electromyography, and electroencephalography. Focusing on numerous features of electroactive fiber materials, fiber processing, electrode fabrication, scaled-up manufacturing, standardization of testing and performance criteria, we discuss current limitations and provide an outlook for the future development of this field.Graphical Abstract

AbstractAir pollution caused by the rapid development of industry has always been a great issue to the environment and human being’s health. However, the efficient and persistent filtration to PM0.3 remains a great challenge. Herein, a self-powered filter with micro–nano composite structure composed of polybutanediol succinate (PBS) nanofiber membrane and polyacrylonitrile (PAN) nanofiber/polystyrene (PS) microfiber hybrid mats was prepared by electrospinning. The balance between pressure drop and filtration efficiency was achieved through the combination of PAN and PS. In addition, an arched TENG structure was created using the PAN nanofiber/PS microfiber composite mat and PBS fiber membrane. Driven by respiration, the two fiber membranes with large difference in electronegativity achieved contact friction charging cycles. The open-circuit voltage of the triboelectric nanogenerator (TENG) can reach to about 8 V, and thus the high filtration efficiency for particles was achieved by the electrostatic capturing. After contact charging, the filtration efficiency of the fiber membrane for PM0.3 can reach more than 98% in harsh environments with a PM2.5 mass concentration of 23,000 µg/m3, and the pressure drop is about 50 Pa, which doesn’t affect people’s normal breathing. Meanwhile, the TENG can realize self-powered supply by continuously contacting and separating the fiber membrane driven by respiration, which can ensure the long-term stability of filtration efficiency. The filter mask can maintain a high filtration efficiency (99.4%) of PM0.3 for 48 consecutive hours in daily environments.Graphical abstract

The lithium-ion (Li-ion) battery has received considerable attention in the field of energy conversion and storage due to its high energy density and eco-friendliness. Significant academic and commercial progress has been made in Li-ion battery technologies. One area of advancement has been the addition of nanofiber materials to Li-ion batteries due to their unique and desirable structural features including large aspect ratios, high surface areas, controllable chemical compositions, and abundant composite forms. In the past few decades, considerable research efforts have been devoted to constructing advanced nanofiber materials possessing conductive networks to facilitate efficient electron transport and large specific surface areas to support catalytically active sites, both for the purpose of boosting electrochemical performance. Herein, we focus on recent advancements of nanofiber materials with carefully designed structures and enhanced electrochemical properties for use in Li-ion batteries. The synthesis, structure, and properties of nanofiber cathodes, anodes, separators, and electrolytes, and their applications in Li-ion batteries are discussed. The research challenges and prospects of nanofiber materials in Li-ion battery applications are delineated.Graphic Abstract

AbstractCarbon fibers (CFs) demonstrate a range of excellent properties including (but not limited to) microscale diameter, high hardness, high strength, light weight, high chemical resistance, and high temperature resistance. Therefore, it is necessary to summarize the application market of CFs. CFs with good physical and chemical properties stand out among many materials. It is believed that highly fibrotic CFs will play a crucial role. This review first introduces the precursors of CFs, such as polyacrylonitrile, bitumen, and lignin. Then this review introduces CFs used in BESs, such as electrode materials and modification strategies of MFC, MEC, MDC, and other cells in a large space. Then, CFs in biosensors including enzyme sensor, DNA sensor, immune sensor and implantable sensor are summarized. Finally, we discuss briefly the challenges and research directions of CFs application in BESs, biosensors and more fields.Highlights CF is a new-generation reinforced fiber with high hardness and strength. Summary precursors from different sources of CFs and their preparation processes. Introduction of the application and modification methods of CFs in BESs and biosensor. Suggest the challenges in the application of CFs in the field of bio-electrochemistry. Propose the prospective research directions for CFs. Graphical abstract

With increasing personalized healthcare, fiber-based wearable temperature sensors that can be incorporated into textiles have attracted more attention in the field of wearable electronics. Here, we present a flexible, well-passivated, polymer–nanocomposite–based fiber temperature sensor fabricated by a thermal drawing process of multiple materials. We engineered a preform to optimize material processability and sensor performance by considering the rheological and functional properties of the preform materials. The fiber temperature sensor consisted of a temperature-sensing core made from a conductive polymer composite of thermoplastic polylactic acid, a conductive carbon filler, reduced graphene oxide, and a highly flexible linear low-density polyethylene passivation layer. Our fiber temperature sensor exhibited adequate sensitivity (− 0.285%/°C) within a temperature range of 25–45 °C with rapid response and recovery times of 11.6 and 14.8 s, respectively. In addition, it demonstrated a consistent and reliable temperature response under repeated mechanical and chemical stresses, which satisfied the requirements for the long-term application of wearable fiber sensors. Furthermore, the fiber temperature sensor sewn onto a daily cloth and hand glove exhibited a highly stable performance in response to body temperature changes and temperature detection by touch. These results indicate the great potential of this sensor for applications in wearable, electronic skin, and other biomedical devices.Graphical Abstract

Carbon-based fibrous supercapacitors (CFSs) have demonstrated great potential as next-generation wearable energy storage devices owing to their credibility, resilience, and high power output. The limited specific surface area and low electrical conductivity of the carbon fiber electrode, however, impede its practical application. To overcome this challenge, this study fabricated a CFS by sequentially coating graphene, carbon nanotube, and activated carbon on the carbon fiber surface (CF/G/CNT/AC). The CF/G/CNT/AC exhibited excellent electrochemical performance with a specific capacitance of 692 mF cm–2 at 70 μA cm–2 and good cycling stability over 4000 cycles. This result is ascribed to the increase of contact area between the active material and the current collector. Moreover, the energy density of the as-prepared CF/G/CNT/AC fibrous supercapacitor reaches 86.6 and 37.7 μW cm–2 at power densities of 126 and 720 μW cm–2, respectively, demonstrating its potential for practical applications. In addition, the CF/G/CNT/AC demonstrated favorable traits such as mechanical flexibility, feasibility, and energy storage capacity, qualifying it as a viable alternative for wearable electronic textiles.Graphical abstract

Prevention of spreading viral respiratory disease, especially in case of a pandemic such as coronavirus disease of 2019 (COVID-19), has been proved impossible without considering obligatory face mask-wearing protocols for both healthy and contaminated populations. The widespread application of face masks for long hours and almost everywhere increases the risks of bacterial growth in the warm and humid environment inside the mask. On the other hand, in the absence of antiviral agents on the surface of the mask, the virus may have a chance to stay alive and be carried to different places or even put the wearers at risk of contamination when touching or disposing the masks. In this article, the antiviral activity and mechanism of action of some of the potent metal and metal oxide nanoparticles in the role of promising virucidal agents have been reviewed, and incorporation of them in an electrospun nanofibrous structure has been considered an applicable method for the fabrication of innovative respiratory protecting materials with upgraded safety levels.Graphical Abstract

As mechanical devices for moving or controlling mechanisms or systems, actuators have attracted increasing attention in various fields. Compared to traditional actuators with rigid structures, soft actuators made up of stimulus-responsive soft materials are more adaptable to complex working conditions due to soft bodies and diverse control styles. Different from plate-shaped soft actuators, which have the limited deformations between two dimensional (2D) and 3D-configurations such as bending and twisting, fiber-shaped soft actuators (FSAs) own intriguing deformation modes to satisfy diverse practical applications. In this mini review, the recent progress on the controlled fabrication of the FSAs is presented. The advantages and disadvantages of each fabrication method are also demonstrated. Subsequently, the as-developed actuation mechanisms of the FSAs are displayed. Additionally, typical examples of the related applications of the FSAs in different fields have been discussed. Finally, an outlook on the development tendency of the FSAs is put forward as well.Graphical AbstractA mini review concerns the recent progress of fiber-shaped soft actuators (FSAs) on the fabrication technology, actuation principle and application. In addition, an outlook on the development tendency of the FSAs is made.

AbstractWith the development and prosperity of Internet of Things (IoT) technology, wearable electronics have brought fresh changes to our lives. The demands for low power consumption and mini-type wearable power systems for wearable electronics are more urgent than ever. Thermoelectric materials can efficiently convert the temperature difference between body and environment into electrical energy without the need for mechanical components, making them one of the ideal candidates for wearable power systems. In recent years, a variety of high-performance thermoelectric materials and processes for the preparation of large-scale single-fiber devices have emerged, driving the application of flexible fiber-based thermoelectric generators. By weaving thermoelectric fibers into a textile that conforms to human skin, it can achieve stable operation for long periods even when the human body is in motion. In this review, the complete process from thermoelectric materials to single-fiber/yarn devices to thermoelectric textiles is introduced comprehensively. Strategies for enhancing thermoelectric performance, processing techniques for fiber devices, and the wide applications of thermoelectric textiles are summarized. In addition, the challenges of ductile thermoelectric materials, system integration, and specifications are discussed, and the relevant developments in this field are prospected.Graphical abstract

High-performance fiber-shaped power sources are anticipated to considerably contribute to the continuous development of smart wearable devices. As one-/two-dimensional (1D/2D) frameworks constructed from graphene sheets, graphene fibers and fabrics inherit the merits of graphene, including its lightweight nature, high electrical conductivity, and exceptional mechanical strength. The as-fabricated graphene fiber/fabric flexible supercapacitor (FSC) is, therefore, regarded as a promising candidate for next-generation wearable energy storage devices owing to its high energy/power density, adequate safety, satisfactory flexibility, and extended cycle life. The gap between practical applications and experimental demonstrations of FSC is drastically reduced as a result of technological advancements. To this end, herein, recent advancements of FSCs in fiber element regulation, fiber/fabric construction, and practical applications are methodically reviewed and a forecast of their growth is presented.Graphical Abstract