Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing

Recent advances in smart hydrogels derived from polysaccharides and their applications for wound dressing and healing

Owing to their inherent biocompatibility and biodegradability, hydrogels derived from polysaccharides have emerged as promising candidates for wound management. However, the complex nature of wound healing often requires the development of smart hydrogels---intelligent materials capable of responding dynamically to specific physical or chemical stimuli. Over the past decade, an increasing number of stimuli-responsive polysaccharide-based hydrogels have been developed to treat various types of wounds. While a range of hydrogel types and their versatile functions for wound management have been discussed in the literature, there is still a need for a review of the crosslinking strategies used to create smart hydrogels from polysaccharides. This review provides a comprehensive overview of how stimuli-responsive hydrogels can be designed and made using five key polysaccharides: chitosan, hyaluronic acid, alginate, dextran, and cellulose. Various methods, such as chemical crosslinking, dynamic crosslinking, and physical crosslinking, which are used to form networks within these hydrogels, ultimately determine their ability to respond to stimuli, have been explored. This article further looks at different polysaccharide-based hydrogel wound dressings that can respond to factors such as reactive oxygen species, temperature, pH, glucose, light, and ultrasound in the wound environment and discusses how these responses can enhance wound healing. Finally, this review provides insights into how stimuli-responsive polysaccharide-based hydrogels can be developed further as advanced wound dressings in the future.

An NIR-responsive "4A hydrogel" encapsulating wormwood essential oil: through antibacterial, antioxidant, anti-inflammation, and angiogenic to promote diabetic wound healing

The incorporation of hydrogels with biocompatible functional components to develop wound dressings exhibiting potent antibacterial, antioxidant, anti-inflammatory, and angiogenic properties to promote diabetic wound healing is highly desirable yet continues to pose a significant challenge. In this study, wormwood essential oil (WEO) is successfully encapsulated within black phosphorus (BP) using a physical extrusion technique. Subsequently, this composite is encapsulated within biocompatible gelatin methacrylate (GelMA) and hyaluronic acid methacrylate (HAMA) hydrogels to create multifunctional hydrogel dressing (WEO@BP/GH). In comparison to traditional hydrogels, BP enhances the encapsulation stability of WEO and improves the microenvironmental regulation capabilities through NIR-triggered release of WEO. Systemic in vitro experiments demonstrate that synergistic interaction between the diverse bioactive components of WEO and photothermal effects of BP results in highly effective antibacterial activities against S. aureus and E. coli, antioxidant of scavenging ROS, anti-inflammation of downregulating M1/M2 macrophages ratio, and angiogenic properties. Moreover, the in vivo tests demonstrate that WEO@BP/GH hydrogel significantly enhances high-performance diabetic wound repair through the acceleration of hemostasis, promotion of collagen deposition, regulation of inflammatory responses, and facilitation of vascularization. The findings indicate that WEO@BP/GH hydrogel holds considerable promise as a candidate for microenvironment regulation and effective diabetic wound healing across various clinical applications.

Thermo-responsive and phase-separated hydrogels for cardiac arrhythmia diagnosis with deep learning algorithms

Adhesive epidermal hydrogel electrodes are essential for achieving robust signal transduction and cardiac arrhythmia diagnosis, but detachment of conventional adhesive dressings easily causes secondary damage to delicate wound tissues due to lack of programmable capability of changed adhesion. Herein, we developed hydrogel-based skin-interfacing electrodes capable of on-demand programmable adhesion and detachment to capture electrocardiogram signals for diagnosing cardiac arrhythmia. This was achieved by integrating dynamic multiscale contact and coordinated regulation through temperature-mediated switchable hydrogen bond interactions in phase-separated smart hydrogels. Through micro-scale regulation of adhesive molecules and meso-scale modulation of the modulus, the hydrogel electrodes can be rapidly transited between a slippery state (adhesion ∼1.3 N/m) and a sticky one (adhesion ∼110 N/m) during its peeling from skin. This achieves an 84.5-fold increase of on/off adhesive energy (or reducing the adhesion at the skin interface by 98%) at low temperatures compared to normal skin temperature. A real-time cloud platform was developed by integrating hydrogel electrodes, enabling remote electrocardiogram (ECG) monitoring. For clinical applications, such developed skin sensing platform effectively captured cardiac activities in patients with eight common arrhythmias, achieving by the recorded high-fidelity and analyzable electrical signals. With the assistance of deep learning algorithms, we demonstrated a wearable cardiac arrhythmia intelligent diagnosis system which enables real-time conversion of the collected ECG data into diagnostic evaluations with a recognition accuracy of 98.5%.

An Intelligent and Conductive Hydrogel with Multiresponsive and ROS Scavenging Properties for Infection Prevention and Anti-Inflammatory Treatment Assisted by Electrical Stimulation for Diabetic Wound

Diabetic wounds experience a hyperglycemic, hypoxic environment, combined with ongoing oxidative stress and inflammatory imbalances, significantly disrupts normal healing process. Advanced hydrogels have been considered one of the most exciting medical biomaterials for the potential in wounds healing. Herein, a novel conductive hydrogel (HEPP), designed to release nanozyme (PTPPG) in response to its microenvironment, was created to facilitate glucose (Glu) catabolism. Furthermore, the HEPP integrates photodynamic therapy (PDT), photothermal therapy (PTT), and self-cascading reactive oxygen species (ROS) to prevent bacterial infections while ensuring a continuous supply of oxygen (O2) to the wound. The HEPP not only adeptly controls high ROS levels, but also enhances the regulation of inflammation in the wound area via electrical stimulation (ES), thereby promoting healing that is supported by the immune response. Studies conducted in vitro, along with transcriptomic analyses, indicate that ES primarily mitigates inflammation by regulating Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The effects of HEPP combined with ES are primarily connected to their impact on TNF signaling pathways. By reducing the formation of ROS and employing ES to effectively lessen inflammation, this approach offers an innovative method to manage complicated diabetic wounds, ulcers, and a range of inflammatory conditions linked to infections.

Ionic conducting hydrogels as biomedical materials: classification, design strategies, and skin tissue engineering applications

Ionically conductive hydrogels (ICHs) are considered promising flexible electronic devices and various wearable sensors due to the integration of the conductive performance and soft nature of human tissue-like materials with mechanical and sensory traits. Recently, substantial progress has been made in the research of ICHs, including high conductivity, solution processability, strong adhesion, high stretchability, high self-healing ability, and good biocompatibility. These advanced researches also promote their excellent application prospects in medical monitoring, sports health, smart wear, and other fields. This article reviewed ICHs' current classification and design strategies in biomedical applications and the structure-activity relationship of the interface between biological systems and electronics. Furthermore, the typical cases of frontiers of skin interface applications of ICHs were elaborated in transdermal drug delivery, wound healing, disease diagnosis and treatment, and human-computer interaction. This article aims to inspire related research on ionically conductive hydrogels in the biomedical field and promote the innovation and application of flexible wearable electronic device technology.

Advancements in flexible porous Nanoarchitectonic materials for biosensing applications

The development of nanoporous materials has gained significant attention due to their unique structural properties and multimodalities, which are highly relevant for advanced sensing technologies. The capability to directly grow nanoporous materials on flexible substrates or indirectly integrate them into soft templates through mixing and dispersion opens exciting opportunities for a new class of flexible and stretchable electronics for personalized healthcare applications. This review paper provides a snapshot of recent advancements in flexible nanoporous materials and their applications, emphasizing biological and biomedical sensors. The review highlights the material of choice for flexible and stretchable substrates and effective approaches to synthesize and integrate nanoporous architectures onto soft polymers. Applications from wearable sweat sensors, mechanical sensors for electronic skins, implantable bioelectronics, and gas sensing are also presented. The paper concludes with current challenges and future perspectives within this highly active research paradigm.

Recent Progress of Soft and Bioactive Materials in Flexible Bioelectronics

Materials that establish functional, stable interfaces to targeted tissues for long-term monitoring/stimulation equipped with diagnostic/therapeutic capabilities represent breakthroughs in biomedical research and clinical medicine. A fundamental challenge is the mechanical and chemical mismatch between tissues and implants that ultimately results in device failure for corrosion by biofluids and associated foreign body response. Of particular interest is in the development of bioactive materials at the level of chemistry and mechanics for high-performance, minimally invasive function, simultaneously with tissue-like compliance and in vivo biocompatibility. This review summarizes the most recent progress for these purposes, with an emphasis on material properties such as foreign body response, on integration schemes with biological tissues, and on their use as bioelectronic platforms. The article begins with an overview of emerging classes of material platforms for bio-integration with proven utility in live animal models, as high performance and stable interfaces with different form factors. Subsequent sections review various classes of flexible, soft tissue-like materials, ranging from self-healing hydrogel/elastomer to bio-adhesive composites and to bioactive materials. Additional discussions highlight examples of active bioelectronic systems that support electrophysiological mapping, stimulation, and drug delivery as treatments of related diseases, at spatiotemporal resolutions that span from the cellular level to organ-scale dimension. Envisioned applications involve advanced implants for brain, cardiac, and other organ systems, with capabilities of bioactive materials that offer stability for human subjects and live animal models. Results will inspire continuing advancements in functions and benign interfaces to biological systems, thus yielding therapy and diagnostics for human healthcare.

Electrical hydrogel: electrophysiological-based strategy for wound healing

Wound healing remains a significant challenge in clinical practice, driving ongoing exploration of innovative therapeutic approaches. In recent years, electrophysiological-based wound healing strategies have gained considerable attention. Specifically, electrical hydrogels combine the synergistic effects of electrical stimulation and hydrogel properties, offering a range of functional benefits for wound healing, including antibacterial activity, real-time wound monitoring, controlled drug release, and electrical treatment. Despite significant progress made in electrical hydrogel research for wound healing, there is a lack of comprehensive, systematic reviews summarizing this field. In this review, we survey the latest advancements in electrical hydrogel technology. After analyzing the mechanisms of electrical stimulation in promoting wound healing, we establish a novel classification framework for electrical hydrogels based on their operational principles. The review further provides an in-depth evaluation of the therapeutic efficacy of these hydrogels in various types of wounds. Finally, we propose future directions and challenges for the development of electrical hydrogels for wound healing.

Smart bandages for wound monitoring and treatment

Wound management plays a crucial role in nursing care as it facilitates effective wound healing and prevents infections. To overcome limitations associated with traditional treatment methods, various smart bandages have been developed. The monitoring of wound parameters and the implementation of targeted treatments are crucial aspects of smart bandage development. Smart bandages, as cutting-edge flexible wearable medical devices, integrate various sensing technologies, providing new insights for dynamic monitoring and personalized treatment of chronic wounds. This paper systematically summarizes the applications and developments of smart bandages in monitoring wound environmental parameters, focusing on two major detection methods: colorimetric sensing and electrochemical sensing. Colorimetric sensors typically rely on color changes induced by physiological parameters, which can not only be identified by the naked eye but also combined with image recognition algorithms for physiological parameter detection. Electrochemical sensors, on the other hand, modify electrodes with specific enzymes and detect physiological parameters through the electrical signals generated by redox reactions. In addition to sensing, this paper further explores the integrated application of three smart therapeutic strategies in smart bandages, including promoting cell proliferation and angiogenesis through electrical stimulation, achieving controlled drug release via responsive materials, and utilizing photothermal materials for efficient antibacterial treatment of wounds. Finally, the paper delves into the challenges these bandages face in system integration and clinical translation, and discusses their potential in personalized wound care.

A microfluidic wearable device for wound exudate management and analysis in human chronic wounds

Chronic wounds are a major global health challenge associated with substantial economic burden and a negative impact on patient quality of life. Real-time analysis of biomarkers like reactive oxygen and nitrogen species could guide treatment, but existing systems lack the capacity required for continuous monitoring. Wound exudate is secreted slowly and has a complex composition, making efficient fluid collection and real-time analysis challenging. To address these issues, we introduce iCares, a wearable device for wound exudate management and continuous in situ analysis of wound biomarkers. iCares contains a flexible nanoengineered sensor array that measures reactive species such as NO, H2O2, and O2, along with pH and temperature, providing multiparameter data to inform wound status. The device features pump-free triad microfluidic modules with a superhydrophobic-superhydrophilic Janus membrane, bioinspired wedge channels, and three-dimensional graded micropillars for efficient unidirectional exudate collection, transport, and refreshing. The sensors demonstrated a consistent response and analyte selectivity in vitro and in wound exudate. iCares was designed for rapid scalable manufacturing through advanced printing and laser patterning. Wireless connectivity supported long-term continuous monitoring in wounds. The iCares system real-time monitoring was tested in a murine model of diabetic skin wound during infection and antimicrobial treatment. Clinical wound evaluation was conducted in 20 patients with chronic wounds and in two patients before and after surgery. A machine learning analysis of the multiplexed data successfully classified wounds and healing times, indicating that wound exudate analysis by iCares could offer insight into chronic wound status to aid in treatment decisions.

Pd@Au Nanoframe Hydrogels for Closed-Loop Wound Therapy

In this work, a multifunctional Pd@Au nanoframe hydrogel was designed to detect uric acid (UA) for in situ monitoring of wound infection and enhance wound healing by a chemo-photothermal strategy. In acidic conditions, the Pd@Au nanoframe hydrogels show high peroxidase-like activity by catalyzing H2O2 to produce reactive oxygen species (ROS) to damage RNAs of bacteria and enhance antibacterial activity. Under Near-infrared (NIR) laser irradiation, the Pd@Au nanoframe hydrogels exhibit photothermal conversion performance; i.e., the color of Pd@Au nanoframe hydrogel solution varies from deep blue (0 s, 25.4 °C) to red (300 s, 50.1 °C) in infrared thermography. After loading the antibacterial mupirocin (M), the as-obtained M Pd@Au nanoframe hydrogels show a maximum cumulative release rate exceeding 90% for mupirocin, as controlled by NIR laser irradiation. In antimicrobial experiments in vitro, M Pd@Au nanoframe hydrogels exhibit NIR laser-driven antibacterial ability; i.e., 98% Escherichia coli are effectively killed in 10 min. After coating rabbit wounds with a UA sensing patch of M Pd@Au nanoframe hydrogels, wound status can be monitored in real time by detecting UA concentration, leading to rapid wound healing in 4 days by a new synergistic effect of chemo-photothermal strategy. This approach successfully confirms a closed-loop strategy, i.e., real-time monitoring the status of a wound and efficiently perform chemo-photothermal wound therapy, for wound healing by combining functional hydrogels, NIR laser irradiation, and pharmaceutical antibacterials.

Interpretable Machine Learning for Evaluating Nanogenerators' Structural Design

The limited battery life in modern mobile, wearable, and implantable electronics critically constrains their operational longevity and continuous use. Consequently, as a self-powered technology, triboelectric nanogenerators (TENGs) have emerged as a promising solution to this. Traditional approaches for evaluating TENG structural design typically require manual, repetitive, time-consuming, and high-cost finite element modeling or experiments. To overcome this bottleneck, we developed a fully automated platform that leverages machine learning (ML) techniques. Our framework contains an artificial neuron network-based surrogate model that can provide accurate and reliable performance predictions for any structural parameters and a TreeSHAP interpretable ML model that can generate precise global and local insights for TENG structural parameters. Our platform shows broad adaptability to multiple TENG structures. In summary, our platform is an integrated platform that utilizes interpretable ML techniques to solve the complex multidimensional TENG structural evaluation problem, marking a significant advancement in TENG design and supporting sustainable energy solutions in mobile electronics.

Self-Manipulating Sodium Ion Gradient-Based Endogenic Electrical Stimulation Dressing for Wound Repair

Endogenous electric field (EF) originating from differences in ionic gradients plays a decisive role in the wound healing process. Based on this understanding, a self-manipulating sodium ion gradient-based endogenic electrical stimulation dressing (smig-EESD) is developed to achieve passive, non-invasive, endogenic electrical stimulation of wounds, which avoids the side effects of electrode occupancy, electrochemical reactions, and thermal effects present in traditional exogenous electrical stimulation. smig-EESD reduced the potential at the center of the wound by specifically absorbing Na+ in the exudate, ultimately strengthening the wound endogenous EF. Importantly, smig-EESD converted the active transport dependent on Na+/K+-ATPase into passive diffusion by adsorbing extracellular matrix Na+, and the saved ATP consumption promoted tissue repair process. smig-EESD regulated innate and adaptive immune responses by upregulating the secretion of multiple cytokines, thereby suppressing injury-associated inflammatory responses and reducing scar formation. smig-EESD reveals an endogenic electrical stimulation strategy that is independent of electrodes and circuits, and provides new insights into the future development of electronic medicine.

High-Conductivity, Self-Healing, and Adhesive Ionic Hydrogels for Health Monitoring and Human-Machine Interactions Under Extreme Cold Conditions

Ionic conductive hydrogels (ICHs) are emerging as key materials for advanced human-machine interactions and health monitoring systems due to their unique combination of flexibility, biocompatibility, and electrical conductivity. However, a major challenge remains in developing ICHs that simultaneously exhibit high ionic conductivity, self-healing, and strong adhesion, particularly under extreme low-temperature conditions. In this study, a novel ICH composed of sulfobetaine methacrylate, methacrylic acid, TEMPO-oxidized cellulose nanofibers, sodium alginate, and lithium chloride is presented. The hydrogel is designed with a hydrogen-bonded and chemically crosslinked network, achieving excellent conductivity (0.49 ± 0.05 S m-1), adhesion (36.73 ± 2.28 kPa), and self-healing capacity even at -80 °C. Furthermore, the ICHs maintain functionality for over 45 days, showcasing outstanding anti-freezing properties. This material demonstrates significant potential for non-invasive, continuous health monitoring, adhering conformally to the skin without signal crosstalk, and enabling real-time, high-fidelity signal transmission in human-machine interactions under cryogenic conditions. These ICHs offer transformative potential for the next generation of multimodal sensors, broadening application possibilities in harsh environments, including extreme weather and outer space.

Sensorable zwitterionic antibacterial hydrogel for wound electrostimulation therapy

Wound healing process has always been a focal point of concern, with a plethora of hydrogel dressings available; however, their therapeutic efficacy remains a hindrance to wound closure. This article reports on a dual-network conductive system, PEDOT:PSS-co-PSBMA/XLG (PPSX) hydrogel dressing, Constructed using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT: PSS) in combination with zwitterionic N, N-dimethyl-N-(2-methacryloyloxyethyl)-N- (3-sulfopropyl) ammonium betaine (SBMA) and nanoclay-synthesized lithium magnesium silicate (XLG). The hydrogel powder produced from it can absorb interfacial water within 30 s via physical interactions to spontaneously form hydrogels of arbitrary shapes. With a conductivity of 1.8 s/m, it can be utilized for developing flexible sensing bioelectronic devices to monitor human activities (facial expressions, blinking, swallowing, speaking, joint movements), as well as constructing electrodes for monitoring muscle movements and motorial intensity. More importantly, PPSX hydrogel effectively inhibits bacterial growth and promotes cell proliferation, thus facilitating wound healing and presenting extensive application prospects in the medical field.

Hierarchical Porous Aerogel-Hydrogel Interlocking Bioelectronic Interface for Arrhythmia Management

Carbon aerogels with exceptional electrical properties are considered promising materials for bioelectronics in signal detection and electrical stimulation. To address the mechanical incompatibilities of carbon aerogels with bio-interfaces, particularly for dynamic tissues and organs, the incorporation of hydrogels is an effective strategy. However, achieving excellent electrical performance in carbon aerogel-hydrogel hybrids remains a significant challenge. Two key factors contribute to this difficulty: 1) unrestricted hydrogel infiltration during preparation can lead to complete encapsulation of the conductive aerogel, and 2) the high swelling behavior of hydrogels can cause disconnection of the aerogel. Herein, a stretchable, highly conductive bioelectronic interface is achieved by forming an interlocking network between hierarchical porous carbon aerogel (PA) with polyvinyl alcohol (PVA) hydrogel. Partial exposure of the PA due to confined infiltration of PVA into the porous structure maintains the electrical performance, while the non-swellable PVA ensures mechanical stretchability and stability. The hybrid demonstrates excellent conductivity (370 S·m-1), high charge storage capacity (1.66 mC cm-2), remarkable stretchability (250%), and long-term stability over three months, enabling effective signal recording and electrical stimulation. For the first time, carbon aerogel-hydrogel hybrids enable cardiac pacing both ex vivo and in vivo in rat heart models. Compared to conventional platinum electrodes, the PA-PVA electrodes require lower pacing voltages, suggesting potential advantages in power efficiency and reduced tissue damage. The electrodes can be integrated with a wireless implantable device for in vivo synchronous electrocardiogram monitoring and cardiac pacing, underscoring their potential for arrhythmia management.

Electric spiking activity in epithelial cells

Epithelial cells (human keratinocyte cells and the canine MDCK cell line), traditionally viewed as electrically non-self-excitable and involved primarily in physiological functions such as barrier presentation, absorption, secretion, and protection, are shown here to exhibit traveling extracellular electric charge when they recover from spatially focused, laser-induced wounding of confluent monolayers cultured on a multielectrode array chip. Voltage spikes measured on these electrodes display depolarization, repolarization, and hyperpolarization phases with amplitudes similar to the action potentials of neurons but with the markedly slower duration of 1 to 2 s. Some propagate distances up to hundreds of μm from the wound with a mean speed of around 10 mm s-1. Generation and transmission of bioelectric signals are significantly influenced by the perturbation of mechanosensitive cationic ion channels. These direct measurements confirm bioelectric signaling that previous work has hypothesized to regulate epithelial cell development and may have relevance to the frequency parameter selection of bioelectric devices.

Autonomous Bioelectronic Devices Based on Silk Fibroin

The development of autonomous bioelectronic devices capable of dynamically adapting to changing biological environments represents a significant advancement in healthcare and wearable technologies. Such systems draw inspiration from the precision, adaptability, and self-regulation of biological processes, requiring materials with intrinsic versatility and seamless bio-integration to ensure biocompatibility and functionality over time. Silk fibroin (SF) derived from Bombyx mori cocoons, has emerged as an ideal biomaterial with a unique combination of biocompatibility, mechanical flexibility, and tunable biodegradability. Adding autonomous features into SF, including self-healing, shape-morphing, and controllable degradation, enables dynamic interactions with living tissues while minimizing immune responses and mechanical mismatches. Additionally, structural tunability and environmental sustainability of SF further reinforce its potential as a platform for adaptive implants, epidermal electronics, and intelligent textiles. This review explores recent progress in understanding the structure-property relationships of SF, its modification strategies, and its great potential for integration into advanced autonomous bioelectronic systems while addressing challenges related to scalability, reproducibility, and multifunctionality. Future opportunities, such as AI-assisted material design, scalable fabrication techniques, and the incorporation of wireless and personalized technologies, are also discussed, positioning SF as a key material in bridging the gap between biological systems and artificial technologies.

Combined treatment strategy of hydrogel dressing and physiotherapy for rapid wound healing

Wound care for open wounds is essential for reducing pain, protecting open wounds, speeding up the healing process and avoiding scar formation. Among the various three-dimensional (3D) carrier biomaterials such as films, sponges, and hydrogels, hydrogels are chemically and physically most similar to the natural extracellular matrix (ECM). Meanwhile, hydrogels are also common 3D carriers that can be efficiently loaded with drugs or cells. In addition, it forms a protective barrier on the wound surface to prevent secondary external infections and has the effect of directing skin cell expansion, tissue infiltration, and wound closure. However, the role of functional drugs in wound healing also faces a number of issues such as resistance, dosage, activity, and stability; therefore, a richer array of therapies is needed for wound repair and other areas of development. Physiotherapy, also known as nonpharmacological therapy, is a commonly used clinical treatment. Recently, more and more physiotherapy have been used for wound repair due to their high efficiency and low irritation. In recent reports, many researchers have tended to use hydrogel dressings in combination with physiotherapy, and this combination therapy is beneficial because it can both protect the wound microenvironment and accelerates wound healing. Therefore, this paper reviews the combined use of hydrogel dressings and physiotherapy in wound healing. We present the characteristics of hydrogel and physiotherapy and focus on the progress and problems of these two combined therapies in recent years.

Wearable flexible ultrasound microneedle patch for cancer immunotherapy

Clinical approaches for cancer therapy face several interrelated challenges involving inefficient drug delivery, potential adverse side effects, and inconvenience. Here, we present an integrated wearable flexible ultrasound microneedle patch (wf-UMP) that serves as a portable platform for convenient, efficient, and minimally invasive cancer therapy. The wf-UMP adopts an all-in-one bioelectronic concept, which integrates a stretchable lead-free ultrasound transducer array for acoustic emission, a bioadhesive hydrogel elastomer for robust adhesion and acoustic coupling, and a dissolvable microneedle patch loaded with biocompatible piezoelectric nanoparticles for painless drug delivery and reactive oxygen species generation. With soft mechanical properties and enhanced electromechanical performance, wf-UMP can be robustly worn on curved and dynamic tissue surfaces for easy and effective manipulation. In preclinical studies involving mice, wf-UMP demonstrated notable anticancer effects by inducing tumor cell apoptosis, amplifying oxidative stress, and modulating immune cell proliferation. Furthermore, the synergistic immunotherapy induced by wf-UMP and Anti-PD1 further improved anticancer immunity by activating immunogenic cell death and regulating macrophages polarization, inhibiting distant tumor growth and tumor recurrence.

Toughening hydrogels through a multiscale hydrogen bonding network enabled by saccharides for a bio-machine interface

Hydrogels have considerably emerged in a variety of fields, but their weak mechanical properties severely restrict the wide range of implementation. Herein, we propose a multiscale hydrogen bonding toughening strategy using saccharide-based materials to optimize the hydrogel network. The monosaccharide (glucose) at the molecular scale and polysaccharide (cellulose nanofibrils) at the nano/micro scale can effectively form hydrogen bonds across varied scales within the hydrogel network, leading to significantly enhanced mechanical properties. Besides, the toughened hydrogels present excellent environmental resilience and bad solvent resistance, allowing them to retain their performance in various severe environments. Notably, after being exchanged with a bad solvent such as ethanol, the alcogel exhibits strain-depended vivid interference color, allowing it to function as a mechano-optical sensor. Finally, this strategy has been shown to be adaptable across multiple material systems, and the resulting hydrogels have potential as a bioelectronic interface for long-term stable recording of physiological signals, highlighting the potential of sustainable biomaterials in designing high-quality hydrogels for advanced applications.

Bioinspired Supramolecular Dressing of Adaptable Programmability and Multifunctionality for Wound Healing

As the largest organ in the human body, the skin plays a crucial role in protecting tissues from external threats. Damage in the skin can not only lead to bleeding and increase the risk of infection and inflammation but also result in tissue necrosis and scar formations. Therefore, wound dressings of high efficiency and intrinsic biocompatibility are essential for defending the wound sites and promoting healing. However, the state-of-the-art wound dressings have intrinsic shortcomings in curing, which would exudate due to limited water absorption capacity and the adhesion side effect, which may cause secondary damages. There remains a gap in the availability of wound dressings that simultaneously integrate antibacterial, self-healing, biodegradable, and temperature-sensitive properties. Herein, a bioinspired supramolecular hydrogel-based wound dressing composed of a KYD (KYDYKYDYKK) self-assembly peptide-agar double-network is developed with the assistance of 3D printing. The reversible self-assembling dynamics of the KYD along with the existence of lysine residues endow the double-networks with the ability of self-healing and antibacterial properties, while the introduction of agar allows the bioinspired system to be temperature sensitive. In addition, the grid size of the bioinspired dressing is light-stimulated and adaptable, allowing for real-time control of air permeability. Combined with intrinsic biodegradability, the multifunctional supramolecular wound dressing enables sustainable drug releases. Consequently, the programmability of strength, flexibility, and performances in this design ensures customizability in a variety of wound conditions of the bioinspired supramolecular wound dressing, thus showing promising potential in enhancing clinical wound management and improving patient lifecare.

Intrinsically Adhesive and Conductive Hydrogel Bridging the Bioelectronic-Tissue Interface for Biopotentials Recording

Achieving high-quality biopotential signal recordings requires soft and stable interfaces between soft tissues and bioelectronic devices. Traditional bioelectronics, typically rigid and dependent on medical tape or sutures, lead to mechanical mismatches and inflammatory responses. Existing conducting polymer-based bioelectronics offer tissue-like softness but lack intrinsic adhesion, limiting their effectiveness in creating stable, conductive interfaces. Here, we present an intrinsically adhesive and conductive hydrogel with a tissue-like modulus and strong adhesion to various substrates. Adhesive catechol groups are incorporated into the conductive poly(3,4-ethylenedioxythiophene) (PEDOT) hydrogel matrix, which reduces the PEDOT size and improves dispersity to form a percolating network with excellent electrical conductivity and strain insensitivity. This hydrogel effectively bridges the bioelectronics-tissue interface, ensuring pristine signal recordings with minimal interference from bodily movements. This capability is demonstrated through comprehensive in vivo experiments, including electromyography and electrocardiography recordings on both static and dynamic human skin and electrocorticography on moving rats. This hydrogel represents a significant advancement for bioelectronic interfaces, facilitating more accurate and less intrusive medical diagnostics.

A Wireless Operated Flexible Bioelectronic Microneedle Patch for Actively Controlled Transdermal Drug Delivery

Precise control over drug release rates is critical for enhancing therapeutic efficacy, reducing side effects, and maintaining stable drug levels. While microneedles (MNs) offer a promising approach for transdermal drug delivery, conventional passive-response systems often lack adaptability across diverse drugs and disease models, limiting their versatility. Here, this work presents a flexible bioelectronic microneedle patch (FBMP) that integrates flexible electronics for actively controlled transdermal delivery. The FBMP incorporates a flexible printed circuit board (FPCB), a eutectic gallium-indium (EGaIn) heating film, and dual-layer microneedles with a polyvinyl alcohol (PVA) core and polycaprolactone (PCL) shell. This configuration allows real-time adjustment of the thermal response rate via smartphone-controlled Bluetooth, achieving rapid drug release within 2 min or sustained release over 10 h. In various animal models, the FBMP demonstrate versatility in delivering multiple drug types, optimizing efficacy, and minimizing side effects for both acute and chronic conditions. Overall, this work introduces a flexible, universal electronic microneedle platform with significant potential to advance precision and personalized medicine by enabling customizable, actively controlled drug release.

Photosynthesis-Inspired NIR-Triggered Fe₃O₄@MoS₂ Core-Shell Nanozyme for Promoting MRSA-Infected Diabetic Wound Healing

Bacterial infections can lead to severe medical complications, including major medical incidents and even death, posing a significant challenge in clinical trauma repair. Consequently, the development of new, efficient, and non-resistant antimicrobial agents has become a priority for medical practitioners. In this study, a stepwise hydrothermal reaction strategy is utilized to prepare Fe3O4@MoS2 core-shell nanoparticles (NPs) with photosynthesis-like activity for the treatment of bacterial infections. The Fe3O4@MoS2 NPs continuously catalyze the production of reactive oxygen species (ROS) from hydrogen peroxide through photosynthesis-like reactions and convert light energy into heat with a photothermal efficiency of 30.30%. In addition, the photosynthetically generated ROS, combined with the iron-induced cell death mechanism of the Fe3O4@MoS2 NPs, confer them with exceptional and broad-spectrum antibacterial properties, achieving antimicrobial activities of up to 98.62% for Staphylococcus aureus, 99.22% for Escherichia coli, and 98.55% for methicillin-resistant Staphylococcus aureus. The composite exhibits good cell safety and hemocompatibility. Finally, a full-thickness diabetic wound model validates the significant pro-healing properties of Fe3O4@MoS2 in chronic diabetic wounds. Overall, the design of photosynthesis-inspired Fe3O4@MoS2 presents new perspectives for developing efficient photothermal nano-enzymatic compounds, offering a promising solution to the challenges of antimicrobial drug resistance and antibiotic misuse.

Functional-hydrogel-based electronic-skin patch for accelerated healing and monitoring of skin wounds

Conductive hydrogels feature reasonable electrical performance as well as tissue-like mechanical softness, thus positioning them as promising material candidates for soft bio-integrated electronics. Despite recent advances in materials and their processing technologies, however, facile patterning and monolithic integration of functional hydrogels (e.g., conductive, low-impedance, adhesive, and insulative hydrogels) for all-hydrogel-based soft bioelectronics still poses significant challenges. Here, we report material design, fabrication, and integration strategies for an electronic-skin (e-skin) patch based on functional hydrogels. The e-skin patch was fabricated by using photolithography-compatible functional hydrogels, such as poly(2-hydroxyethyl acrylate) (PHEA) hydrogel (substrate), Ag flake hydrogel (interconnection; conductivity: ∼571.43 S/cm), poly(3,4-ethylenedioxythiophene:polystyrene) (PEDOT:PSS) hydrogel (working electrode; impedance: ∼69.84 Ω @ 1 Hz), polydopamine (PDA) hydrogel (tissue adhesive; shear strength: ∼725.1 kPa), and poly(vinyl alcohol) (PVA) hydrogel (encapsulation). The properties of these functional hydrogels closely resemble those of human tissues in terms of water content and Young's modulus, enabling stable tissue-device interfacing in dynamically changing physiological environments. We demonstrated the efficacy of the e-skin patch through its application to accelerated healing and monitoring of skin wounds in mouse models - efficient fibroblast migration, proliferation, and differentiation promoted by electric field (EF) stimulation and iontophoretic drug delivery, and monitoring of the accelerated healing process through impedance mapping. The all-hydrogel-based e-skin patch is expected to create new opportunities for various clinically-relevant tissue interfacing applications.

Advances in wearable electronics for monitoring human organs: Bridging external and internal health assessments

Devices used for diagnosing disease are often large, expensive, and require operation by trained professionals, which can result in delayed diagnosis and missed opportunities for timely treatment. However, wearable devices are being recognized as a new approach to overcoming these difficulties, as they are small, affordable, and easy to use. Recent advancements in wearable technology have made monitoring information possible from the surface of organs like the skin and eyes, enabling accurate diagnosis of the user's internal status. In this review, we categorize the body's organs into external (e.g., eyes, oral cavity, neck, and skin) and internal (e.g., heart, brain, lung, stomach, and bladder) organ systems and introduce recent developments in the materials and designs of wearable electronics, including electrochemical and electrophysiological sensors applied to each organ system. Further, we explore recent innovations in wearable electronics for monitoring of deep internal organs, such as the heart, brain, and nervous system, using ultrasound, electrical impedance tomography, and temporal interference stimulation. The review also addresses the current challenges in wearable technology and explores future directions to enhance the effectiveness and applicability of these devices in medical diagnostics. This paper establishes a framework for correlating the design and functionality of wearable electronics with the physiological characteristics and requirements of various organ systems.

Harnessing Nature's ingenuity to engineer butterfly-wing-inspired photoactive nanofiber patches for advanced postoperative tumor treatment

Postoperative tumor treatment necessitates a delicate balance between eliminating residual tumor cells and promoting surgical wound healing. Addressing this challenge, we harness the innovation and elegance of nature's ingenuity to develop a butterfly-wing-inspired photoactive nanofiber patch (WingPatch), aimed at advancing postoperative care. WingPatch is fabricated using a sophisticated combination of electrostatic spinning and spraying techniques, incorporating black rice powder (BRP) and konjac glucomannan (KGM) into a corn-derived polylactic acid (PLA) nanofiber matrix. This fabrication process yields a paclitaxel-infused porous nanofiber architecture that mirrors the delicate patterns of butterfly wings. Meanwhile, all-natural composites have been selected for their strategic roles in postoperative recovery. BRP offers the dual benefits of photothermal therapy and antibacterial properties, while KGM enhances both antibacterial effectiveness and tissue regeneration. Responsive to near-infrared light, WingPatch ensures robust tissue adhesion and initiates combined photothermal and chemotherapeutic actions to effectively destroy residual tumor cells. Crucially, it simultaneously prevents infections and promotes wound healing throughout the treatment process. Its effectiveness has been confirmed by animal studies, and WingPatch significantly improves treatment outcomes in both breast and liver tumor models. Thus, WingPatch exemplifies our dedication to leveraging natural world's intricate patterns and inventiveness to propel postoperative care forward.

A review of sodium alginate-based hydrogels: Structure, mechanisms, applications, and perspectives

With the global emphasis on green and sustainable development, sodium alginate-based hydrogels (SAHs), as a renewable and biocompatible environmental material, have garnered widespread attention for their research and application. This review summarizes the latest advancements in the study of SAHs, thoroughly discussing their structural characteristics, formation mechanisms, and current applications in various fields, as well as prospects for future development. Initially, the chemical structure of SA and the network structure of hydrogels are introduced, and the impact of factors such as molecular weight, crosslinking density, and environmental conditions on the hydrogel structure is explored. Subsequently, the formation mechanisms of SAHs, including physical and chemical crosslinking, are detailed. Furthermore, a systematic review of the applications of SAHs in tissue engineering, drug delivery, medical dressings, wastewater treatment, strain sensor, and food science is provided. Finally, future research directions for SAHs are outlined. This work not only offers researchers a comprehensive framework for the study of SAHs but also provides significant theoretical and experimental foundations for the development of new hydrogel materials.

Biosensors integrated within wearable devices for monitoring chronic wound status

Slowly healing wounds significantly affect the life quality of patients in different ways, due to constant pain, unpleasant odor, reduced mobility up to social isolation, and personal frustration. While remote wound management has become more widely accepted since the COVID-19 pandemic, delayed treatment remains frequent and results in several wound healing related complications. As inappropriate management of notably diabetic foot ulcers is linked to a high risk of amputation, effective management of wounds in a patient-centered manner remains important to be implemented. The integration of diagnostic devices into wound bandages is under way, owing to advancements in materials science and nanofabrication strategies as well as innovation in communication technologies together with machine learning and data-driven assessment tools. Leveraging advanced analytical approaches around local pH, temperature, pressure, and wound biomarker sensing is expected to facilitate adequate wound treatment. The state-of-the-art of time-resolved monitoring of the wound status by quantifying key physiological parameters as well as wound biomarkers' concentration is presented herewith. A special focus will be given to smart bandages with on-demand delivery capabilities for improved wound management.

Network design for soft materials: addressing elasticity and fracture resistance challenges

Soft materials, such as elastomers and gels, feature crosslinked polymer chains that provide stretchable and elastic mechanical properties. These properties are derived from entropic elasticity, which limits energy dissipation and makes the material susceptible to fracture. To address this issue, network designs that dissipate energy through the plastic zone have been introduced to enhance toughness; however, this approach compromises elasticity, preventing the material from fully recovering its original shape after deformation. In this review, we describe the trade-off between fracture resistance and elasticity, exploring network designs that overcome this limitation to achieve both high toughness and low hysteresis. The development of soft materials that are both elastic and fracture-resistant holds significant promise for applications in stretchable electronics, soft robotics, and biomedical devices. By analyzing successful network designs, we identify strategies to further improve these materials and discuss potential enhancements based on existing limitations.

Toward Stretchable Flexible Integrated Sensor Systems

Skin-like flexible sensors hold great potential as the next generation of intelligent electronic devices owing to their broad applications in environmental monitoring, human-machine interfaces, the Internet of Things, and artificial intelligence. Flexible electronics inspired by human skin play a vital role in continuous and real-time health monitoring. This review summarizes recent progress in skin-mountable electronics developed by designing flexible electrodes and substrates into different structures, including serpentine, microcrack, wrinkle, and kirigami. Furthermore, this review briefly discusses advances in wearable integrated sensor systems that mimic the flexibility of human skin, as well as multisensing functions. In the future, innovations in stretchable integrated sensor systems will be crucial to develop next-generation intelligent skin-based sensors for practical applications such as medical diagnosis, treatment, and environment monitoring.

Advances in Wearable Biosensors for Wound Healing and Infection Monitoring

Wound healing is a complicated biological process that is important for restoring tissue integrity and function after injury. Infection, usually due to bacterial colonization, significantly complicates this process by hindering the course of healing and enhancing the chances of systemic complications. Recent advances in wearable biosensors have transformed wound care by making real-time monitoring of biomarkers such as pH, temperature, moisture, and infection-related metabolites like trimethylamine and uric acid. This review focuses on recent advances in biosensor technologies designed for wound management. Novel sensor architectures, such as flexible and stretchable electronics, colorimetric patches, and electrochemical platforms, enable the non-invasive detection of changes associated with wounds with high specificity and sensitivity. These are increasingly combined with AI and analytics based on smartphones that can enable timely and personalized interventions. Examples are the PETAL patch sensor that applies multiple sensing mechanisms for wide-ranging views on wound status and closed-loop systems that connect biosensors to therapeutic devices to automate infection control. Additionally, self-powered biosensors that tap into body heat or energy from the biofluids themselves avoid any external batteries and are thus more effective in field use or with limited resources. Internet of Things connectivity allows further support for remote sharing and monitoring of data, thus supporting telemedicine applications. Although wearable biosensors have developed relatively rapidly and their prospects continue to expand, regular clinical application is stalled by significant challenges such as regulatory, cost, patient compliance, and technical problems related to sensor accuracy, biofouling, and power, among others, that need to be addressed by innovative solutions. The goal of this review is to synthesize current trends, challenges, and future directions in wound healing and infection monitoring, with emphasis on the potential for wearable biosensors to improve patient outcomes and reduce healthcare burdens. These innovations are leading the way toward next-generation wound care by bridging advanced materials science, biotechnology, and digital health.

Smartphone administered pulsed radio frequency energy therapy for expedited cutaneous wound healing

Pulsed radio frequency energy (PRFE) therapy is a non-invasive, electromagnetic field-based treatment modality successfully used in clinical applications. However, conventional PRFE devices are often bulky, expensive, and require extended treatment durations, limiting patient adherence and efficacy. Here, we present a lightweight, cost-effective wearable PRFE system consisting of a flexible electronic bandage and a smartphone. The bandage, mainly composed of an NFC Frequency Doubler (NFD) and a Radiofrequency Energy Radiator (RER), is powered and administered by the smartphone to generate 27.12 MHz radio wave pulses, for simplified, smartphone-enabled PRFE therapy. Its ultra-flexible, battery-free design supports personalized wound care at a low-cost ( Collapse

Key Words

• therapeutics
• biomedical engineering

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MESH Headings Collapse

Grants

• Shenzhen Science and Technology Innovation Commission
• Shenzhen Science and Technology Program (20210331163905001), High Level of Special Funds (G03034K002).

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Affiliation(s)

Mengxia Yu Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
Hongjia Yang Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China School of Biomedical Engineering, Tsinghua University, Beijing, China
Haoteng Ye Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
Shuhuang Lin School of Medicine, Southern University of Science and Technology, Shenzhen, China
Yujie Lu Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
Haoqiang Deng Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
Lulu Xu The Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, UK
Yongxin Guo Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China.
John S Ho Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore. The N.1 Institute for Health, National University of Singapore, Singapore, Singapore. Institute for Health Innovation and Technology, National University of Singapore, Singapore, Singapore.
Terry Tao Ye Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China. Institute of Nanoscience and Applications, Southern University of Science and Technology, Shenzhen, China.

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Advancements in Wound Dressing Materials: Highlighting Recent Progress in Hydrogels, Foams, and Antimicrobial Dressings

Recent advancements in wound dressing materials have significantly improved acute and chronic wound management by addressing challenges such as infection control, moisture balance, and enhanced healing. Important progress has been made, especially with hydrogels, foams, and antimicrobial materials for creating optimized dressings. Hydrogels are known for maintaining optimal moisture levels, while foam dressings are excellent exudate absorbents. Meanwhile, antimicrobial dressing incorporates various antimicrobial agents to reduce infection risks. These dressing options reduce wound healing time while focusing on customized patient needs. Therefore, this review highlights the newest research materials and prototypes for wound healing applications, emphasizing their particular benefits and clinical importance. Innovations such as stimuli-responsive hydrogels and hybrid bioengineered composites are discussed in relation to their enhanced properties, including responsiveness to pH, temperature, glucose, or enzymes and drug delivery precision. Moreover, ongoing clinical trials have been included, demonstrating the potential of emerging solutions to be soon translated from the laboratory to clinical settings. By discussing interdisciplinary approaches that integrate advanced materials, nanotechnology, and biological insights, this work provides a contemporary framework for patient-centric, efficient wound care strategies.

A bio-inspired microwave wireless system for constituting passive and maintenance-free IoT networks

With the rapid expansion of wireless networks, the deployment and long-term maintenance of distributed microwave terminals have become increasingly challenging. To address these issues, we present a bio-inspired microwave system to constitute passive and maintenance-free wireless networks. Drawing inspiration from vertebrate skeletons and skins, we employ stimuli-responsive polymer with tunable stiffness to support and protect sensitive electromagnetic structures, and synthesize self-healable skin-like polymer for system encapsulation. Owing to the biomimetic strategy, our system combines outstanding flexibility, electromagnetic stability, structural robustness, and self-healable performance. On the other hand, to address power supply issues, our system modulates ambient electromagnetic waves to achieve long-range wireless communication, and the hybrid energy harvesting strategy allows the system to capture energy from ambient light and microwaves, thereby eliminating the need for batteries or power cables. Multidisciplinary innovation enables our system to be deployed almost anywhere and supports stable, battery-less, and maintenance-free wireless communication.

A Smart Semi-Implantable Device Integrating Microchannel-Enhanced Sampling and Multiplex Biochemical Testing for Deep Wound Monitoring and Pathogen Identification

Monitoring deep wounds is challenging but necessary for high-quality medical treatment. Current methodologies for deep wound monitoring are typically limited to indirect clinical symptoms or costly non-real-time imaging diagnosis. Herein, a smart system is proposed that enables in situ monitoring of deep wounds' status through a semi-implantable device composed of 2 seamlessly connected functional components: 1) the well-designed, microchannel-structured sampling needles that efficiently and conveniently collect samples from deep wound anatomical locations, and 2) the multiplex biochemical testing compartment that facilitates the immediate and persistent detection of multiple biochemical indicators based on a color image processing software accessible to a conventional smartphone. With the 3 representative preclinical deep wound models, the study demonstrates the device's potential to monitor wound infection, inflammation, healing progress, and reduce inflammation when applied to deep skin injury, surgical implantation, and postoperative intestinal leakage. The device's capability to rapidly and accurately identify pathogenic bacteria is also demonstrated both in vitro and in vivo, potentially facilitating precise intervention in infected wounds. Coupled with the device's favorable biocompatibility and cost-effectiveness, this intelligent system emerges as a promising tool for safe and effective management of complicated deep wounds.

Platelet extracellular vesicles-loaded hydrogel bandages for personalized wound care

Autologous or allogeneic platelet-derived extracellular vesicles (pEVs) show potential in enhancing tissue recovery and healing chronic wounds. pEVs promote neovascularization and cell migration while reducing inflammation, oxidative stress, and scarring. However, their efficacy in clinical settings is challenged by their susceptibility to washout by wound exudate. Hydrogel-based bandages are effective carriers that stabilize pEVs for optimal personalized wound care. These bandages can be tailored for easy removal to minimize damage to regenerated tissue and can incorporate antibacterial or moisture-retaining properties. Furthermore, the possibility of integrating sensors in the wound bed will enable a theragnostic approach to healing. This review explores advancements in pEV-loaded hydrogels and their potential for personalized clinical applications.

Multifunctional Adhesive Hydrogels: From Design to Biomedical Applications

Adhesive hydrogels characterized by structural properties similar to the extracellular matrix, excellent biocompatibility, controlled degradation, and tunable mechanical properties have demonstrated significant potential in biomedical applications, including tissue engineering, biosensors, and drug delivery systems. These hydrogels exhibit remarkable adhesion to target substrates and can be rationally engineered to meet specific requirements. In recent decades, adhesive hydrogels have experienced significant advancements driven by the introduction of numerous multifunctional design strategies. This review initially summarizes the chemical bond-based design strategies for tissue adhesion, encompassing static covalent bonds, dynamic covalent bonds, and non-covalent interactions. Subsequently, the multiple functionalities imparted by these diverse design strategies, including highly stretchable and tough performances, responsiveness to microenvironments, anti-freezing/heating properties, conductivity, antibacterial activity, and hemostatic properties are discussed. In addition, recent advances in the biomedical applications of adhesive hydrogels, focusing on tissue repair, drug delivery, medical devices, and wearable sensors are reviewed. Finally, the current challenges are highlighted and future trends in this rapidly evolving field are discussed.

Multifunctional Porous Soft Bioelectronics

Soft bioelectronics, seamlessly interfacing with the human body to enable both recording and modulation of curvilinear biological tissues and organs, have significantly driven fields such as digital healthcare, human-machine interfaces, and robotics. Nonetheless, intractable challenges persist due to the onerous demand for imperceptible, burden-free, and user-centric comfortable bioelectronics. Porous soft bioelectronics is a new way to a library of imperceptible bioelectronic systems, that form natural interfaces with the human body. In this review, we provide an overview of the development and recent advances in multifunctional porous engineered soft bioelectronics, aiming to bridge the gap between living biotic and stiff abiotic systems. We first discuss strategies for fabricating porous, soft, and stretchable bioelectronic materials, emphasizing the concept of materials-level porous engineering for breathable and imperceptible bioelectronics. Next, we summarize wearable bioelectronics devices and multimodal systems with porous configurations designed for on-skin healthcare applications. Moving beneath the skin, we discuss implantable devices and systems enabled by porous bioelectronics with tissue-like compliance. Finally, existing challenges and translational gaps are also proposed to usher further research efforts towards realizing practical and clinical applications of porous bioelectronic systems; thus, revolutionizing conventional healthcare and medical practices and opening up unprecedented opportunities for long-term, imperceptible, non-invasive, and human-centric healthcare networks.

A skin-mountable flexible biosensor based on Cu-MOF/PEDOT composites for sweat ascorbic acid monitoring

Continuous monitoring of sweat nutrients offers valuable insights into metabolic cycling and health levels. However, existing methods often lack adaptability and real-time capabilities. Here, we propose a skin-mountable flexible biosensor integrated with metal-organic framework (MOF)-derived composites for real-time monitoring of sweat ascorbic acid (AA) levels. The biosensor features a miniaturized, highly integrated system capable of an imperceptible, stretchable skin patch with dimensions of 16.9 × 9.9 × 0.1 mm3, ensuring conformal integration with curvilinear skin contours. The introduction of a copper-based MOF anchored with poly(3,4-ethylenedioxythiophene) (Cu-MOF/PEDOT) significantly enhances sensing performance toward AA, achieving a detection limit of 0.76 μM and a sensitivity of 725.7 μA/(mM·cm2). Moreover, a miniaturized flexible circuit enables wireless communication, resulting in a lightweight, wearable platform weighing only 1.3 g. Structural and electrochemical analyses confirm the favorable sensitivity, reversibility, and stability of the biosensor, while in-vivo validation in human subjects further reveals the capability to track sweat AA variations during nutrient intake and sustained exercise, showcasing its potential in metabolic cycle assessment and health management. The biosensor presents a promising avenue for scalable health monitoring using adaptable and user-friendly technologies.

Engineering Steep Subthreshold Swings in High-Performance Organic Field-Effect Transistor Sensors

Organic field-effect transistor (OFET)-based sensors have gained considerable attention for information perception and processing in developing artificial intelligent systems owing to their amplification function and multiterminal regulation. Over the last few decades, extensive research has been conducted on developing OFETs with steep subthreshold swings (SS) to achieve high-performance sensing. In this review, based on an analysis of the critical factors that are unfavorable for a steep SS in OFETs, the corresponding representative strategies for achieving steep SS are summarized, and the advantages and limitations of these strategies are comprehensively discussed. Furthermore, a bridge between SS and OFET sensor performance is established. Subsequently, the applications of OFETs with steep SS in sensor systems, including pressure sensors, photosensors, biochemical sensors, and electrophysiological signal sensors. Lastly, the challenges faced in developing OFET sensors with steep SS are discussed. This study provides insights into the design and application of high-performance OFET sensor systems.

Chronic wound management: a liquid diode-based smart bandage with ultrasensitive pH sensing ability

Chronic wounds, which require prolonged healing periods, pose significant impacts on individuals with diabetes, vascular diseases, and high blood pressure. Simultaneous drainage and monitoring of wound exudate are vital for advanced wound management. However, recently reported smart dressings either lack integration of wound cleaning and monitoring functions or fail to achieve dynamic in situ monitoring of wound status, which hinders their ability to meet the demands of wound care. In this study, a smart bandage is introduced, which integrates a biocompatible liquid diode membrane with an ultrasensitive 3D polyaniline mesh (M-PANI)-based pH biosensor. The smart bandage allows for unidirectional drainage of wound exudate while dynamically sensing the wound pH environment. Specifically, the proposed smart bandage effectively cleans excessive wound exudate while providing real-time information on the wound status during the drainage process. The M-PANI-based pH biosensor demonstrates a high sensitivity of 61.5 mV/pH and a wide pH detection range from 4.0 to 10.0, encompassing the pH range of normal and infected wounds. Moreover, the sensing module exhibits excellent stability after 48 hours of dynamic testing and 28 days of storage, with only a 4.8% decline in the detected signal, and high repeatability with a device-to-device relative standard deviation (RSD) of 3.1%. To evaluate the practicality of this smart bandage, simulated skin and rats have been employed, and the results indicate the immense potential of this smart bandage for clinical applications. In conclusion, the present smart bandage demonstrates considerable promise for wound exudate cleaning and monitoring in advanced wound care and offers a promising method for home-based wound management.

Electrical Stimulation Therapy - Dedicated to the Perfect Plastic Repair

Tissue repair and reconstruction are a clinical difficulty. Bioelectricity has been identified as a critical factor in supporting tissue and cell viability during the repair process, presenting substantial potential for clinical application. This review delves into various sources of electrical stimulation and identifies appropriate electrode materials for clinical use. It also highlights the biological mechanisms of electrical stimulation at both the subcellular and cellular levels, elucidating how these interactions facilitate the repair and regeneration processes across different organs. Moreover, specific electrode materials and stimulation sources are outlined, detailing their impact on cellular activity. The future development trends are projected from two perspectives: the optimization of equipment performance and the fulfillment of clinical demands, focusing on the feasibility, safety, and cost-effectiveness of technologies.

Liquid Metal-Enabled Epidermal Interfaces

Soft materials are crucial for epidermal interfaces in biomedical devices due to their capability to conform to the body compared to rigid inorganic materials. Gels, liquids, and polymers have been extensively explored, but they lack sufficient electrical and thermal conductivity required for many application settings. Gallium-based alloys are molten metals at room temperature with exceptional electrical and thermal conductivity. These liquid metals and their composites can be directly applied onto the skin as interface materials. In this Spotlight on Applications, we focus on the rapidly evolving field of liquid metal-enabled epidermal interfaces featuring unique physical properties beyond traditional gels and polymers. We delve into the role of liquid metal in electrical and thermal biointerfaces in various epidermal applications. Current challenges and future directions in this active area are also discussed.

Low Voltage-Enhanced Mechano-Bactericidal Biopatch

Mechano-bactericidal strategies represent a safe and sustainable method for preventing microbial contamination in the postantibiotic era. However, their effectiveness against Gram-positive bacteria (≤55%) is still limited due to the thick peptidoglycan layer in their cell walls. Herein, an intelligent biomimetic nanopillared biopatch is developed. It is assisted by low-voltage (8 V) electrical stimulation from TENG and significantly enhances antibacterial efficacy (>99%) against three types of stubborn Gram-positive bacteria. These collaborative antibacterial behaviors are solely based on purely physical actions, thus avoiding the risk of triggering bacterial resistance. Moreover, the slight mechanical energy generated by human physiological activities is converted into a power source, exhibiting energy-efficient, eco-friendly, and sustainable features. The conductive hydrogel in the biopatch can also act as an intelligent temperature sensor, monitoring, and real-time assessment of wound conditions. This intelligent biopatch holds immense potential for efficient healing and safe management of both acute and chronic wound infections.

Customized surface adhesive and wettability properties of conformal electronic devices

Conformal and body-adaptive electronics have revolutionized the way we interact with technology, ushering in a new era of wearable devices that can seamlessly integrate with our daily lives. However, the inherent mismatch between artificially synthesized materials and biological tissues (caused by irregular skin fold, skin hair, sweat, and skin grease) needs to be addressed, which can be realized using body-adaptive electronics by rational design of their surface adhesive and wettability properties. Over the past few decades, various approaches have been developed to enhance the conformability and adaptability of bioelectronics by (i) increasing flexibility and reducing device thickness, (ii) improving the adhesion and wettability between bioelectronics and biological interfaces, and (iii) refining the integration process with biological systems. Successful development of a conformal and body-adaptive electronic device requires comprehensive consideration of all three aspects. This review starts with the design strategies of conformal electronics with different surface adhesive and wettability properties. A series of conformal and body-adaptive electronics used in the human body under both dry and wet conditions are systematically discussed. Finally, the current challenges and critical perspectives are summarized, focusing on promising directions such as telemedicine, mobile health, point-of-care diagnostics, and human-machine interface applications.

Flexible bioelectronic systems with large-scale temperature sensor arrays for monitoring and treatments of localized wound inflammation

Continuous monitoring and closed-loop therapy of soft wound tissues is of particular interest in biomedical research and clinical practices. An important focus is on the development of implantable bioelectronics that can measure time-dependent temperature distribution related to localized inflammation over large areas of wound and offer in situ treatment. Existing approaches such as thermometers/thermocouples provide limited spatial resolution, inapplicable to a wearable/implantable format. Here, we report a conformal, scalable device package that integrates a flexible amorphous silicon-based temperature sensor array and drug-loaded hydrogel for the healing process. This system can enable the spatial temperature mapping at submillimeter resolution and high sensitivity of 0.1 °C, for dynamically localizing the inflammation regions associated with temperature change, automatically followed with heat-triggered drug delivery from hydrogel triggered by wearable infrared light-emitting-diodes. We establish the operational principles experimentally and computationally and evaluate system functionalities with a wide range of targets including live animal models and human subjects. As an example of medical utility, this system can yield closed-loop monitoring/treatments by tracking of temperature distribution over wound areas of live rats, in designs that can be integrated with automated wireless control. These findings create broad utilities of these platforms for clinical diagnosis and advanced therapy for wound healthcare.