Growing demand for wearable electronics has increased interest in devices that combine mechanical compliance with local information processing. Amorphous indium gallium zinc oxide (a-IGZO) is an attractive material because spatially extended metal-cation s-orbital overlap enables relatively high mobility in amorphous films, and the compatibility with low-temperature deposition supports large-area processing. This review examines recent advances in flexible a-IGZO synaptic transistors. It discusses electron transport and ionic–electronic coupling mechanisms in relation to synaptic plasticity and summarizes relevant electrical and mechanical performance metrics. It then evaluates atomic- and molecular-level engineering of channels, dielectrics, and heterointerfaces, together with gate-stack, one-dimensional, vertical, and multigate architectures. Demonstrations of in-sensor, near-sensor, reservoir, and in-memory computing are assessed across individual devices, arrays, and device-based simulations. Finally, we discuss challenges in film uniformity, reproducible weight storage, mechanically reliable array integration, and hardware–software co-design. Addressing these issues is necessary for moving flexible a-IGZO synaptic devices beyond proof-of-concept demonstrations toward reliable computing systems.
Conductive hydrogels can convert external stimuli (such as strain and pressure) into detectable electrical signals, making them ideal candidates for next-generation sensors. Among them, dual-network (DN) hydrogel sensors display uniform stress dissipation, thus effectively enhancing the overall mechanical properties compared to single-network hydrogels. However, the construction of dual networks still faces challenges in reconciling the formation of physically and chemically crosslinked networks. Additionally, the presence of a large amount of unstable “free water” within hydrogels also limits their adaptability to multi-environment sensing. To address these issues, this study developed a stepwise hydrogen bond modulation strategy based on the Hofmeister effect for fabricating DN hydrogels. By introducing magnesium chloride (MgCl2) to weaken interchain hydrogen bonds, polyvinyl alcohol (PVA) hydrogels could achieve more efficient absorption of acrylamide (AAm) solution to form a highly interpenetrating DN. Meanwhile, MgCl2 and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) could synergistically enhance the ionic conductivity. Subsequently, the water/glycerol solution of sodium citrate (Na3Ct) could further strengthen the PVA cross-linking and modulate “free water”, thereby enhancing the mechanical strength and environmental tolerance. The study also provided an in-depth analysis of the underlying mechanism using Raman spectroscopy, offering new insights and theoretical support for related future research. The prepared hydrogel enhanced-PVA/PAAm/PEDOT:PSS/MgCl2 (PPPM-E) demonstrated capabilities in underwater Morse code communication and low-temperature gesture recognition sensing. Based on a convolutional neural network, the system achieved 99.56% accuracy in gesture recognition, highlighting its excellent multi-environment sensing performance.
With the rapid development of high-frequency electronic devices toward greater integration and power density, electronic packaging materials that simultaneously offer high thermal conductivity and low dielectric loss are urgently needed. However, constructing an effective thermal conduction network typically requires high filler loadings, which in turn increase interfacial thermal resistance and raise dielectric loss. To address this challenge, a strategy is proposed that utilizes the liquid crystal orientation behavior of thermotropic liquid crystal polyarylate (LCP) to control the ordered arrangement of functionalized boron nitride (BN-G). During melt processing, highly oriented LCP molecular chains form in-situ microfibrillar structures along the shear flow direction, which align BN-G and facilitate continuous thermal conduction pathways at low filler loadings. These results demonstrate that BN-G is uniformly distributed in an ordered fashion along the in-plane direction within the LCP matrix. The LCP-BN-G composite with 20 wt% filler loading achieved an in-plane thermal conductivity of 1.45 W·m-1·K-1, representing a 196.5% increase over pure LCP, while maintaining a low dielectric constant of 3.36 and dissipation factor of 0.014 at 1 MHz. In summary, a feasible approach is provided herein for designing high-performance thermally conductive composites tailored for high-frequency and low-loss applications.
Soft hydrogels have emerged as key enabling materials for flexible bio-integrated devices owing to their tissue-like softness, high water content, and intrinsic biocompatibility. However, conventional hydrogels suffer from mechanical fragility, limited fatigue resistance, and poor environmental stability, which severely restrict their long-term performance under dynamic physiological conditions. Addressing this challenge has driven the development of combining compliant mechanics with high toughness, durability, and damage tolerance. This review provides a comprehensive overview of recent advances in robust soft hydrogels for flexible bio-integrated devices, with an emphasis on mechanics-guided design and manufacturing strategies. We first discussed molecular and network-level design principles, including chain architecture, dynamic crosslinking, double network structures, and sacrificial energy dissipation, that underpin enhanced toughness and fatigue resistance. We then examine mesoscale and microstructural engineering approaches, such as gradient architectures, anisotropic networks, and nanocomposite reinforcement, that enable mechanical programmability and environmental robustness. Fabrication and scalability strategies, including printing, patterning, and interface engineering, are subsequently reviewed to highlight pathways toward system-level integration. Finally, emerging applications in flexible electronics, electronic skin, soft robotics, and intelligent health monitoring are discussed, together with remaining challenges and future directions for translating robust soft hydrogels into reliable and manufacturable bio-integrated systems.
Slender rod-climbing robots require end-effectors that are lightweight, capable of supporting large axial loads, and able to switch reliably between attachment and detachment during cyclic locomotion. However, existing soft coiling actuators struggle to balance three-dimensional (3D) winding capability, load-bearing performance, structural lightweighting, and controllable release. Herein, we present a fabric-based adhesive winding actuator (FAWA) inspired by biological adhesion–coiling mechanisms. The actuator integrates a wrinkle-guided pleated chamber, constraining-layer bladder, and biomimetic dry adhesive interface within a lightweight fabric pneumatic architecture. This coupled design enables 3D helical winding around rod-like objects while simultaneously supporting adhesive load transfer and release regulation. Experimental results showed that the actuator weighs approximately 2 g and can sustain axial loads exceeding 1,000 times its own weight (> 2 kg) at 50 kPa. It achieved effective adhesive winding on rods over a practical diameter range, with the best performance observed at diameters of 10-12 mm. When integrated into a 430 g rod-climbing robot, the actuator enabled stable climbing on inclined slender rods without external tethered support. These results demonstrate a lightweight robot-oriented actuator design that addresses the coupled requirements of winding generation, load-bearing attachment, and controllable release for slender rod-climbing applications.
Piezochromic metal-organic frameworks (MOFs) hold strong promise for interfacial pressure mapping owing to their structurally tunable sensitivity and sensing range. However, their practical deployment is hindered by structural instability during coating formation and under moisture exposure, as well as by the difficulty of obtaining color-uniform thin films. Herein, we report a solvent-exchange and encapsulation strategy that stabilizes MOF structures by weakening solvent-framework interactions and blocking moisture ingress, enabling highly stable piezochromic MOF films. Concurrently, highly color-uniform MOF films are realized through interfacial wettability regulation, enabling the identification of the surface roughness of 1000-grit sandpaper via pressure mapping. Moreover, the MOF coating process is adaptable to curved surfaces, allowing the recording of collision pressure distributions that are difficult to capture using electronic devices. This work demonstrates the great potential of piezochromic MOFs in film and coating formats for high-resolution interfacial pressure mapping.
Organ function relies on dynamic electrical and electrochemical signaling that governs processes ranging from cardiac conduction and neural activity to gastrointestinal (GI) regulation and endocrine communication. Bioelectronic devices have demonstrated clinical impact in applications such as cardiac pacing, cochlear implants, retinal prostheses, and continuous glucose monitoring. However, when deployed on soft, wet, and continuously moving organs, the long-term stability of the device–tissue interface becomes a key challenge due to mechanical mismatch, biofouling, and degradation in physiological environments. Increasing evidence suggests that universal device architectures are insufficient for reliable long-term operation across organs with distinct mechanical, biochemical, and immunological microenvironments. Organ-specific bioelectronics has therefore emerged as a design paradigm in which materials, device structures, and system architectures are co-optimized according to the deformation modes, chemical conditions, and biological responses of individual tissues. Recent advances include ultracompliant neural interfaces that minimize inflammatory responses, GI resident devices capable of operating under strong peristalsis and chemical exposure, stretchable epidermal electronics that seamlessly integrate with skin mechanics, and epicardial or renal surface patches for monitoring visceral organs. This review summarizes recent developments in organ-specific bioelectronics from integrated perspectives of materials, device structures, and biological systems. Key material platforms, fabrication strategies, and representative applications are highlighted, followed by discussion of challenges in long-term biostability, scalable manufacturing, wireless power and data communication, and clinical translation, as well as future opportunities for organ-mimetic electronic interfaces enabling continuous monitoring and therapeutic modulation.
Blockages in cerebral arteries restrict blood flow to the brain, leading to several life-threatening conditions such as stroke. The standard treatment, known as catheter-assisted balloon angioplasty, involves threading a mechanical guidewire and catheter-mounted balloon to the blockage, where the balloon is inflated to reopen the blocked artery. However, this approach struggles with the limited navigation capability of pre-shaped guidewires and catheters, especially in tortuous and small arteries with diameters <= 2 mm. Emerging miniature robots offer a potential alternative for catheter-free angioplasty via wirelessly actuated expansion. Still, they typically require high-power electromagnetic coils and short actuation distances, limiting their practicality for small-vessel interventions. In this work, we introduce a magnetic balloon fiberbot (MBF) that synthesizes advanced materials, electromagnetic resonance strategies, and minimally invasive magnetic actuation. The MBF incorporates a magnetically deflectable tip for navigating complex vasculature, along with a phase-change balloon integrated into a nitinol-cored polydimethylsiloxane fiber. Under low-power microwave heating (50 W at 15 cm), the balloon expands safely within 42-50 degrees C. This efficient heating stems from a carbon-nanotube coating that absorbs energy effectively, combined with the electromagnetic resonance of the optimized nitinol core. The nitinol core thus acts as both a structural backbone and a microwave-coupling element. We validate MBF performance in vitro using a 3D cerebrovascular phantom and ex vivo in porcine placenta models. With reduced power demands, long-range actuation, and favorable biocompatibility, the MBF represents a promising catheter-free strategy for minimally invasive treatment of blockages in small arteries.
The rapid evolution of smart textiles has created a pressing demand for soft conductive fibers that simultaneously possess outstanding mechanical flexibility and high electrical conductivity. Emerging two-dimensional materials, particularly graphene and transition metal carbides/nitrides (MXenes), serve as ideal building blocks for constructing such high-performance soft conductive fibers. This review systematically summarizes recent advances in soft conductive fibers based on graphene and MXene nanosheets, with a primary focus on their integration into smart textiles. This review focus on the mainstream fabrication techniques including wet spinning, surface coating, and electrospinning which translate the intrinsic microscopic properties of graphene and MXene nanosheets into practical macroscopic fibrous assemblies. These soft conductive fibers can be effectively woven into smart textiles for a variety of wearable applications, such as electromagnetic shielding, flexible sensing, personal healthcare, thermal management and energy harvesting/storage. Furthermore, the review also discusses graphene/MXene composite and hybrid fibers, highlighting their fabrication strategies, synergistic reinforcement mechanisms, and enhanced performance benefits. Finally, we present a critical perspective on the opportunities and challenges facing graphene and MXene fibers in the pursuit of practical, large-scale wearable applications. Owing to their unique combination of properties, graphene and MXene fibers establish a robust platform for advanced wearable electronics and pave the way for next-generation smart textiles.
Aging populations face growing multimorbidity, while episodic clinical assessments fail to capture gradual physiological changes unfolding during daily life. Although wearable technologies enable continuous monitoring, single-modality systems provide incomplete and context-limited insight. This Perspective focuses on hybrid wearable sensors that integrate physical and chemical sensing for geriatric healthcare. Hybrid wearable sensing provides a pathway toward continuous, predictive, and personalized geriatric health management. By monitoring continuously multiple health parameters, such multimodal systems have distinct advantages for real-time monitoring, including early risk detection and more personalized health assessment through the integration of complementary physical and biochemical signals. We discuss recent advances in wearable physical sensors, alongside with emerging wearable chemical sensors, then argue that chem-phys hybrid integration enables more interpretable and clinically actionable assessment of aging trajectories than single-modality wearable systems. Finally, we discuss translational requirements and future prospects, including robust real-world operation, AI-driven inference, and integration with telemedicine and home-based care.
Flexible tactile sensors serve as the essential sensory interfaces for compliant physical interaction in advanced intelligent systems, such as embodied intelligence robotics and smart wearable devices. To meet the increasing demand for rich and precise tactile information, achieving high-resolution perception has become a vital performance metric for these flexible tactile sensing systems. This review presents a systematic overview of flexible tactile sensors from the perspective of high-resolution realization mechanisms, mainly encompassing two paradigms: array-based spatial information sampling via discrete taxel layouts, and array-free spatial information inference over continuous tactile sensing medium. First, dense taxel layouts are introduced as conventional array-based strategies for high-resolution realization. Then, the emerging sparse layout strategies enabled by artificial intelligence (AI) algorithms are described, achieving super-resolution sensing beyond physical layout density. Subsequently, we summarize the array-free strategies for high-resolution tactile sensing over continuous sensing medium, focusing on physics-based inference and learning-based prediction. In addition, we show typical examples of their applications in enhanced interaction scenarios. Finally, future trends toward scalable, generalizable, multimodal, and highly integrated flexible tactile sensing systems are discussed, with scientific challenges and potential development pathways outlined.
Flexible tactile sensors capable of resolving complex mechanical stimuli are essential for advanced electronic skins. However, simultaneous perception of force magnitude, direction, and dynamic loading remains challenging without complex circuitry. Here, we report a kirigami-enabled, skin-inspired flexible sensor that achieves spatially distributed receptor-like responses through a three-dimensional (3D) laser-induced graphene (LIG) network. By transferring LIG from a kirigami-engineered polyimide substrate, we transform a planar conductive layer into a 3D architecture with height-dependent electrical characteristics. This structural differentiation enables spatially-encoded electromechanical transduction, where heterogeneous sensitivities across the 3D-LIG network translate simple stimuli into high-dimensional signal features. Consequently, the architecture inherently decouples force amplitude from dynamic loading through its non-linear deformation profiles. By further leveraging kirigami-induced anisotropy, the sensor achieves simultaneous resolution of multidirectional force vectors without requiring complex peripheral circuitry. The sensor demonstrates a linear pressure range of 0-35 kPa and high durability over 10,000 cycles. Leveraging this “structural coding” paradigm, the device enables high-accuracy recognition of surface roughness (95.34%) and gait patterns (91.77%) via machine learning. This work offers a robust strategy for biomimetic tactile sensing by integrating 3D structural engineering with intrinsic multidimensional signal decoupling. This design provides a promising foundation for intelligent prosthetics and human machine interfaces, achieving force vector resolution within a single structure.
Wheeled robotic platforms are widely favored for their high mobility, cost-effectiveness, and long operational endurance. However, their traversal performance substantially deteriorates on uneven or obstructed terrain due to the intrinsic limitations of rigid wheels, which lack adaptability to varying surface topologies. To overcome these constraints, we present a reconfigurable, nonpneumatic spiral wheel featuring tunable radial stiffness. The wheel switches between two functional configurations: a contracted, high-stiffness mode for high-speed locomotion on flat surfaces; and an expanded, low-stiffness mode that increases compliance and traction for obstacle negotiation. The design is implemented using a monolithic, 3D-printed chiral structure actuated via a rope-driven mechanism. The system is then subjected to a series of indoor and outdoor locomotion tests upon integration with a wheel-legged robotic platform. The experimental results confirm that the proposed wheel maintains dynamic stability and speed efficiency on planar surfaces while substantially enhancing terrain adaptability and obstacle-crossing performance in complex environments.
Muscle fatigue and injury are the core issues that restrict the improvement of athletes’ competitive performance and the maintenance of sports health for the general population. The traditional muscle health management paradigm is limited by lagging assessment and single indicators, failing to meet the demands of precise training and individualized rehabilitation. With the advances in wearable sensing technology, muscle health management has the potential to transform from the empirical modality to a new data-driven paradigm. However, existing publications either focus on materials innovation and structure design in sensor development, or solely highlight the overlapping physiological mechanisms inducing muscle fatigue and injury. Thus, a comprehensive review presenting insights on the physiological relevance between biological signals fluctuations and muscle health status, the detection mechanisms and functional layouts of wearable sensors to capture these signals, as well as their real-world applications in competitive sports and public fitness is timely needed. Herein, this article systematically reviews the physiological mechanisms of muscle fatigue, injury and repair, with a focus on elaborating the characteristic change patterns of related bioelectrical, biochemical and biomechanical markers in the process. Sensing mechanisms and working layouts of wearable technology are comprehensively summarized. Importantly, corresponding applications in real-world settings associated with improving professional athletic performance and public fitness are proposed, including load monitoring, fatigue evaluation, personalized nutrition management, as well as artificial intelligence (AI)-enabled multimodal fusion. Based on this, future perspectives are envisioned to better aid sports activities and engineer the development of sports science and sports medicine.
Biodegradable bioelectronic systems require materials that can mechanically integrate with soft tissues while minimizing long-term invasiveness. Conventional electronic materials, owing to their high stiffness, often cause mechanical mismatch with biological tissues, leading to chronic inflammation and tissue damage. To address these challenges, biodegradable conductive materials based on organic and polymeric systems have emerged as promising candidates for transient, biofriendly electronics. This review provides a comprehensive overview of recent advances in biodegradable conductive systems, including conductive polymers, conductive composite pastes, and organic mixed ionic-electronic conductors (OMIECs). The discussion covers material design strategies that simultaneously address electrical performance, mechanical compliance, and degradability in both partially and fully degradable systems. Particular attention is given to the relationships among degradation behavior, microstructure, and device stability, which play critical roles in determining functional lifetime. The scope further extends to key bioelectronic applications, including bioelectrical stimulation, drug delivery, sensing, and neuromorphic systems, demonstrating the versatility of these materials across diverse platforms. Emphasis is placed on providing an integrated perspective for the design of next-generation transient bioelectronic systems based on biodegradable organic conductors.
Traditional rigid underwater vehicles are often bulky and exhibit poor maneuverability, which limits their deployment in complex marine environments. In contrast, bio-inspired soft robotic fish are capable of mimicking efficient aquatic propulsion, while maintaining a compact structure and enhancing interaction safety. They demonstrate significant potential for marine sensing and exploration. Despite these advantages, reliable underwater locomotion control for dielectric elastomer actuators (DEAs) driven systems remains highly challenging because of large nonlinear deformations, time-varying parameters, and strong hydrodynamic damping. As a result, most existing prototypes still operate primarily in open loop. In this study, we develop a centimeter-scale manta ray-inspired robotic fish actuated by underwater-compatible rolled-type DEAs. Systematic underwater experiments are conducted, including speed regulation and turning performance tests. To attain stable and reliable underwater control, an experimentally calibrated voltage-curvature relationship for the rolled-type DEAs is established, and an underwater input-output model for reciprocating actuation is identified. These two factors jointly facilitate the implementation of a fuzzy proportional-integral-derivative (PID) closed-loop controller. Compared with open-loop operation, the closed-loop system improves disturbance rejection and dynamic response, resulting in more consistent swimming performance and maneuvering control. These results offer a practical approach for integrating the fabrication of DEAs, underwater integration, and closed-loop control, and contribute to the advancement of highly maneuverable centimeter-scale soft underwater robots.
The growing accumulation of electronic waste (e-waste) and demand for environmentally sustainable technologies have accelerated interest in transient degradable electronics, which physically disintegrate or biodegrade after their functional lifetime. Such devices offer promising pathways towards reducing ecological impact while enabling applications in biomedical implants, environmental sensors, and temporary wearable systems. Biodegradable organic thin-film transistors (OTFTs) play a pivotal role as fundamental building blocks for fully transient electronic circuits, combining mechanical flexibility, solution processability, and controlled disintegration. In this study, we report the development of a fully degradable OTFT fabricated using diketopyrrolopyrrole thiophene-imine-thiophene as the biodegradable semiconducting layer, integrated with a bilayer dielectric composed of poly(vinyl alcohol) (PVA) and poly(caprolactone) (PCL), and a poly(lactic acid) (PLA) substrate. This configuration yields a significant reduction in threshold voltage (VT) from -16.1 to -2 V compared to devices fabricated on octyltrichlorosilane/SiO2, while maintaining comparable charge carrier mobility. The OTFT can be selectively degraded through sequential steps, where the semiconductor dissolves under acidic conditions (1 M HCl), followed by degradation of the dielectric and substrate in basic buffer solution. This controlled disassembly enables separation and potential recycling of individual components, providing a straightforward strategy for environmentally responsible end-of-life management of transient electronics. Overall, this work represents an important step toward realizing low-voltage, fully degradable, and recyclable electronic systems for sustainable applications.
