Abstract Electronic tattoos (e-tattoos) hold great potential for next-generation wearable electronics, but their widespread adoption is limited by challenges in electrical conductivity, mechanical durability, and user comfort. In this study, we introduce an Conductive and Durable EGaIn Particle (CDP) ink designed for imperceptible, untethered, and on-palm skin-integrated e-tattoos to overcome these limitations. By leveraging hydrogen bonding between poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVB-A) with nanosized silver (Ag) particles and oxide shell of EGaIn-based liquid metal particles, CDP achieves an exceptional initial electrical conductivity of 1.35 × 10⁵ S m⁻¹ without post-activation. This formulation facilitates the formation of a stable conductive percolating network while maintaining outstanding mechanical durability and resilience under repeated mechanical stresses, such as rubbing and pinching. These properties arise from the ink’s high conductivity even at a low Ag content and the intrinsic robustness of PVB-A with a high density of hydroxyl groups. To demonstrate its functionality, a CDP-based e-tattoo was applied to a human palm as a pressure-sensitive interconnect for human–machine interfaces. This system wirelessly transmitted real-time pressure data from human fingers to a robotic hand, enabling precise grip control. Our findings highlight the potential of CDP ink for advanced, highly durable e-tattoos in interactive and wearable electronic applications.

Abstract Wireless bioelectronics require alternatives to rigid, bulky batteries for long-term monitoring. This paper reviews resonant inductive coupling (RIC) as an efficient biocompatible power strategy surpassing conventional batteries. We summarize fundamental RIC principles and design parameters for biological environments. We then discuss material and structural strategies for soft, electrically stable coils and their integration into sensing, communication, and closed-loop platforms. Finally, we highlight recent advances in bioresorbable inductive coil systems.

Electrolyte-gated transistors (EGTs) are typically limited to p-type operation, with stable n-type devices remaining scarce. In this study, we demonstrate high-performance n-type EGTs using a poly(benzimidazobenzophenanthroline) (BBL) polymer semiconductor gated by ionogel electrolytes. Electrochemical doping in BBL induces ion pathways in amorphous regions during initial doping, facilitating efficient electron transport. This yields exceptional device performance, including a geometry-normalized transconductance of 4.6 S cm−1, an ON/OFF ratio of ≈105, a product of electron mobility and volumetric capacitance (μC* ≈ 16.4 F cm–1 V–1 s–1), and minimal hysteresis (<0.1 V). These features surpass most reported n-type EGTs, demonstrating the importance of ion-driven electrochemical doping in BBL. Furthermore, we not only fabricate all-polymer complementary inverters, NAND, and NOR gates but also demonstrate flexible circuits by integrating n-type BBL and p-type polythiophene EGTs.

Deformable optoelectronic devices are emerging as critical technologies for wearable healthcare systems and next-generation display and energy harvesting platforms. Their practical deployment, however, remains limited by accelerated degradation under ambient conditions. Penetration of water vapor and oxygen accelerates the failure of moisture-sensitive layers, making encapsulation a key determinant of operational lifetime. A fundamental trade-off exists between barrier performance and mechanical stretchability: organic materials offer high compliance but poor moisture resistance, whereas inorganic barriers provide excellent impermeability but suffer from brittleness. Addressing these competing requirements demands an integrated approach that considers material selection and fabrication methodology. This review highlights recent advances in stretchable encapsulation technologies, encompassing organic, inorganic, and hybrid materials, and outlines the core requirements for practical operation: high impermeability, mechanical compliance, and optical transparency. By correlating emerging experimental results with these criteria, this review establishes a framework for designing encapsulation strategies that reconcile mechanical and barrier demands.

Skin impedance reflects both the barrier function and psychophysiological state of the human body, but long-term monitoring remains challenging due to the lack of electrodes that simultaneously offer water resistance, stretchability, and breathability. In this study, we developed poly(vinyl alcohol)/waterborne polyurethane (PVA/WBPU) blend nanomesh electrodes with controlled polymer composition to address these requirements. Electrospinning produced nanofibers with an island–sea morphology, where partial dissolution of PVA enabled temporary skin adhesion while residual WBPU maintained structural integrity. The optimized PVA/WBPU = 5/5 electrodes showed minimal resistance increase (1.02-fold) after 24 h of continuous water flow and retained conductivity under 80% strain and after 1000 stretch cycles. When applied to the palm, they maintained stable resistance ( < 50 Ω) for at least 4 h, whereas PVA-only electrodes frequently exhibited resistance increases above 1 kΩ or electrical disconnection. These results indicate that controlling the PVA/WBPU blending ratio ensures mechanical and electrical stability while preserving breathability, establishing a materials design strategy for long-term, skin-conformable, and breathable bioelectronic interfaces.

Liquid metals (LMs) characterized with high conductivity and inherent deformability are potential materials for stretchable electronics and circuits. However, technological challenges associated with facile and efficient patterning of LMs currently impede their widespread implementation. Here, we present an environmentally friendly approach for the facile fabrication of stretchable conductors and circuits through the self-assembly of aqueous LM inks. This process leverages the anisotropic surface characteristics that drive the movement of the ink from hydrophobic to hydrophilic regions. Simultaneously, the ink with a stabilizer mitigated the premature deposition of LM particles. This culminated in the precise deposition of LM particles in accordance with the desired patterns on the substrate. The resulting LM patterns exhibit high resolution (<100 μm line width), high conductivity (2.0 × 10⁵ S m−1), and excellent electromechanical durability. Further demonstrated applications including stretchable displays, three-dimensional touch sensors and soft actuators showcase the versatility of this fabrication for stretchable electronics.

Two-dimensional (2D) materials offer unprecedented opportunities for energy-autonomous wearable electronics, yet their scalable and environmentally friendly integration into textiles remains a major challenge. Here, we introduce an ultrasonic spray-coating method to fabricate water-processable, surfactant-free 2D heterostructures comprising graphene and transition metal dichalcogenides (TMDs) as electronic dyes on textile fabrics. The resulting lightweight (~1 g/device), flexible textile-integrated triboelectric nanogenerators (TENGs) demonstrate a record-high power density of 793 mW m-2 among single-phase TMD-based textile devices. These TENGs enable self-powered, wearable detection of environmental and physiological parameters, including atmospheric humidity, body temperature, and volatile organic compounds (VOCs) such as acetone and styrene, via a tap-to-sense mechanism. The sensor achieves a record-breaking responsivity of 126% for styrene vapours, making it the first wearable, self-powered styrene sensor. The device’s multifunctionality – driven by thermal modulation of charge transport in the MoS2 layer – enables reliable body temperature detection with minimal cross-sensitivity to humidity or VOCs, crucial under real-world fluctuations. The sensor maintains mechanical resilience and operational stability over 80 days of continuous use and after 200 bending cycles. This work advances scalable, sustainable strategies for multifunctional, self-powered textile sensors and paves the way toward wearable personalised healthcare technologies with accurate multiparameter sensing.

Magnetic pressure sensors that employ magneto-elastomers to convert pressure stimuli into detectable magnetic signals are widely regarded as promising components for smart wearables. However, achieving both an ultralow detection limit and a broad sensing range within a single device remains a persistent challenge. Here, we present a magnetic amorphous-wire pressure sensor (MAWPS) that simultaneously attains these properties through a multilayer architecture designed to generate a tunable magnetic-field configuration. The device comprises a force-to-magnetic conversion unit (FMCU) and a magnetic sensing unit (MSU). The FMCU incorporates a composite magneto-elastomer formed by integrating cilia-type and film-type structures with opposite magnetization orientations. The magnetic cilia, characterized by low modulus, allows to detect subtle pressure, while the higher-modulus magnetic films modulate the intensity and direction of the magnetic field under larger pressure. This cooperative mechanism ensures that the magnetic field detected by magnetic amorphous wire of MSU remains within the sensitive range. As a result, the MAWPS exhibits a detection limit of 2.4 Pa, a sensing range exceeding 300 kPa, rapid response, and excellent stability. Furthermore, asymmetric wire placement enables shear-direction sensing ability. We further demonstrate the applicability in smart wearable scenarios, including respiratory monitoring, object grasping, morphology recognition, and stress direction sensing.

With technological advancements, consumer demands for textile functionality and intelligence have increased substantially. Next-generation E-textiles should enable multidirectional force sensing while ensuring high levels of wearer comfort. However, existing electronic textiles are insufficient to simultaneously monitor the direction and degree of strain, and sweat accumulation can lead to poor comfort. Here, inspired by the asymmetric gradient structure of human skin, Janus double-layer woven electronic textile (JDET) was designed. Through material-structure-function biomimetic design, bidirectional bending recognition and moisture management function are integrated into the device. A high-sensitivity strain sensing unit (GF = 1402.94) was constructed using a single wrapped yarn and conductive materials. Combined with a double-layer fabric structure design, a plain weave layer woven with hydrophilic sensing yarn and a twill weave layer woven with hydrophobic polyester yarn formed a dual gradient structure of fabric wettability and porosity, resulting in excellent unidirectional moisture transport capability. The asymmetric design of the sensing layer enables JDET to selectively identify bending directions (−180°–180°), and has good stability (>8000 s) in bending cycle testing. In addition, JDET has been successfully applied to human motion monitoring and Morse code interaction systems. This asymmetric gradient structure design of textiles provides ideas for the design of the next generation of intelligent electronic textiles.