搜索结果：Npj flexible electronics

Organic electrochemical transistors (OECTs) have emerged as essential components in various applications, including bioelectronics, neuromorphics, sensing, and flexible electronics. Recently, efforts have been directed toward developing flexible and sustainable OECTs to enhance their integration into wearable and implantable biomedical devices. In this work, we introduce a novel PEDOT:Sacran bio-nanocomposite as a channel material for flexible and biodegradable OECTs. Sacran, a high-molecular-weight polysaccharide derived from blue-green algae, possesses exceptional ionic conductivity, water retention, and biocompatibility, making it a promising candidate for bioelectronic applications. We successfully fabricated ultrathin and flexible OECTs on poly(ethylene terephthalate) (PET) foils, achieving transconductance values up to 7.4 mS. The devices exhibited stable ion-to-electron transduction after mechanical deformation. The OECTs were further demonstrated on eco-friendly and biodegradable poly(lactic acid) (PLA) substrates, achieving a transconductance of 1.6 mS and undergoing enzymatic hydrolysis under controlled conditions. This study highlights the potential of Sacran-based conductive bio-nanocomposites in advancing sustainable bioelectronic devices.

Ultrasound (US) imaging is a fundamental tool in healthcare for the diagnosis of diverse conditions. Wearable, flexible ultrasound patches could expand the scope of US imaging to continuous, at-home monitoring without professional intervention, but require scaling to large numbers of transducer elements. This poses challenges in interconnect density, power consumption, and data bandwidth. To improve interconnect density, we present the first integration of flexible ultrasound transducers with flexible a-IGZO thin-film transistor (TFT) multiplexing electronics. In the Si CMOS readout chip, a new circuit technique cuts front-end power, while a log-delta ADC compresses data efficiently. Our system achieves an 8× reduction in required front-end circuitry and a 42% decrease in front-end power. The data needed to describe the ultrasound image are reduced five-fold, decreasing data transmission power by the same factor. These advances bring the vision of wearable high-density, large-area ultrasound imaging patches for monitoring one step closer.

Transparent light detection devices are attractive for emerging see-through applications such as augmented reality, smart windows and optical communications using light fidelity (Li-Fi). Herein, we present flexible and transparent photodetectors (PDs) using conductive poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS): Ag nanowires (NWs) based nanofibres and zinc oxide (ZnO) NWs on a transparent and degradable cellulose acetate (CA) substrate. The electrospun (PEDOT:PSS): Ag NW-based nanofibres exhibit a sheet resistance of 11 Ω/sq and optical transmittance of 79% (at 550 nm of wavelength). The PDs comprise of ZnO NWs, as photosensitive materials, bridging the electrode based on conductive nanofibres on CA substrate. The developed PDs exhibit high responsivity (1.10 ×106 A/W) and show excellent stability under dynamic exposure to ultraviolet (UV) light, and on both flat and curved surfaces. The eco-friendly PDs present here can degrade naturally at the end of life - thus offering an electronic waste-free solution for transparent electrodes and flexible optoelectronics applications.

Organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxythiophene) (PEDOT) have been extensively studied, yet devices fabricated via electropolymerization remain underexplored in terms of the underlying ionic dynamics and the potential for flexible integration. In this work, we demonstrate robust OECTs based on electropolymerized PEDOT, exhibiting negligible drain current degradation after 1000 cycles of operation in aqueous NaCl. Compared to inkjet-printed devices, they offer markedly superior cycling stability, which is further enhanced by the incorporation of the small anionic dopant ClO4 -. We also show flexible, lightweight OECTs by electropolymerizing PEDOT on ultrathin parylene substrates, achieving stable performance under mechanical strain. Furthermore, Electrochemical Quartz Crystal Microbalance with Dissipation (EQCM-D) analysis reveals distinct ion transport behavior in PEDOT:ClO4, where dopant ejection dominates doping/dedoping process, unlike in PEDOT:PSS. This study underscores the advantages of electropolymerization and small-ion doping, offering new mechanistic insights and advancing the design of high-performance, flexible OECTs for bioelectronic applications.

The integration of flexible electronics and photonics has the potential to create revolutionary technologies, yet it has been challenging to marry electronic and photonic components on a single polymer device, especially through high-volume manufacturing. Here, we present a robust, chiplet-level heterogeneous integration of polymer-based circuits (CHIP), where several post-fabricated, ultrathin, polymer electronic, and optoelectronic chiplets are vertically bonded into one single chip at room temperature and then shaped into application-specific form factors with monolithic Input/Output (I/O). As a demonstration, we applied this process and developed a flexible 3D-integrated optrode with high-density arrays of microelectrodes for electrical recording and micro light-emitting diodes (μLEDs) for optogenetic stimulation while with unprecedented integration of additional temperature sensors for bio-safe operations and shielding designs for optoelectronic artifact prevention. Besides achieving simple, high-yield, and scalable 3D integration of much-needed functionalities, CHIP also enables double-sided area utilization and miniaturization of connection I/O. Systematic device characterization demonstrated the successfulness of this scheme and also revealed frequency-dependent origins of optoelectronic artifacts in flexible 3D-integrated optrodes. In addition to enabling excellent manufacturability and scalability, we envision CHIP to be generally applicable to numerous polymer-based devices to achieve wide-ranging applications.

Neural representations arise from the spatiotemporally structured activity of neuron populations, inherently residing in high-dimensional spaces. Writing specific information into the central nervous system requires precisely manipulating neural states within this framework. However, current neuromodulation methods lack the precision to fully address this complexity, presenting a significant challenge for advancing effective bidirectional interfaces. In this perspective, we advocate for high-dimensional stimulation as a systematic approach capable of approximating the high dimensionality of natural neural code for brain-machine interface applications. We outline key technological requirements on resolution, coverage, and safety, review recent advances in critical application areas, and highlight the promise of flexible electrode technology in enabling a transformative leap towards precise synthetic neural codes.

In recent years, wearable bioelectronics has rapidly expanded for diagnosing, monitoring, and treating various pathological conditions from the skin surface. Although the devices are typically prefabricated as soft patches for general usage, there is a growing need for devices that are customized in situ to provide accurate data and precise treatment. In this perspective, the state-of-the-art in situ fabricated wearable bioelectronics are summarized, focusing primarily on Drawn-on-Skin (DoS) bioelectronics and other in situ fabrication methods. The advantages and limitations of these technologies are evaluated and potential future directions are suggested for the widespread adoption of these technologies in everyday life.

Transient electronics offer a promising solution for reducing electronic waste and for use in implantable bioelectronics, yet their fabrication remains challenging. We report on a scalable method that synergistically combines chemical and photonic mechanisms to sinter printed Zn microparticles. Following reduction of the oxide layer using an acidic solution, zinc particles are agglomerated into a continuous layer using a flash lamp annealing treatment. The resulting sintered Zn patterns exhibit electrical conductivity values as high as 5.62 × 106 S m-1. The electrical conductivity and durability of the printed zinc traces enable the fabrication of biodegradable sensors and LC circuits: temperature, strain, and chipless wireless force sensors, and radio-frequency inductive coils for remote powering. The process allows for reduced photonic energy to be delivered to the substrate and is compatible with temperature-sensitive polymeric and cellulosic substrates, enabling new avenues for the additive manufacturing of biodegradable electronics and transient implants.

Composite structures with conformal coatings on porous backbones are widely employed in energy storage, flexible electronics, and biomedical devices. However, expansion-induced stresses can lead to mechanical degradation of the coatings, thereby limiting their performance. In this study, we use finite element simulations to evaluate how substrate morphology - including curvature, shape, and coating configuration - governs the mechanical response of expanding thin-film coatings, using lithiation of silicon anodes as a model case of extreme expansion. The peak stress and strain energy density of the expanding film are used as indicators of failure, and empirical relationships are introduced to predict their scaling with curvature. We find that films on shell-backbones consistently exhibit higher tensile stress but lower strain energy density than those on solid-backbones, reflecting a trade-off between cracking and delamination risks. In all studied configurations, substrates with positive Gaussian curvature amplify the in-plane stresses of the film and increase the propensity for mechanical degradation, whereas substrates with negative Gaussian curvature effectively redistribute stresses and enhance the mechanical resilience. This work highlights the advantages of shell-backbone saddle substrates for expanding thin-film systems and provides general guidelines for the design of mechanically robust architected composites and shell-based metamaterials.

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.

Large-area electronic sensor and actuator arrays are suitable systems for thin-film transistor (TFT) technology with numerous applications from consumer electronics to healthcare. Considerable effort is being spent to make these arrays a reality. However, research on the power delivery circuits that supply these arrays has remained largely unexplored. This work delves into the design trade-offs and characterization of high output power boost converters in low-temperature polysilicon (LTPS) technology. The proposed boost converters deliver 0.62-2.17 W of output power, orders of magnitude above prior TFT solutions, with efficiencies ranging from 47 to 69.5%. These boost converters enable the realization of large-area sensor and actuator arrays and set the foundation for future research in this area.

Neural interfaces that unify diagnostic and therapeutic functionalities hold particular promise for advancing both fundamental neuroscience and clinical neurotechnology. Functional ultrasound imaging (fUSI) has recently emerged as a powerful modality for high-resolution, non-invasive monitoring of brain function and structure. However, conventional metal-based microelectrodes typically impede ultrasound propagation, limiting compatibility with fUSI. Here, we present flexible, ultrasound-transparent neural interfaces that retain practical metal thicknesses while achieving high acoustic transparency. We introduce a theoretical and simulation-based framework to investigate the conditions under which commonly used polymers and metals in neural interfaces can become acoustically transparent. Based on these insights, we propose design guidelines that maximise ultrasound transmission through soft neural interfaces. We experimentally validate our approach through immersion experiments and by demonstrating the acoustic transparency of a suitably engineered interface using fUSI in phantom and in vivo experiments. Finally, we discuss the potential extension of this approach to therapeutic focused ultrasound (FUS). This work establishes a foundation for the development of multimodal neural interfaces with enhanced diagnostic and therapeutic capabilities, enabling both scientific discovery and translational impact.

Robotic intelligence has advanced greatly in the past decade. Nevertheless, integrating embodied intelligent and responsive behavior into soft robotic systems remains challenging because it typically requires bulky hardware for environmental feedback and decision-making. While soft materials like poly(N-isopropylacrylamide) (PNIPAM) offer potential for simplified material-based actuation through temperature-responsive motion, their slow response and high energy demands limit their use in closed-loop control systems. To overcome this limitation, we present soft PNIPAM-based actuators with integrated hydrogel-based Joule heating, enabling localized actuation without significantly altering the temperature within 1 cm of the actuator. The potential of the material is demonstrated by processing it into a soft gripper that can lift up to three-fold its own weight with integrated capability to adjust its actuation in response to the gripped object. This design is well-suited for energy-efficient manipulation and sorting of delicate items, such as those found in automated packaging systems.

Implant-associated infections (IAIs) arise from immune dysregulation and the resilience of bacterial biofilms, which create a permissive niche for persistent infection. Biofilms further suppress host immunity and impair repair. Advances in nanoengineered surfaces and multifunctional antimicrobial coatings, together with gas-releasing and stimulus-responsive nanoplatforms, offer effective non-antibiotic strategies to inhibit colonization, disrupt biofilms, and modulate local immunity. This review summarizes emerging immune-informed approaches for treating IAIs.

Seals exhibit exceptional ability to navigate and detect underwater prey with high precision, even in complete darkness using their ultra-sensitive whiskers. These whiskers combine two key adaptations: undulatory morphology, which suppresses self-induced vibrations and rhythmic whisking, which actively probes surrounding water. Most previous studies of whisker-based hydrodynamic sensing focused on static artificial whiskers, leaving the functional role of whisking largely unexplored. We show that undulated harbor seal whiskers exhibit threefold lower vortex-induced vibrations (VIV) and over fiftyfold higher signal-to-noise ratio (SNR) than California sea lion whiskers. To study the functional role of whisking in the sensing performance of the whiskers, an artificial muscle comprised of an electrohydraulic soft actuator was integrated at the base of a natural whisker, allowing precise stiffness control and rhythmic whisking. Finally, we developed a bionic seal muzzle with 30 natural whiskers per side, capable of whisking at variable angles and frequencies, closely mimicking natural dynamics. Our results indicate that undulatory morphology and active whisker protraction are essential for seals to achieve sufficiently high SNR to track prey trails.

Airway stents play a vital role in managing central airway obstruction (CAO) caused by lung cancer and other pulmonary diseases by providing structural support to collapsed airways and restoring airflow. However, complications such as stent migration often require urgent medical intervention while early monitoring is essential to reduce the risk. Regular monitoring through bronchoscopy requires anesthesia in the hospital, which causes pain and an economic burden on patients. Computed tomography involves risky radiation and lacks the ability to provide continuous, real-time feedback outside of hospital settings. Here we report a fundamental mechanism of wireless tracking based on magnetic field in a wirelessly powered sensory ring integrated on an airway stent. The sensory ring is designed for continuous, real-time monitoring of stent position and orientation. This sensory ring, integrating an on-board magnetic sensor, and a wearable magnetic field generation system, enable accurate localization by detecting the magnetic field generated externally. The sensory ring is powered wirelessly via a charging coil, ensuring long-term operation. Our system achieves tracking accuracy of 0.5 mm and 2.2 degrees, with a temporal resolution of 0.2 Hz. Beyond migration monitoring, the sensor also detects airway deformation, offering the potential to sense pathological changes associated with lung cancer and other pulmonary conditions. By eliminating the need for radiation-based imaging or bronchoscopy, this approach enables safe, long-term surveillance of stent patency and surrounding tissue conditions. The proposed sensing mechanism and platform are also adaptable in other organs, such as the esophagus, for monitoring stent migration and deformation.

Contemporary cardiac and heart rate monitoring devices capture physiological signals using optical and electrode-based sensors. However, these devices generally lack the form factor and mechanical flexibility necessary for use in ambulatory and home environments. Here, we report an ultrathin (~1 mm average thickness) and highly flexible wearable cardiac sensor (WiSP) designed to be minimal in cost (disposable), light weight (1.2 g), water resistant, and capable of wireless energy harvesting. Theoretical analyses of system-level bending mechanics show the advantages of WiSP's flexible electronics, soft encapsulation layers and bioadhesives, enabling intimate skin coupling. A clinical feasibility study conducted in atrial fibrillation patients demonstrates that the WiSP device effectively measures cardiac signals matching the Holter monitor, and is more comfortable. WiSP's physical attributes and performance results demonstrate its utility for monitoring cardiac signals during daily activity, exertion and sleep, with implications for home-based care.

Intracortical microelectrodes are used for recording activity from individual neurons, providing both a valuable neuroscience tool and an enabling medical technology for individuals with motor disabilities. Standard neural probes carrying the microelectrodes are rigid silicon-based structures that can penetrate the brain parenchyma to interface with the targeted neurons. Unfortunately, within weeks after implantation, neural recording quality from microelectrodes degrades, owing largely to a neuroinflammatory response. Key contributors to the neuroinflammatory response include mechanical mismatch at the device-tissue interface and oxidative stress. We developed a mechanically-adaptive, resveratrol-eluting (MARE) neural probe to mitigate both mechanical mismatch and oxidative stress and thereby promote improved neural recording quality and longevity. In this work, we demonstrate that compared to rigid silicon controls, highly-flexible MARE probes exhibit improved recording performance, more stable impedance, and a healing tissue response. With further optimization, MARE probes can serve as long-term, robust neural probes for brain-machine interface applications.

Skin-inspired soft and stretchable electronic devices based on functional nanomaterials have broad applications such as health monitoring, human-machine interface, and the Internet of things. Solution-processed conductive nanocomposites have shown great promise as a building block of soft and stretchable electronic devices. However, realizing conductive nanocomposites with high conductivity, electromechanical stability, and low modulus over a large area at sub-100 μm resolution remains challenging. Here, we report a moldable, transferrable, high-performance conductive nanocomposite comprised of an interpenetrating network of silver nanowires and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate). The stacked structure of the nanocomposite synergistically integrates the complementary electrical and mechanical properties of the individual components. We patterned the nanocomposite via a simple, low-cost micromolding process and then transferred the patterned large-area electrodes onto various substrates to realize soft, skin-interfaced electrophysiological sensors. Electrophysiological signals measured using the nanocomposite electrodes exhibit a higher signal-to-noise ratio than standard gel electrodes. The nanocomposite design and fabrication approach presented here can be broadly employed for soft and stretchable electronic devices.