Reshaping the Endogenous Electric Field to Boost Wound Repair via Electrogenerative Dressing

Force-electric biomaterials and devices for regenerative medicine

There is a growing recognition that force-electric conversion biomaterials and devices can convert mechanical energy into electrical energy without an external power source, thus potentially revolutionizing the use of electrical stimulation in the biomedical field. Based on this, this review explores the application of force-electric biomaterials and devices in the field of regenerative medicine. The article focuses on piezoelectric biomaterials, piezoelectric devices and triboelectric devices, detailing their categorization, mechanisms of electrical generation and methods of improving electrical output performance. Subsequently, different sources of driving force for electroactive biomaterials and devices are explored. Finally, the biological applications of force-electric biomaterials and devices in regenerative medicine are presented, including tissue regeneration, functional modulation of organisms, and electrical stimulation therapy. The aim of this review is to emphasize the role of electrical stimulation generated by force-electric conversion biomaterials and devices on the regulation of bioactive molecules, ion channels and information transfer in living systems, and thus affects the metabolic processes of organisms. In the future, physiological modulation of electrical stimulation based on force-electric conversion is expected to bring important scientific advances in the field of regenerative medicine.

A carbon nanotube/pyrrolidonecarboxylic acid zinc sponge for programmed management of diabetic wounds: Hemostatic, antibacterial, anti-inflammatory, and healing properties

Wound healing in patients with diabetes is challenging because of chronic inflammation, inadequate vascularization, and susceptibility to infection. Current wound dressings often target specific stages of healing and lack comprehensive therapeutic approaches. This study introduces a novel approach using a photodetachable sponge scaffold incorporating carbon nanotubes (CNTs), known for their high photothermal conversion efficiency, electrical conductivity, and water absorption properties. The scaffold incorporated pyrrolidonecarboxylic acid zinc (PC1Z2), a compound with anti-inflammatory and moisturizing properties, which was cross-linked within a network of CNTs and a decellularized dermal matrix. The resulting shape-memory sponge scaffold actively interfaces with endogenous electric fields, facilitating electrical signal transmission to skin cells and accelerating tissue repair. Upon exposure to near-infrared (NIR) light, the PC1Z2 scaffold enhanced antibacterial efficacy (98 %) through photothermal conversion, promoting tissue metabolism at the wound site. Notably, the scaffold absorbed wound exudates and gradually released Zn2+, effectively reducing chronic inflammation in the mice. In a diabetic rat wound model, the PC1Z2 scaffold absorbed exudates, reduced inflammation, and accelerated granulation tissue formation, wound angiogenesis, and re-epithelialization. This innovative PC1Z2 sponge dressing shows promise for enhancing the healing of diabetic wounds.

Innovative Self-Powered Electrically Stimulated Fabric Dressing for Enhanced Diabetic Wound Healing

Electrical stimulation (ES) therapy has emerged as a promising method for improving wound healing by mimicking the body's natural electric fields. However, traditional ES devices often fall short in practical applications due to their bulkiness and inefficiency. Current tools for electrical stimulation are hindered by issues such as poor sustainability, limited flexibility, and inadequate biocompatibility. To address these challenges, we have developed a novel self-powered electrical stimulation fabric dressing (SESFD). This innovative dressing employs advanced electrochemical deposition technology to integrate fiber electrodes seamlessly into the fabric using standard textile manufacturing methods. Additionally, we incorporated a gel electrolyte infused with antimicrobial agents to enhance protection against bacterial infections during electrical stimulation. To evaluate the effectiveness of the SESFD in promoting healing for chronic diabetic wounds, we conducted rigorous in vivo studies. The results demonstrated that the SESFD significantly improved cell proliferation and migration within the wound tissue while effectively reducing bacterial growth. These enhancements contributed to faster wound closure, decreased inflammatory response, increased collagen deposition, and improved angiogenesis. Furthermore, the SESFD displayed excellent mechanical properties, extended discharge durability, and stable voltage output even under mechanical deformation. These attributes greatly enhance user experience and comfort for patients throughout the healing process. This study positions the SESFD as a groundbreaking solution that combines electrical stimulation with antimicrobial treatment for diabetic wound care. It represents a sustainable, flexible, and biocompatible approach to accelerating wound healing and improving treatment outcomes.

3D-printed kirigami-inspired asymmetric dressings: custom elasticity and self-pumping for enhanced wound healing

Preventing infections and managing excessive exudate in dynamic joints are vital for effective wound treatment. Accurately fitting dressings to wound shapes remains a significant challenge, which can adversely affect both healing and patient comfort. This study introduces a self-pumping dressing with a tailored shape and tensile properties. This dressing channels excessive wound fluid in a unidirectional manner achieved by electrospinning hydrophobic nanofibers embedded with silver nanoparticles (AgNPs) onto a hydrophilic 3D-printed patch featuring a kirigami structure. By systematically adjusting the parameter-cutting length l, horizontal spacing d, and vertical spacing h, we enabled the elongation of the 3D-printed patch to range from 26% to 244%. Our personalized self-pumping dressings demonstrated effective antibacterial activity, unidirectional fluid transmission, and biocompatibility, thereby accelerating wound healing. This research establishes a promising pathway for personalized and precise local wound care.

Electroactive Electrospun Nanofibrous Scaffolds: Innovative Approaches for Improved Skin Wound Healing

The incidence and burden of skin wounds, especially chronic and complex wounds, have a profound impact on healthcare. Effective wound healing strategies require a multidisciplinary approach, and advances in materials science and bioengineering have paved the way for the development of novel wound healing dressing. In this context, electrospun nanofibers can mimic the architecture of the natural extracellular matrix and provide new opportunities for wound healing. Inspired by the bioelectric phenomena in the human body, electrospun nanofibrous scaffolds with electroactive characteristics are gaining widespread attention and gradually emerging. To this end, this review first summarizes the basic process of wound healing, the causes of chronic wounds, and the current status of clinical treatment, highlighting the urgency and importance of wound dressings. Then, the biological effects of electric fields, the preparation materials, and manufacturing techniques of electroactive electrospun nanofibrous (EEN) scaffolds are discussed. The latest progress of EEN scaffolds in enhancing skin wound healing is systematically reviewed, mainly including treatment and monitoring. Finally, the importance of EEN scaffold strategies to enhance wound healing is emphasized, and the challenges and prospects of EEN scaffolds are summarized.

Endogenous electric field-driven neuro-immuno-regulatory scaffold for effective diabetic wound healing

The pathological microenvironment in diabetic wounds is delineated by heightened inflammatory responses and persistent proinflammatory macrophage activity, which significantly hinders the wound healing process. Exogenous electrical stimulation (ES), by modulating the electric field distribution in wounds, has shown significant potential in treating inflammatory wounds. However, this approach relies on additional power sources and complex circuit designs. Here, a bionic neuro-immuno-regulatory (BNIR) system was proposed for reshaping the endogenous electric fields (EFs) through collecting ion flow. The BNIR system comprises microporous structure scaffolds and nanosheets, enabling swift biofluid collection and electrical signal transmission, with the ability to promote cell proliferation and migration and exhibit antioxidant properties. More importantly, the BNIR system induced the transition of M1 macrophages to M2 macrophages through neuro-immuno-regulatory. In diabetic rat skin wounds, the BNIR system significantly enhanced healing by simultaneously neuro-immuno-regulatory, promoting angiogenesis, scavenging ROS, and facilitating tissue remodeling. This work aims to advance the development of a bionic system for electrosensitive tissue repair.

Electro- and Magneto-Active Biomaterials for Diabetic Tissue Repair: Advantages and Applications

The diabetic tissue repair process is frequently hindered by persistent inflammation, infection risks, and a compromised tissue microenvironment, which lead to delayed wound healing and significantly impact the quality of life for diabetic patients. Electromagnetic biomaterials offer a promising solution by enabling the intelligent detection of diabetic wounds through electric and magnetic effects, while simultaneously improving the pathological microenvironment by reducing oxidative stress, modulating immune responses, and exhibiting antibacterial action. Additionally, these materials inherently promote tissue regeneration by regulating cellular behavior and facilitating vascular and neural repair. Compared to traditional biomaterials, electromagnetic biomaterials provide advantages such as noninvasiveness, deep tissue penetration, intelligent responsiveness, and multi-stimuli synergy, demonstrating significant potential to overcome the challenges of diabetic tissue repair. This review comprehensively examines the superiority of electromagnetic biomaterials in diabetic tissue repair, elucidates the underlying biological mechanisms, and discusses specific design strategies and applications tailored to the pathological characteristics of diabetic wounds, with a focus on skin wound healing and bone defect repair. By addressing current limitations and pursuing multi-faceted strategies, electromagnetic biomaterials hold significant potential to improve clinical outcomes and enhance the quality of life for diabetic patients.

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.

A Heterojunction Piezoelectric Antimicrobial Asymmetric Hydrogel for Dynamic Wound Healing and Monitoring

Dynamic wound care presents significant challenges for conventional dressings due to the complex environment and high-frequency motion associated with such injuries. In this study, a multifunctional photo-crosslinked piezoelectric hydrogel (OAPS) is developed, incorporating heterojunction Se-doped KH570 modified BaTiO3 nanoparticles (Se-BT570 NPs) as a core component, and designed to address antimicrobial and monitoring needs in wound care, particularly at sites with high-frequency movement. The OAPS hydrogel effectively utilizes the inherent high-frequency motion in dynamic wounds, enhancing antimicrobial efficacy and enabling real-time monitoring of wound and human health statuses. This is achieved through the synergistic effects of piezoelectric properties and nano-heterostructures that enable self-driven charge transfer. Such integration allows for dual applications in both diagnosis and treatment. Experimental results demonstrated that the OAPS hydrogel exhibits excellent mechanical strength and adhesive properties, effectively adapting to high-frequency motion. Additionally, the hydrogel can be activated by dynamic wound environments to perform antimicrobial and wound monitoring functions, significantly accelerating the healing of dynamic wounds, with an efficacy rate of 99.75%. This study highlights the potential of piezoelectric nanomaterials in dynamic wound healing, offering a promising strategy for managing complex, dynamic wound care.

Flexible Patterned Fuel Cell Patches Stimulate Nerve and Myocardium Restoration

The distribution of electrical potentials and current in exogenous electrostimulation has significant impacts on its effectiveness in promoting tissue repair. However, there is still a lack of a flexible, implantable power source capable of generating customizable patterned electric fields for in situ electrostimulation(electrical stimulation). Herein, this study reports a fuel cell patch (FCP) that can provide in situ electrostimulation and a hypoxic microenvironment to promote tissue repair synergistically. Stable and highly efficient PtNi nanochains and PtNi nanocages electrocatalysts with anti-interference properties catalyze glucose oxidation and oxygen reduction respectively in an encapsulation-free fuel cell. The laser-induced graphene (LIG) electrode loaded with PtNi electrocatalysts is transferred to the surface of a flexible chitosan hydrogel. The resulting flexible FCP can adapt to tissues with different morphologies, firmly adhere to prevent suturing, and provide potent electrostimulation (0.403 V, 51.55 µW cm-2). Additionally, it consumes oxygen in situ to create a hypoxic microenvironment, increasing the expression of hypoxia-inducible factor-1α (HIF-1α). Based on the different pattern requirements of exogenous electrostimulation during the repair of various types of tissue, an axial FCP for peripheral nerves and a flower-patterned FCP for myocardial tissue are constructed and transplanted into animals, showing significant tissue repair in both models.

Dual-Action flavonol carbonized polymer dots spray: Accelerating burn wound recovery through immune responses modulation and EMT induction

Effective immune homeostasis modulation and re-epithelialization promotion are crucial for accelerating burn wound healing. Cell migration is fundamental to re-epithelialization, with epithelial-mesenchymal transition (EMT) as a key mechanism. A sustained inflammatory environment or impaired macrophage transition to M2 phenotype can hinder pro-resolving cytokine activation, further delaying the recruitment, migration, and re-epithelialization of epidermal cells to the injury site, ultimately compromising wound healing. Herein, the bioactive flavonol quercetin is transformed into pharmacologically active carbonized polymer dots (Qu-CDs) spray with high water dispersibility, permeability and biocompatibility for full-thickness skin burns treatment. Qu-CDs spray can efficiently initiate macrophage reprogramming and promote the transition of macrophages from M1 to M2 phenotype, modulating immune responses and facilitating the shift from the inflammatory phase to re-epithelialization. Additionally, Qu-CDs spray can promote cell migration and re-epithelialization of wound edge epithelial cells by inducing an EMT process without growth factors, further accelerating the reconstruction of the normal epidermal barrier. Mechanistically, Qu-CDs spray activates the smad1/5 signaling pathway for promoting the EMT phenotype of wound edge epithelial cells. Overall, this study facilitates the construction of novel spray dosage form of pharmacologically active carbonized polymer dots with desired bioactivities for effective wound healing.

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.

Conductive Hydrogel Inspires Neutrophil Extracellular Traps to Combat Bacterial Infections in Wounds

Thetreatment of infected wounds is currently a major challenge in clinical medicine, and enhancing antimicrobial and angiogenic capacity is one of the most common strategies. However, the current treatment makes it difficult to balance the antimicrobial effect in the early stage and the angiogenic effect in the later stages of wound healing, leading to an increased rate of poor prognosis. Here, we present a nanoconductive hydrogel EF@S-HGM, consisting of HGM with ECGS, FMLP, and SWCNT. The host-guest supramolecular macromolecule (HGM) hydrogel is biocompatible and can be injected in situ in the wound. The endothelial cell growth factor (ECGS) accelerates vascular remodeling and repairs wounds by promoting the proliferation of endothelial cells. N-Formyl-Met-Leu-Phe (FMLP) recruits neutrophils and increases the antimicrobial capacity. Single-walled carbon nanotubes (SWCNT) make the hydrogel conductive, enabling the hydrogel to utilize the endogenous electric field in the wound to recruit multiple kinds of cells. In addition, we found that the EF@S-HGM hydrogel activates the glucocorticoid receptor senescence pathway and promotes the formation of NET, which enhances the antimicrobial effect. As tissue-engineered skin, the conductive hydrogel EF@S-HGM is a promising material for regenerative medicine that may provide a potential option for the treatment and care of infected wounds and significantly improve patient outcomes and prognosis.

Electroactive Dressing with Selective Sorption of Exudate Enables Treatment of Complicated Wound

Exudate management and cell activity enhancement are vital to complicated wound healing. However, current exudate management dressings indiscriminately remove exudate, which is detrimental to cell activity enhancement. Herein, a novel class of electroactive bilayer (cMO/PVA) dressing is developed by constructing manganese oxide nanoneedle-clusters decorated commercial carbon cloth (MO), in situ casting polyvinyl alcohol (PVA) hydrogel, and finally charging. Benefitting from the hierarchical nanoneedle-cluster structure of MO, abundant active sites are sufficiently exposed to achieve high area-specific capacitances (e.g., 1881.3 mF cm-2), thereby establishing the long-lasting electric field for cMO/PVA dressing. Such a unique cMO/PVA dressing can realize extraordinary selective sorption toward noxious substances over nutrient substances during exudate management. Meanwhile, its long-term electrical stimulation therapy can promote cell proliferation and migration and enhance antibacterial property. As a result, our multifunctional cMO/PVA dressing can rapidly repair full-thickness wounds in type II diabetic rats, offering an advanced strategy for the treatment of complicated wounds.

Autonomous, Moisture-Driven Flexible Electrogenerative Dressing for Enhanced Wound Healing

Electrotherapy has shown considerable potential in treating chronic wounds, but conventional approaches relying on bulky external power supplies and mechanical force are limited in their clinical utility. This study introduces an autonomous, moisture-driven flexible electrogenerative dressing (AMFED) that overcomes these limitations. The AMFED integrates a moist-electric generator (MEG), an antibacterial hydrogel dressing, and concentric molybdenum (Mo) electrodes to provide a self-sustaining electrical supply and potent antibacterial activity against Staphylococcus aureus and Escherichia coli. The MEG harnesses chemical energy from moisture to produce a stable direct current of 0.61 V without external input, delivering this therapeutic electrical stimulation to the wound site through the Mo electrodes. The AMFED facilitates macrophage polarization toward reparative M2 phenotype and regulates inflammatory cytokines. Moreover, in vivo studies suggest that the AMFED group significantly enhances chronic wound healing, with an approximate 41% acceleration compared to the control group. Using a diabetic mouse wound model, the AMFED demonstrates its effectiveness in promoting nerve regulation, epithelial migration, and vasculogenesis. These findings present a novel and efficient platform for accelerating chronic wound healing.

Flexible and Robust Piezoelectric Chitosan Films with Enhanced Bioactivity

Chitosan (CHT) is a known piezoelectric biomacromolecule; however, its usage is limited due to rapid degradation in an aqueous system. Herein, we prepared CHT film via a solvent casting method and cross-linked in an alkaline solution. Sodium hydroxide facilitated deprotonation, leading to increased intramolecular hydrogen bonding and mechanical properties. The CHT film remained intact for 30 days in aqueous environments. A systematic study revealed a gradual increase in the output voltage from 0.9 to 1.8 V under external force (1-16 N). In addition, the CHT film showed remarkable antibacterial and anti-inflammatory activities under ultrasound stimulation and inhibition of inflammatory cytokines. The CHT films also displayed enhanced cellular proliferation and ∼5-fold faster migration of NIH3T3 cells under US stimulation. Overall, this work presents a robust, biocompatible, and wearable CHT device that can transform biomechanical energy into electrical pulses for the modulation of cell fate processes and other bioactivities.

Low-energy electric shock ameliorates cell proliferation, morphallaxis, and regeneration via driving key regenerative proteins in earthworm and 3T3 cells

Electric stimulation regulates many cellular processes like cell proliferation, differentiation, apoptosis and cellular migration. Despite its crucial role in regulating stem cells and regeneration, it remains underexplored in both in-vivo and in-vitro settings. In this study, Eudrilus eugeniae are subjected to electric stimulation (1.5 V) prior and after amputation and which augments regeneration up to double-time. Blocking epimorphosis using 2 M thymidine retracts regeneration kinetics to one-third but such inhibition was rescued by applying electric stimulation which propels an overactive morphallaxis pattern of regeneration. Excreting electric stimulation on control worms shows minimal impact, whereas it enhances the key regenerative proteins like VEGF, COX2, YAP, c-Myc, and Wnt3a on amputated worms. Upon blocking epimorphosis, all these key regenerative proteins are down-regulated but through electric stimulation, the cells are reprogrammed to express a triple fold of the mentioned regenerative proteins, that further promotes morphallaxis. In 3T3 cells, electric stimulation accelerates cell proliferation and migrations in 5 secs exposure and it exerts its function by overexpressing VEGF mediated by MEK1. Wnt3a expression was gradually upregulated in increasing exposure (5 and 25 secs) which aids in maintaining the stemness property. The molecular mechanism underlying regeneration capability can assist in designing novel therapeutic applications.

Electricallymodified bacterial cellulose tailored with plant based green materials for infected wound healing applications

Effective treatment of infected wounds remains a challenge due to the rise of antibiotic-resistant microorganisms. The development of advanced materials with strong antimicrobial properties is necessary to address this issue. In this study, a unique composite of electrically modified bacterial cellulose (EBC) with allantoin (ABC) and zein was developed by dipping diffusion method. Morphological structural analysis revealed a uniform distribution of zein and aligned fibers, confirming the synthesis of the ABC-Zein composite. The formation of ABC-Zein was further confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR), which displayed additional peaks corresponding to EBC, indicating the incorporation of zein into ABC. X-ray diffraction (XRD) analysis of ABC-Zein demonstrated a similar crystalline structure with EBC. The ABC-Zein showed mechanical integrity (tensile strength: 1.15 ± 0.21 MPa), thermal stability (degradation temperature: 290 °C), porous structure (porosity: 40.23 ± 0.21 %), and hydrophilic (water contact angle: 53.3 ± 5.3°) properties. Furthermore, the antimicrobial agent terpinen-4-ol (T4O), derived from tea tree oil, was incorporated into the ABC-Zein composite. Biological studies confirmed the antimicrobial efficacy (Staphylococcus aureus inhibition: 88.5 ± 7.19 %) and biocompatible (cell viability: 84.95 ± 5.6 %, hemolysis: 4.479 ± 0.39 %) nature of the T4O-ABC-Zein composite. The combined effects of the aligned fiber structure, zein protein, and antimicrobial T4O significantly enhanced infected wound healing by day 7, promoting inflammatory response, granular tissue formation, cell proliferation, and angiogenesis. By day 14, T4O-ABC-Zein facilitated complete wound healing, with reepithelization, collagen I deposition, and downregulation of CD 31, Ki67, and α-SMA. Overall, the innovative T4O-ABC-Zein composite, with an aligned fiber structure, improved biocompatibility, and antimicrobial properties, holds significant potential for the treatment of infected wounds.

Ultrasound-responsive microfibers promoted infected wound healing with neuro-vascularization by segmented sonodynamic therapy and electrical stimulation

Bacteria-infected wounds pose challenges to healing due to persistent infection and associated damage to nerves and vessels. Although sonodynamic therapy can help kill bacteria, it is limited by the residual oxidative stress, resulting in prolonged inflammation. To tackle these barriers, novel 4 octyl itaconate-coated Li-doped ZnO/PLLA piezoelectric composite microfibers are developed, offering a whole-course "targeted" treatment under ultrasound therapy. The inclusion of Li atoms causes the ZnO lattice distortion and increases the band gap, enhancing the piezoelectric and sonocatalytic properties of the composite microfibers, collaborated by an aligned PLLA conformation design. During the infection and inflammation stages, the piezoelectric microfibers exhibit spatiotemporal-dependent therapeutic effects, swiftly eliminating over 94.2 % of S. aureus within 15 min under sonodynamic therapy. Following this phase, the microfibers capture reactive oxygen species and aid macrophage reprogramming, restoring mitochondrial function, achieving homeostasis, and shortening inflammation cycles. As the wound progresses through the healing stages, bioactive Zn2+ and Li + ions are continuously released, improving cell recruitment, and the piezoelectrical stimulation enhances wound recovery with neuro-vascularization. Compared to commercially available dressings, our microfibers accelerate the closure of rat wounds (Φ = 15 mm) without scarring in 12 days. Overall, this "one stone, four birds" wound management strategy presents a promising avenue for infected wound therapy.

Electrically Active Biomaterials for Stimulation and Regeneration in Tissue Engineering

In the human body, bioelectric cues are crucial for tissue stimulation and regeneration. Electrical stimulation (ES) significantly enhances the regeneration of nerves, bones, cardiovascular tissues, and wounds. However, the use of conventional devices with stimulating metal electrodes is invasive and requires external batteries. Consequently, electrically active materials with excellent biocompatibility have attracted attention for their applications in stimulation and regeneration in tissue engineering. To fully exploit the potential of these materials, biocompatibility, operating mechanisms, electrical properties, and even biodegradability should be carefully considered. In this review, we categorize various electrically active biomaterials based on their mechanisms for generating electrical cues, such as piezoelectric effect, triboelectric effect, and others. We also summarize the key material properties, including electrical characteristics and biodegradability, and describe their applications in tissue stimulation and regeneration for nerves, musculoskeletal tissues, and cardiovascular tissues. The electrically active biomaterials hold great potential for advancing the field of tissue engineering and their demonstrated success underscores the importance of continued research in this field.

Large Scale Ultrafast Manufacturing of Wireless Soft Bioelectronics Enabled by Autonomous Robot Arm Printing Assisted by a Computer Vision-Enabled Guidance System for Personalized Wound Healing

A Customized wound patch for Advanced tissue Regeneration with Electric field (CARE), featuring an autonomous robot arm printing system guided by a computer vision-enabled guidance system for fast image recognition is introduced. CARE addresses the growing demand for flexible, stretchable, and wireless adhesive bioelectronics tailored for electrotherapy, which is suitable for rapid adaptation to individual patients and practical implementation in a comfortable design. The visual guidance system integrating a 6-axis robot arm enables scans from multiple angles to provide a 3D map of complex and curved wounds. The size of electrodes and the geometries of power-receiving coil are essential components of the CARE and are determined by a MATLAB simulation, ensuring efficient wireless power transfer. Three heterogeneous inks possessing different rheological behaviors can be extruded and printed sequentially on the flexible substrates, supporting fast manufacturing of large customized bioelectronic patches. CARE can stimulate wounds up to 10 mm in depth with an electric field strength of 88.8 mV mm-1. In vitro studies reveal the ability to accelerate cell migration by a factor of 1.6 and 1.9 for human dermal fibroblasts and human umbilical vein endothelial cells, respectively. This study highlights the potential of CARE as a clinical wound therapy method to accelerate healing.

Innovative Hydrogel Design: Tailoring Immunomodulation for Optimal Chronic Wound Recovery

Despite significant progress in tissue engineering, the full regeneration of chronic wounds persists as a major challenge, with the immune response to tissue damage being a key determinant of the healing process's quality and duration. Post-injury, a crucial aspect is the transition of macrophages from a pro-inflammatory state to an anti-inflammatory. Thus, this alteration in macrophage polarization presents an enticing avenue within the realm of regenerative medicine. Recent advancements have entailed the integration of a myriad of cellular and molecular signals into hydrogel-based constructs, enabling the fine-tuning of immune cell activities during different phases. This discussion explores modern insights into immune cell roles in skin regeneration, underscoring the key role of immune modulation in amplifying the overall efficacy of wounds. Moreover, a comprehensive review is presented on the latest sophisticated technologies employed in the design of immunomodulatory hydrogels to regulate macrophage polarization. Furthermore, the deliberate design of hydrogels to deliver targeted immune stimulation through manipulation of chemistry and cell integration is also emphasized. Moreover, an overview is provided regarding the influence of hydrogel properties on immune traits and tissue regeneration process. Conclusively, the accent is on forthcoming pathways directed toward modulating immune responses in the milieu of chronic healing.

Electroconductive Nanocellulose, a Versatile Hydrogel Platform: From Preparation to Biomedical Engineering Applications

Nanocelluloses have garnered significant attention recently in the attempt to create sustainable, improved functional materials. Nanocellulose possesses wide varieties, including rod-shaped crystalline cellulose nanocrystals and elongated cellulose nanofibers, also known as microfibrillated cellulose. In recent times, nanocellulose has sparked research into a wide range of biomedical applications, which vary from developing 3D printed hydrogel to preparing structures with tunable characteristics. Owing to its multifunctional properties, different categories of nanocellulose, such as cellulose nanocrystals, cellulose nanofibers, and bacterial nanocellulose, as well as their unique properties are discussed here. Here, different methods of nanocellulose-based hydrogel preparation are covered, which include 3D printing and crosslinking methods. Subsequently, advanced nanocellulose-hydrogels addressing conductivity, shape memory, adhesion, and structural color are highlighted. Finally, the application of nanocellulose-based hydrogel in biomedical applications is explored here. In summary, numerous perspectives on novel approaches based on nanocellulose-based research are presented here.

Negative Pressure Smart Patch to Sense and Heal the Wound

Negative pressure wound therapy (NPWT) offers significant advantages in terms of rate and time for healing through generating sub-vacuum to draw out inflammatory exudate and promote wound closure. However, continuous drainage probably leads to healing delay due to the lack of information about the real status of the wound bed and the potential risk of infection. To address this concern, printed Negative Pressure Smart Patch (NPSP) is reported by integrating smart real-time sensing acidity (infection) and glucose, and anti-infection into NPWT systems. In addition, NPSP delivers vancomycin through chitosan porous microspheres under negative pressure to modulate wound healing. Compared with NPWT, NPSP projects a promising approach to removing bacteria, reducing local inflammation, and accelerating healing in a short period of time.

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.

BaTiO3 Doping Enhances Ultrasound-Driven Piezoelectric Bactericidal Effects of Fibrous Poly(L-Lactic Acid) Dressings to Accelerate Septic Wound Healing

Bacterial invasion in infected skin wounds triggers inflammation and impedes healing. Current therapeutic strategies incorporating drug interventions within wound dressings often result in drug resistance and delayed healing. Here, we developed a comprehensive therapeutic modality integrating piezoelectric fibrous dressing with controlled ultrasound stimulation for efficient healing in an infected wound model. The electrospun fibrous dressings composed of barium titanate (BaTiO3) doped poly(L-lactic acid) (PLLA) possess improved piezoelectric properties due to the aligned structure and high crystallinity, which achieved superior bactericidal efficacy upon ultrasound-mechanical-electric conversion that results in the production of reactive oxygen species (ROS). There were 88.72% and 90.43% killing rates of Staphylococcus aureus and Escherichia coli respectively upon ultrasound stimulation without any need for exogenous drugs, and a wound closure rate of 95.5% within 10 days. The in vivo results confirmed that this dressing effectively shortened wound closure time by about 2 days, with a much-improved healing rate of 14% compared with previously reported therapeutic strategies. This was accompanied by reduced inflammation and increased re-epithelialization and angiogenesis. Hence, our synergistic treatment by piezoelectric materials and controlled ultrasound stimulation provides a drug-free alternative approach in regenerative tissue engineering for simultaneously enhancing antibacterial effects and promoting wound healing.

Radial Egg White Hydrogel Releasing Extracellular Vesicles for Cell Fate Guidance and Accelerated Diabetic Skin Regeneration

Topology and bioactive molecules are crucial for stimulating cellular and tissue functions. To regulate the chronic wound microenvironment, mono-assembly technology is employed to fabricate a radial egg white hydrogel loaded with lyophilized adipose tissue-extracellular vesicles (radial EWH@L-EVs). The radial architecture not only significantly modified the gene expression of functional cells, but also achieved directional and controlled release kinetics of L-EVs. Through the synergy of topographical and inherent bioactive cues, radial EWH@L-EVs effectively reduced intracellular oxidative stress and promoted the polarization of macrophages toward an anti-inflammatory phenotype during the inflammatory phase. Afterward, radial EWH@L-EVs facilitated the centripetal migration and proliferation of fibroblasts and endothelial cells as the wound transitioned to the proliferative phase. During the latter remodeling phase, radial EWH@L-EVs accelerated the regeneration of granulation tissue, angiogenesis, and collagen deposition, thereby promoting the reorganization chronic wound. Compared with the gold standard collagen scaffold, radial EWH@L-EVs actively accommodated the microenvironment via various functions throughout all stages of diabetic wound healing. This can be attributed to the orientation of topological structures and bioactive molecules, which should be considered of utmost importance in tissue engineering.

Impact of dcEF on microRNA profiles in glioblastoma and exosomes using a novel microfluidic bioreactor

Glioblastoma multiforme, the most common type of highly aggressive primary brain tumor, is influenced by complex molecular signaling pathways, where microRNAs (miRNAs) play a critical regulatory role. Originating from glial cells, glioblastoma cells are affected by the physiological direct current electric field (dcEF) in the central nervous system. While dcEF has been shown to affect glioblastoma migration (electrotaxis), the specific impact on glioblastoma intercellular communication and miRNA expression in glioblastoma cells and their exosomes remains unclear. This study aims to fill this gap by investigating the differential expression of microRNAs in glioblastoma cells and exosomes under dcEF stimulation. We have developed a novel, reversibly sealed dcEF stimulation bioreactor that ensures uniform dcEF stimulation across a large cell culture area, specifically targeting glioblastoma cells and primary human astrocytes. Using microarray analysis, we examined differential miRNA profiles in both cellular and exosomal RNAs. Our study identified shared molecular targets and pathways affected by dcEF stimulation. Our findings reveal significant changes in miRNA expression due to dcEF stimulation, with specific miRNAs, such as hsa-miR-4440 being up-regulated and hsa-miR-3201 and hsa-mir-548g being down-regulated. Future research will focus on elucidating the molecular mechanisms of these miRNAs and their potential as diagnostic biomarkers. The developed platform offers high-quality dcEF stimulation and rapid sample recovery, with potential applications in tissue engineering and multi-omics molecular analysis.

Implantable Self-Powered Systems for Electrical Stimulation Medical Devices

With the integration of bioelectronics and materials science, implantable self-powered systems for electrical stimulation medical devices have emerged as an innovative therapeutic approach, garnering significant attention in medical research. These devices achieve self-powering through integrated energy conversion modules, such as triboelectric nanogenerators (TENGs) and piezoelectric nanogenerators (PENGs), significantly enhancing the portability and long-term efficacy of therapeutic equipment. This review delves into the design strategies and clinical applications of implantable self-powered systems, encompassing the design and optimization of energy harvesting modules, the selection and fabrication of adaptable electrode materials, innovations in systematic design strategies, and the extensive utilization of implantable self-powered systems in biological therapies, including the treatment of neurological disorders, tissue regeneration engineering, drug delivery, and tumor therapy. Through a comprehensive analysis of the latest research progress, technical challenges, and future directions in these areas, this paper aims to provide valuable insights and inspiration for further research and clinical applications of implantable self-powered systems.

Electrical Microneedles for Wound Treatment

Electrical stimulation has been hotpot research and provoked extensive interest in a broad application such as wound closure, tissue injury repair, and nerve engineering. In particular, immense efforts have been dedicated to developing electrical microneedles, which demonstrate unique features in terms of controllable drug release, real-time monitoring, and therapy, thus greatly accelerating the process of wound healing. Here, a review of state-of-art research concerning electrical microneedles applied for wound treatment is presented. After a comprehensive analysis of the mechanisms of electrical stimulation on wound healing, the derived three types of electrical microneedles are clarified and summarized. Further, their applications in wound healing are highlighted. Finally, current perspectives and directions for the development of future electrical microneedles in improving wound healing are addressed.

A Mg Battery-Integrated Bioelectronic Patch Provides Efficient Electrochemical Stimulations for Wound Healing

Bioelectronic patches hold promise for patient-comfort wound healing providing simplified clinical operation. Currently, they face paramount challenges in establishing long-term effective electronic interfaces with targeted cells and tissues due to the inconsistent energy output and high bio interface impedance. Here a new electrochemical stimulation technology is reported, using a simple wound patch, which integrates the efficient generation and delivery of stimulation. This is realized by employing a hydrogel bioelectronic interface as an active component in an integrated power source (i.e., Mg battery). The Mg battery enhances fibroblast functions (proliferation, migration, and growth factor secretion) and regulates macrophage phenotype (promoting regenerative polarization and down-regulating pro-inflammatory cytokines), by providing an electric field and the ability to control the cellular microenvironment through chemical release. This bioelectronic patch shows an effective and accelerated wound closure by guiding epithelial migration, mediating immune response, and promoting vasculogenesis. This new electrochemical-mediated therapy may provide a new avenue for user-friendly wound management as well as a platform for fundamental insights into cell stimulation.

Hybrid biological macromolecules spider-silk fibroin optical patches for efficient wound healing

Efforts toward developing wound dressings that effectively monitor healing have become at the forefront of the field of wound healing. However, monofunctionality, biotoxicity, and passive therapy constrain wound patches. Herein, a hypoallergenic wound patch integrating moisture monitoring, motion sensing and electrical stimulation for wound healing is presented. Microstructured patches composed of silk proteins and spider silk proteins (MIS) fused together were structurally transformed and crosslinked by spin-coating a mixture of silk proteins (SFs) and spider silk proteins (SPs) with water-soluble polyurethane (PU), creating MIS patches with microstructures by hot embossing. This is attributed to stable SF-SP hydrogen bonding, which provides an extremely rapid response to humidity and endows the patch with superior motion sensing tensile properties. Notably, β-folding and α-helical structures confer SP toughness and strength, producing electrical charges under electrical stimulation occurring with motor stretching, thereby enabling electrical stimulation for quicker wound healing. Specifically, The MIS is sensitive to changes in humidity, which is reflected in changes in the colour of its surface patches. Also it enhances the strength of the electrical stimulation signal more effectively as the thickness of the film layer increases. These characteristics indicate the high potential of the MIS for wound management.

Lysozyme-enhanced cellulose nanofiber, chitosan, and graphene oxide multifunctional nanocomposite for potential burn wound healing applications

The demand for advanced biomaterials in medical treatments is rapidly expanding. To address this demand, a nanocomposite of cellulose nanofiber (CNF) with chitosan (Ch) and graphene oxide (GO) was developed for burn wound treatment. The CNF-Ch-GO nanocomposites were characterized and their biological properties were evaluated. Microscopic images showed a uniform distribution of CNF, Ch, and GO with a porous structure. ATR-FTIR and XRD analyses confirmed the chemical structures, while a thermogravimetric study confirmed the stability of CNF-Ch-GO nanocomposite under a N2 atmosphere. The synthesized CNF-Ch-GO nanocomposite exhibited rapid absorption, absorbing 1781.7 ± 53.7 % PBS in 2 min. It demonstrated a Young's modulus of 11.90 ± 0.06 MPa in a hydrated condition, indicating its mechanical stability in water. Furthermore, it displayed excellent biocompatibility and hemocompatibility with 96.23 ± 12.21 % cell viability and 0.21 ± 0.08 % of hemolysis. Additionally, the blood clotting index of CNF-Ch-GO was comparable to that of standard dressing gauze. To enhance antimicrobial efficacy, CNF-Ch-GO was conjugated with lysozyme. This biotic and abiotic conjugation resulted in 92.17 % ± 3.02 % and 94.99 ± 2.1 % eradication of Escherichia coli and Staphylococcus aureus, respectively. The enhanced antimicrobial properties, biocompatibility, and mechanical stability of the superabsorbent CNF-Ch-GO nanocomposite indicate its significant potential for advanced burn wound healing applications.

Polyphenol-mediated redox-active hydrogel with H2S gaseous-bioelectric coupling for periodontal bone healing in diabetes

Excessive oxidative response, unbalanced immunomodulation, and impaired mesenchymal stem cell function in periodontitis in diabetes makes it a great challenge to achieve integrated periodontal tissue regeneration. Here, a polyphenol-mediated redox-active algin/gelatin hydrogel encapsulating a conductive poly(3,4-ethylenedioxythiopene)-assembled polydopamine-mediated silk microfiber network and a hydrogen sulfide sustained-release system utilizing bovine serum albumin nanoparticles is developed. This hydrogel is found to reverse the hyperglycemic inflammatory microenvironment and enhance functional tissue regeneration in diabetic periodontitis. Polydopamine confers the hydrogel with anti-oxidative and anti-inflammatory activity. The slow, sustained release of hydrogen sulfide from the bovine serum albumin nanoparticles recruits mesenchymal stem cells and promotes subsequent angiogenesis and osteogenesis. Moreover, poly(3,4-ethylenedioxythiopene)-assembled polydopamine-mediated silk microfiber confers the hydrogel with good conductivity, which enables it to transmit endogenous bioelectricity, promote cell arrangement, and increase the inflow of calcium ion. In addition, the synergistic effects of hydrogen sulfide gaseous-bioelectric coupling promotes bone formation by amplifying autophagy in periodontal ligament stem cells and modulating macrophage polarization via lipid metabolism regulation. This study provides innovative insights into the synergistic effects of conductivity, reactive oxygen species scavenging, and hydrogen sulfide on the periodontium in a hyperglycemic inflammatory microenvironment, offering a strategy for the design of gaseous-bioelectric biomaterials to promote functional tissue regeneration in immune-related diseases.

A bioabsorbable mechanoelectric fiber as electrical stimulation suture

In surgical medicine, suturing is the standard treatment for large incisions, yet traditional sutures are limited in functionality. Electrical stimulation is a non-pharmacological therapy that promotes wound healing. In this context, we designed a passive and biodegradable mechanoelectric suture. The suture consists of multi-layer coaxial structure composed of (poly(lactic-co-glycolic acid), polycaprolactone) and magnesium to allow safe degradation. In addition to the excellent mechanical properties, the mechanoelectrical nature of the suture grants the generation of electric fields in response to movement and stretching. This is shown to speed up wound healing by 50% and reduce the risk of infection. This work presents an evolution of the conventional wound closure procedures, using a safe and degradable device ready to be translated into clinical practice.

Piezoelectric Analgesia Blocks Cancer-Induced Bone Pain

The manipulation of cell surface receptors' activity will open a new frontier for drug development and disease treatment. However, limited by the desensitization of drugs, effective physical intervention strategy remains challenging. Here, the controllable internalization of transient receptor potential vanilloid 1 (TRPV1) on neural cells by local piezoelectric field is reported. Single-cell-level local electric field is construct by synthesizing piezoelectric BiOIO3 nanosheets (BIONSs). Upon a mild ultrasound of 0.08 W cm-2, an electric field of 15.29 µV is generated on the surface of BIONSs, further inducing TRPV1 internalization in 5 min. The as-downregulated TRPV1 expression results in the reduction of Ca2+ signal in a spinal neuron and the inhibition of the activity of wide range dynamic neurons, therefore effectively preventing the transmission of cancer-induced bone pain (CIBP). This strategy not only charts a new course for CIBP alleviation, but also introduces a promising nanotechnology for regulating cell surface receptors, showing significant potential in neuropathological and receptor-related diseases.

Construction and Performance Study of a Dual-Network Hydrogel Dressing Mimicking Skin Pore Drainage for Photothermal Exudate Removal and On-Demand Dissolution

In recent years, negative pressure wound dressings have garnered widespread attentions. However, it is challenging to drain the accumulated fluid under negative pressures for hydrogel dressings. To address this issue, this study prepared a chemical/physical duel-network PEG-CMCS/AG/MXene hydrogel composed by chemical disulfide crosslinked network of four-arm polyethylene glycol/carboxymethyl chitosan (4-Arm-PEG-SH/CMCS), and the physical network of hydrogen bond of agar (AG). Under near-infrared light (NIR) irradiation, the PEG-CMCS/AG/MXene hydrogel undergoes photothermal heating due to integrate of MXene, which destructs the hydrogen bond network and allows the removal of exudate through a mechanism mimicking the sweat gland-like effect of skin pores. The photothermal heating effect also enables the antimicrobial activity to prevent wound infections. The excellent electrical conductivity of PEG-CMCS/AG/MXene can promote cell proliferation under the external electrical stimulation (ES) in vitro. The animal experiments of full-thickness skin defect model further demonstrate its ability to accelerate wound healing. The conversion between thioester and thiol achieved with L-cysteine methyl ester hydrochloride (L-CME) can provides the on-demand dissolution of the dressing in situ. This study holds promises to provide a novel solution to the issue of fluid accumulations under hydrogel dressings and offers new approaches to alleviating or avoiding the significant secondary injuries caused by frequent dressing changes.

Smart Dressings and Their Applications in Chronic Wound Management

During chronic wound healing, the inflammatory phase can endure for extended periods, heavily impeding or halting the process. Regular inspections and dressing changes are crucial. Modern dressings like hydrogels, hydrocolloids, and foam provide protection and an optimal healing environment. However, they have limitations in offering real-time wound bed status and healing rate. Evaluation relies heavily on direct observation, and passive dressings fail to identify subtle healing differences, preventing adaptive adjustments in biological factors and drug concentrations. In recent years, the clinical field recognizes the value of integrating intelligent diagnostic tools into wound dressings. By monitoring biomarkers linked to chronic wounds' inflammatory state, real-time data can be captured, reducing medical interventions and enabling more effective treatment plans. This fosters innovation in chronic wound care. Researchers have developed smart dressings with sensing, active drug delivery, and self-adjustment capabilities. These dressings detect inflammatory markers like temperature, pH, and oxygen content, enhancing drug bioavailability on the wound surface. As wound healing technology evolves, these smart dressings hold immense potential in chronic wound care and treatment. This comprehensive review updates our understanding on the role and mechanism of action of the smart dressings in chronic refractory wounds by summarizing and discussing the latest research progresses, including the intelligent monitoring of wound oxygen content, temperature, humidity, pH, infection, and enzyme kinetics; intelligent drug delivery triggered by temperature, pH, near-infrared, and electricity; as well as the intelligent self-adjustment of pressure and shape. The review also delves into the constraints and future perspectives of smart dressings in clinical settings, thereby advancing the development of smart wound dressings for chronic wound healing and their practical application in clinical practice.

Water-powered, electronics-free dressings that electrically stimulate wounds for rapid wound closure

Chronic wounds affect ~2% of the U.S. population and increase risks of amputation and mortality. Unfortunately, treatments for such wounds are often expensive, complex, and only moderately effective. Electrotherapy represents a cost-effective treatment; however, its reliance on bulky equipment limits its clinical use. Here, we introduce water-powered, electronics-free dressings (WPEDs) that offer a unique solution to this issue. The WPED performs even under harsh conditions-situations wherein many present treatments fail. It uses a flexible, biocompatible magnesium-silver/silver chloride battery and a pair of stimulation electrodes; upon the addition of water, the battery creates a radial electric field. Experiments in diabetic mice confirm the WPED's ability to accelerate wound closure and promote healing by increasing epidermal thickness, modulating inflammation, and promoting angiogenesis. Across preclinical wound models, the WPED-treated group heals faster than the control with wound closure rates comparable to treatments requiring expensive biologics and/or complex electronics. The results demonstrate the WPED's potential as an effective and more practical wound treatment dressing.

Magneto-responsive biocomposites in wound healing: from characteristics to functions

The number of patients with non-healing wounds continuously increases, and has become a prominent societal issue that imposes a heavy burden on both patients and the entire healthcare system. Although traditional dressings play an important role in wound healing, the complexity and diversity of the healing process pose serious challenges in this field. Magneto-responsive biocomposites, with their excellent biocompatibility, remote spatiotemporal controllability, and unique convenience, demonstrate enticing advantages in the field of wound dressings. However, current research on magneto-responsive biocomposites as wound dressings lacks comprehensive and in-depth reviews, which to some extent, restricts the deeper understanding and further development of this field. Based on this, this paper reviews the latest advances in magnetic responsive wound dressings for wound healing. First, we review the process of skin wound healing and parameters for assessing repair progress. Then, we systematically discuss the preparation strategies and unique characteristics of magneto-responsive biocomposites, focusing on magneto-induced orientation, magneto-induced mechanical stimulation, and magnetocaloric effect. Subsequently, this review elaborates the multiple mechanisms of magneto-responsive biocomposites in promoting wound healing, including regulating cell behavior, enhancing electrical signal, controlling drug release, and accelerating tissue reconstruction. Finally, we further propose the development direction and future challenges of magnetic responsive biomaterials as wound dressings in clinical application.

Red-light-excited TiO2/Bi2S3 heterojunction nanotubes and photoelectric hydrogels mediate epidermal-neural network reconstruction in deep burns

Inspired by the strong light absorption of carbon nanotubes, we propose a fabrication approach involving one-dimensional TiO2/Bi2S3 QDs nanotubes (TBNTs) with visible red-light excitable photoelectric properties. By integrating the construction of heterojunctions, quantum confinement effects, and morphological modifications, the photocurrent reached 9.22 µA/cm2 which is 66 times greater than that of TiO2 nanotubes (TNTs). Then, a red light-responsive photoelectroactive hydrogel dressing (TBCHA) was developed by embedding TBNTs into a collagen/hyaluronic acid-based biomimetic extracellular matrix hydrogel with good biocompatibility, aiming to promote wound healing and skin function restoration. This approach is primarily grounded in the recognized significance of electrical stimulation in modulating nerve function and immune responses. Severe burns are often accompanied by extensive damage to epithelial-neural networks, leading to a loss of excitatory function and difficulty in spontaneous healing, while conventional dressings inadequately address the critical need for nerve reinnervation. Furthermore, we highlight the remarkable ability of the TBCHA photoelectric hydrogel to promote the reinnervation of nerve endings, facilitate the repair of skin substructures, and modulate immune responses in a deep burn model. This hydrogel not only underpins wound closure and collagen synthesis but also advances vascular reformation, immune modulation, and neural restoration. This photoelectric-based therapy offers a robust solution for the comprehensive repair of deep burns and functional tissue regeneration. STATEMENT OF SIGNIFICANCE: We explore the fabrication of 1D TiO2/Bi2S3 nanotubes with visible red-light excitability and high photoelectric conversion properties. By integrating heterojunctions, quantum absorption effects, and morphological modifications, the photocurrent of TiO2/Bi2S3 nanotubes could reach 9.22 µA/cm², which is 66 times greater than that of TiO2 nanotubes under 625 nm illumination. The efficient red-light excitability solves the problem of poor biosafety and low tissue penetration caused by shortwave excitation. Furthermore, we highlight the remarkable ability of the TiO2/Bi2S3 nanotubes integrated photoelectric hydrogel in promoting the reinnervation of nerve endings and modulating immune responses. This work proposes an emerging therapeutic strategy of remote, passive electrical stimulation, offering a robust boost for repairing deep burn wounds.

Stimuli-Mediated Macrophage Switching, Unraveling the Dynamics at the Nanoplatforms-Macrophage Interface

Macrophages play an essential role in immunotherapy and tissue regeneration owing to their remarkable plasticity and diverse functions. Recent bioengineering developments have focused on using external physical stimuli such as electric and magnetic fields, temperature, and compressive stress, among others, on micro/nanostructures to induce macrophage polarization, thereby increasing their therapeutic potential. However, it is difficult to find a concise review of the interaction between physical stimuli, advanced micro/nanostructures, and macrophage polarization. This review examines the present research on physical stimuli-induced macrophage polarization on micro/nanoplatforms, emphasizing the synergistic role of fabricated structure and stimulation for advanced immunotherapy and tissue regeneration. A concise overview of the research advancements investigating the impact of physical stimuli, including electric fields, magnetic fields, compressive forces, fluid shear stress, photothermal stimuli, and multiple stimulations on the polarization of macrophages within complex engineered structures, is provided. The prospective implications of these strategies in regenerative medicine and immunotherapeutic approaches are highlighted. This review will aid in creating stimuli-responsive platforms for immunomodulation and tissue regeneration.

Flexible self-powered bioelectronics enables personalized health management from diagnosis to therapy

Flexible self-powered bioelectronics (FSPBs), incorporating flexible electronic features in biomedical applications, have revolutionized the human-machine interface since they hold the potential to offer natural and seamless human interactions while overcoming the limitations of battery-dependent power sources. Furthermore, as biosensors or actuators, FSPBs can dynamically monitor physiological signals to reveal real-time health abnormalities and provide timely and precise treatments. Therefore, FSPBs are increasingly shaping the landscape of health monitoring and disease treatment, weaving a sophisticated and personalized bond between humans and health management. Here, we examine the recent advanced progress of FSPBs in developing working mechanisms, design strategies, and structural configurations toward personalized health management, emphasizing its role in clinical medical scenarios from biophysical/biochemical sensors for sensing diagnosis to robust/biodegradable actuators for intervention therapy. Future perspectives on the challenges and opportunities in emerging multifunctional FSPBs for the next-generation health management systems are also forecasted.

A comprehensive exploration of hydrogel applications in multi-stage skin wound healing

Hydrogels, as an emerging biomaterial, have found extensive use in the healing of wounds due to their distinctive physicochemical structure and functional properties. Moreover, hydrogels can be made to match a range of therapeutic requirements for materials used in wound healing through specific functional modifications. This review provides a step-by-step explanation of the processes involved in cutaneous wound healing, including hemostasis, inflammation, proliferation, and reconstitution, along with an investigation of the factors that impact these processes. Furthermore, a thorough analysis is conducted on the various stages of the wound healing process at which functional hydrogels are implemented, including hemostasis, anti-infection measures, encouraging regeneration, scar reduction, and wound monitoring. Next, the latest progress of multifunctional hydrogels for wound healing and the methods to achieve these functions are discussed in depth and categorized for elucidation. Finally, perspectives and challenges associated with the clinical applications of multifunctional hydrogels are discussed.

Electric fields reverse the differentiation of keratinocyte monolayer by down-regulating E-cadherin through PI3K/AKT/Snail pathway

Re-epithelialization is an important step in skin wound healing, referring to the migration, proliferation, and differentiation of keratinocytes around the wound. During this process, the edges of the wound begin to form new epithelial cells, which migrate from the periphery of the wound towards the center, gradually covering the entire wound area. These newly formed epithelial cells proliferate and differentiate, ultimately forming a protective layer over the exposed dermal surface. Wound endogenous electric fields (EFs) are known as the dominant factor to facilitate the epidermal migration to wound center. However, the precise mechanisms by which EFs promote epidermal migration remains elusive. Here, we found that in a model of cultured keratinocyte monolayer in vitro, EFs application reversed the differentiation of cells, as indicated by the reduction of the early differentiation markers K1 and K10. Genetic manipulation confirmed that EFs reversed keratinocyte differentiation through down-regulating the E-cadherin-mediated adhesion. By RNA-sequencing analysis, we screened out Snail as the transcription suppressor of E-cadherin. Snail knockdown abolished the down-regulation of E-cadherin and the reversal of differentiation induced by EFs. KEGG analysis identified PI3K/AKT signaling for Snail induction under EFs. Inhibition of PI3K by LY294002 diminished the EFs-induced AKT activation and Snail augmentation, largely restoring the level of E-cadherin reduced by EFs. Finally, in model of full-thickness skin wounds in pigs, we found that weakening of the wound endogenous EFs by the direction-reversed exogenous EFs resulted in an up-regulation of E-cadherin and earlier differentiation in newly formed epidermis in vivo. Our research suggests that electric fields (EFs) decrease E-cadherin expression by suppressing the PI3K/AKT/Snail pathway, thereby reversing the differentiation of keratinocytes. This discovery provides us with new insights into the role of electric fields in wound healing. EFs intervene in intracellular signaling pathways, inhibiting the expression of E-cadherin, which results in a lower differentiation state of keratinocytes. In this state, keratinocytes exhibit increased migratory capacity, facilitating the migration of epidermal cells and wound reepithelialization.

A bioelectronic device for electric field treatment of wounds reduces inflammation in an in vivo mouse model

Electrical signaling plays a crucial role in the cellular response to tissue injury in wound healing and an external electric field (EF) may expedite the healing process. Here, we have developed a standalone, wearable, and programmable electronic device to administer a well-controlled exogenous EF, aiming to accelerate wound healing in an in vivo mouse model to provide pre-clinical evidence. We monitored the healing process by assessing the re-epithelization rate and the ratio of M1/M2 macrophage phenotypes through histology staining. Following three days of treatment, the M1/M2 macrophage ratio decreased by 30.6% and the re-epithelization in the EF-treated wounds trended towards a non-statically significant 24.2% increase compared to the control. These findings provide point towards the effectiveness of the device in shortening the inflammatory phase by promoting reparative macrophages over inflammatory macrophages, and in speeding up re-epithelialization. Our wearable device supports the rationale for the application of programmed EFs for wound management in vivo and provides an exciting basis for further development of our technology based on the modulation of macrophages and inflammation to better wound healing.

Electroactive Biomaterials Regulate the Electrophysiological Microenvironment to Promote Bone and Cartilage Tissue Regeneration

The incidence of large bone and articular cartilage defects caused by traumatic injury is increasing worldwide; the tissue regeneration process for these injuries is lengthy due to limited self‐healing ability. Endogenous bioelectrical phenomenon has been well recognized to play an important role in bone and cartilage homeostasis and regeneration. Studies have reported that electrical stimulation (ES) can effectively regulate various biological processes and holds promise as an external intervention to enhance the synthesis of the extracellular matrix, thereby accelerating the process of bone and cartilage regeneration. Hence, electroactive biomaterials have been considered a biomimetic approach to ensure functional recovery by integrating various physiological signals, including electrical, biochemical, and mechanical signals. This review will discuss the role of endogenous bioelectricity in bone and cartilage tissue, as well as the effects of ES on cellular behaviors. Then, recent advances in electroactive materials and their applications in bone and cartilage tissue regeneration are systematically overviewed, with a focus on their advantages and disadvantages as tissue repair materials and performances in the modulation of cell fate. Finally, the significance of mimicking the electrophysiological microenvironment of target tissue is emphasized and future development challenges of electroactive biomaterials for bone and cartilage repair strategies are proposed.

All-in-One Self-Powered Microneedle Device for Accelerating Infected Diabetic Wound Repair

Diabetic wound healing remains a significant clinical challenge due to the complex microenvironment and attenuated endogenous electric field. Herein, a novel all-in-one self-powered microneedle device (termed TZ@mMN-TENG) is developed by combining the multifunctional microneedle carried tannin@ZnO microparticles (TZ@mMN) with the self-powered triboelectric nanogenerator (TENG). In addition to the delivery of tannin and Zn2+, TZ@mMN also effectively conducts electrical stimulation (ES) to infected diabetic wounds. As a self-powered device, the TENG can convert biomechanical motion into exogenous ES to accelerate the infected diabetic wound healing. In vitro experiment demonstrated that TZ@mMN shows excellent conductive, high antioxidant ability, and effective antibacterial properties against both Staphylococcus aureus and Escherichia coli (>99% antibacterial rates). Besides, the TZ@mMN-TENG can effectively promote cell proliferation and migration. In the diabetic rat full-thickness skin wound model infected with Staphylococcus aureus, the TZ@mMN-TENG can eliminate bacteria, accelerate epidermal growth (regenerative epidermis: ≈303.3 ± 19.1 µm), enhance collagen deposition, inhibit inflammation (lower TNF-α and IL-6 expression), and promote angiogenesis (higher CD31 and VEGF expression) to accelerate infected wound repair. Overall, the TZ@mMN-TENG provides a promising strategy for clinical application in diabetic wound repair.

Photomechaelectric Nanogenerators with Different Photoisomers and Dipole Units for Harvesting UV Light Energy

To date, transforming environmental energy into electricity through a non-mechanical way is challenging. Herein, a series of photomechaelectric (PME) polyurethanes containing azobenzene-based photoisomer units and ionic liquid-based dipole units are synthesized, and corresponding PME nanogenerators (PME-NGs) to harvest electricity are fabricated. The dependence of the output performance of PME-NGs on the structure of the polyurethane is evaluated. The results show that the UV light energy can directly transduce into alternating-current (AC) electricity by PME-NGs via a non-mechanical way. The optimal open-circuit voltage and short-circuit current of PME-NGs under UV illumination reach 17.4 V and 696 µA, respectively. After rectification, the AC electricity can be further transformed into direct-current (DC) electricity and stored in a capacitor to serve as a power system to actuate typical microelectronics. The output performance of PME-NGs is closely related to the hard segment content of the PME polyurethane and the radius of counter anions in the dipole units. Kelvin probe force microscopy is used to confirm the existence of the PME effect and the detailed mechanism about the generation of AC electricity in PME-NGs is proposed, referring to the back and forth drift of induced electrons on the two electrodes in contact with the PME polyurethanes.