Accelerated Skin Wound Healing by Electrical Stimulation

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 microfluidic co-culture platform for lung cancer cells electrotaxis study under the existence of stromal cells

Tumor metastasis is an important reason for the poor prognosis and high mortality in cancer patients. As major component of stromal cells in tumor microenvironment, cancer-associated fibroblasts (CAFs) secreted various factors to promote tumor metastasis. Studies have indicated that endogenous direct current electric field (dcEF) around tumor tissue induced directional migration of cancer cells. However, the regulatory effect of CAFs on cancer migration under dcEF stimulation is still unknown. In this study, a two-layers polydimethylsiloxane (PDMS)-based microfluidic chip was fabricated. The introduction of concave structures achieved the non-contacted co-culture of different cell types, and parallel channels in the chip provided stable and homogeneous dcEF. Cells electrotactic response was evaluated under co-culture circumstance. The results showed that CAFs exhibited directional migration towards anode under dcEF stimulation, while A549 cells had a trend of directional migration towards cathode. The co-existence of CAFs and dcEF significantly enhanced the motility and cathodal migration of A549 cells, suggesting synergistic influences of chemotaxis from CAFs and electrotaxis from dcEF stimulation. Moreover, we demonstrated that lung normal fibroblasts acquired CAFs properties after stimulated by dcEF, characterizing by increasing gene expression of α-SMA and IL-6. Overall, Our device and study provide new insight for tumor electrotaxis in complex microenvironment.

Promotion of quiescence and maintenance of function of mesenchymal stem cells on substrates with surface potential

The widespread use of human mesenchymal stem cells(hMSCs) is impeded by functional loss during prolonged expansion. Although multiple approaches have been attempted to preserve hMSCs stemness, a suitable culture system remains to be modified. The interaction between electrical signals and stem cells is expected to better maintain the function of stem cells. However, it remains unclear whether the surface potential of substrates has the potential to preserve stem cell function during in vitro expansion. In our study, hMSCs cultured on materials with different surface potentials could be induced into a reversible quiescent state, and we demonstrated that quiescent hMSCs could be reactivated and transitioned back into the proliferation cell cycle. hMSCs cultured under appropriate potential displayed superior differentiation and proliferation abilities within the same generation compared to conventional conditions. These findings underscore the importance of surface potential as a critical physical factor regulating hMSCs stemness. Manipulating the surface potential of hMSCs culture substrates holds promise for optimising preservation and culture conditions, thereby enhancing their application in tissue repair and regeneration engineering.

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.

Fully biodegradable ion-induced silk fibroin-based triboelectric nanogenerators with enhanced performance prevent muscle atrophy

Applying electrical stimulation (ES) on nerve or muscle denervation can significantly restore the nerve function and prevent muscle atrophy. The triboelectric nanogenerator (TENG) can couple the mechanical energy and electrical energy for ES. However, the triboelectric performance of fully biodegradable TENGs and the effect of ES need to be optimized and verified. Here, the triboelectric performance of silk fibroin (SF) is regulated by ions to fabricate SF-TENGs with full biodegradability, good biocompatibility, and excellent output. This SF-TENG shows a good electrostimulation recovery effect and is used for function restoration of the injured sciatic nerve and innervated muscle. Li+ effectively improves the dielectric constant and increases the positively charged ability of SF. The highest output power density of SF-TENG is 128 mW/m2, which is superior to most reported fully biodegradable TENGs. The morphology, protein expression levels, neural/muscular function are assessed to evaluate the recovery of damaged nerves and innervated muscle. The function restoration of the injured nerve and innervated muscle under ES of SF-TENG is significantly close to the normal nerve and muscle. This TENG has great potential to achieve in vivo energy generation, ES, and biodegradability as an implantable electrical stimulator for the therapy of nerve, muscle, and tissue injury.

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.

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.

Electric Stimulation Combined with Biomaterials for Repairing Spinal Cord Injury

Spinal cord injury (SCI) is a central nervous system (CNS) disease with a high disability rate, and reconstructing motor function after SCI remains a global challenge. Recent advancements in rehabilitation and regenerative medicine offer new approaches to SCI repair. Electrical stimulation has been shown to alter cell membrane charge distribution, generating action potentials, and affecting cell behavior. This method aids axon regeneration and neurotrophic factor upregulation, crucial for nerve repair. Biomaterials, used as scaffolds or coatings in cell culture and tissue engineering, enhance cell proliferation, migration, differentiation, and tissue regeneration. Electroactive biomaterials combined with electrical stimulation show promise in regenerating nerve, heart, and bone tissues. In this paper, different types of electrical stimulation and biomaterials applied to SCI are described, and the current application and research progress of electrical stimulation combined with biomaterials in the treatment of SCI are described, as well as the future prospects and challenges.

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.

Flexible Amorphous Silicon Radial Junction Patches Promote Skin Regeneration by Offering Wireless Photoelectric Neuromodulation

Photoelectric stimulation offers a promising method for creating noninvasive and durable interfaces with biological tissues, particularly in treating nerve injuries. However, developing flexible and high-performance photoelectric stimulators remains a challenge. In this study, we present an accessible and cost-effective strategy for fabricating an ultraflexible and biocompatible photoelectric patch designed for wireless, light-induced electrical stimulation to promote nerve repair in skin wounds. Using low-temperature chemical vapor deposition, we created flexible photoelectric films based on three-dimensional (3D) amorphous silicon radial p-i-n junction (RJ) nanowires, which exhibit a high open-circuit voltage of 0.79 V and a short-circuit current of 10.5 mA/cm2 under standard AM 1.5 G illumination conditions. The device exhibits good electrochemical performance in solution, featuring high interfacial capacitance and efficient photocurrent generation (∼0.64 mA/cm2), which ensures a stable, capacitive charge injection crucial for effective bioelectrical stimulation. Importantly, the free-standing RJ films can be reliably transferred onto soft poly(dimethylsiloxane) substrates to produce flexible photoelectric patches that maintain intimate contact with curved tissue surfaces. The RJ patches show high biocompatibility and effectively enhance neurite outgrowth and wound healing under safe visible light, promoting both vascular regeneration and neural restoration. This flexible patch holds potential in wireless electrical stimulation, providing a robust and noninvasive solution for comprehensive wound repair and functional tissue regeneration.

A self-powered casein hydrogel E-dressing with synergistic photothermal therapy, electrical stimulation, and antibacterial effects for chronic wound management

Triboelectric nanogenerators (TENGs) have recently demonstrated great application potential for accelerating wound healing in the field of medical research due to their unique electrical stimulation effect. Among the various types of TENGs, solid-liquid TENGs have attracted much attention due to their significant advantages, such as high contact-separation efficiency and a wide range of liquid motion. Therefore, this study innovatively proposed a solid-liquid biphasic TENG electronic dressing constructed from a casein hydrogel enhanced by the metal-organic framework Zeolitic Imidazolate Framework-8 (ZIF-8). This hydrogel dressing comprised sodium caseinate (SC)/multi-walled carbon nanotubes-polydopamine@polydopamine (MWCNT@PDA)/polyacrylamide (PAM)/ZIF-8. It ingeniously integrates multiple functions such as photothermal, photodynamic antibacterial, and electrical stimulation therapies, thereby establishing a new multimodal synergistic treatment paradigm. Notably, the addition of ZIF-8 not only controlled photothermal release of antibacterial agents but also facilitates the development of a distinctive solid-liquid biphasic operational modality in TENG system, achieving a 131 V peak output voltage through significant enhancement of electrical performance parameters. In addition, the TENG-based system adopts a non-contact electrical stimulation method for wound treatment, fundamentally reducing the risk of infection caused by direct contact. Experiments using mouse fibroblasts revealed that the simultaneous real-time use of near-infrared light and TENG can significantly improve the cell migration process. Empirical studies on animals demonstrated that it could accelerate tissue regeneration and wound healing by increasing collagen deposition and angiogenesis. Based on these results, this study provides new perspectives for the developing intelligent biomedical composites for future wound management. STATEMENT OF SIGNIFICANCE: Chronic wounds have become a major threat to global medical and health fields due to pathogenic infections. Traditional wound dressings mostly focus on passive healing, which has limited effectiveness. To overcome these limitations, we developed an electronic dressing of a casein-based hydrogel TENG enhanced by a MOF. This electronic dressing combines photothermal, photodynamic antibacterial, and electrical stimulation functions and efficiently promotes wound healing through multifunctional synergy. This research provides a promising solution for diabetic wound care and a broader field of chronic wound treatment. It is a solid step in the scientific exploration of interdisciplinary integration, offering new ideas for making the wound treatment field more intelligent, efficient, and precise.

MXenes in the application of diabetic foot: mechanisms, therapeutic implications and future perspectives

Diabetic foot represents a significant healthcare challenge, accounting for a substantial portion of diabetes-related hospitalizations and amputations globally. The complexity of diabetic foot management stems from the interplay of poor glycemic control, neuropathy, and peripheral vascular disease, which hinder wound healing processes. The high incidence, recurrence, and amputation rates associated with diabetic foot underscore the urgency for innovative treatment strategies. Recent advancements in nanotechnology, particularly the emergence of MXenes (two-dimensional transition metal carbides and/or nitrides), have shown promising potential in addressing these challenges by offering unique physicochemical and biological properties suitable for various biomedical applications. It is a novel potential strategy for diabetic foot wound healing in the future. This review comprehensively summarizes current knowledge, unique characteristics, and underlying mechanisms of MXenes in the context of diabetic foot management. Additionally, we propose the potential application of MXenes-based therapeutic strategies in diabetes foot. Furthermore, we also provide an overview of their current challenges and the future perspectives in related fields of diabetic wound healing.

Piezoelectret Textile Dressing for Biosignal Monitored Wound Healing

In recent years, smart textile sensors have gained exponential growth in various sectors such as wearable technology and healthcare. However, addressing the demand for wearable textiles that offer both exceptional functionality (e.g., air-permeability, flexibility) and comfort remains a significant challenge. In this context, a rotary jet-spun textile piezoelectret is demonstrated, which is not reported so far. The piezoelectric output of the all-organic textile sensor is improved by 150% in voltage and 200% for current upon electrical poling. The finite element method revealed that the enhanced piezo-potential is attributed to the trapped polarized charges within the piezoelectret matrix. It exhibited outstanding piezoelectric properties with sensitivity of 400 mV kPa-1 (pressure range, 0.6-7 kPa), waterproofness (water contact angle ≈134°) and high breathability (10 kg m-2 per day), ensuring wearer comfort. Apart from monitoring different physiological signals such as pulse and respiratory rate, it also acted as a sensor array that displays the deep learning-aided pressure mapping with the accuracy of 98%. In addition, this textile accelerated faster proliferation and migration of L929 cell due to its piezoelectricity induced electrical stimulation, suggesting its potential application in wound dressings. Thus, this approach has huge potential to offer a scalable and versatile solution for biomedical technology.

Dual-regulation biomimetic composite nerve scaffold with oriented structure and conductive function for skin peripheral nerve injury repair

Skin peripheral nerve injury repair still faces significant clinical challenges. Although nerve tissue engineering scaffolds show potential, issues such as limited functionality and low repair efficiency persist. This study developed a dual-regulation biomimetic composite nerve scaffold with oriented structure and conductive function to promote nerve injury repair. The structural layer was a chitosan (CS)/polycaprolactone (PCL) oriented nanofiber membrane, which could promote cell adhesion and induce directional growth of cells. The functional layer was a CS/sodium alginate (SA) ionic conductive hydrogel, which could enhance endogenous electric fields to promote cell proliferation and differentiation. The two layers were combined through physical crosslinking, avoiding the use of chemical adhesives and preserving the surface morphology of the nanofibrous membrane and the porous structure of the hydrogel. The biomimetic composite nerve scaffold exhibited layered degradability, excellent orientation, conductivity, and biocompatibility. Cell experiments indicated that the scaffold effectively induced directional migration, growth, and differentiation of cells and enhanced cell activity, thereby providing a favorable microenvironment for nerve regeneration. This study not only overcomes the limitation of functional singularity in traditional nerve scaffolds but also aligns with the forefront trend in tissue engineering toward multifunctional and biomimetic materials. It demonstrates great potential for treating complex conditions such as traumatic nerve defects and post-surgical nerve regeneration and has broad application prospects in the field of neural tissue engineering.

Piezoelectric dual-network tough hydrogel with on-demand thermal contraction and sonopiezoelectric effect for promoting infected-joint-skin-wound healing via FAK and AKT signaling pathways

The dynamic and whole stage management of infected wound healing throughout the entire repair process, including intelligent on-demand wound closure and the regulation of the transition from bactericidal to reparative phases, remains a major challenge. This study develops sonopiezoelectric-effect-mediated on-demand reactive-oxygen-species release by incorporating piezoelectric barium titanate modified with gold nanoparticles and a thermally responsive dual-network tough hydrogel dressing with a physical network structure based on ureidopyrimidinone-modified gelatin crosslinked by multiple hydrogen bonds, and with a chemical network structure based on N-isopropylacrylamide and methacryloyl gelatin formed via radical polymerization. This hydrogel exhibits temperature-sensitive softening, on-demand thermal contraction performance, high mechanical strength, good tissue adhesion, outstanding piezoelectricity, tunable sonopiezoelectric behavior, regulatable photothermal properties and desirable biocompatibility. The tunable sonopiezoelectric effect enables the hydrogel to eliminate wound bacteria in the short term, and effectively promote human fibroblast proliferation and migration over the long term. The hydrogel dressing actively contracts to close wound edges and further promotes the healing of MRSA-infected skin defects in the neck of mice by promoting fibroblast migration, enhancing collagen deposition and facilitating angiogenesis via up-regulating the FAK and AKT signaling pathways, providing a novel design strategy for developing dressings targeting chronic joint-skin wounds.

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.

Sound Wave-Activated Self-Powered Adhesive Dressing for Accelerated Wound Healing

Self-powered wound dressings are effective in treating chronic wounds because of their low toxicity and convenience. However, current self-powered dressings rely on the bending movements of the skin or additional large ultrasonic devices. Herein, a flexible adhesive self-powered wound dressing (FASW) that promotes skin regeneration through daily sound wave driving without relying on skin bending or external sound devices is proposed. The FASW dressing consists of a bioadhesive film (BAF), a unidirectional fluorinated conductive film (UFCF), and a liquid metal (LM) interlayer. Benefiting from the cross-linking of chitosan, the dressing exhibits excellent properties, such as biocompatibility, stretchability, tissue adhesion, and recyclability. In vivo experiments show that the FASW dressing reduced inflammation and stimulated hair follicle regeneration. This wound dressing utilizes previously overlooked natural energies for the treatment of chronic wounds, thereby enhancing the therapeutic effect of traditional self-powered dressings on individuals with movement disorders.

Advances in the study of polysaccharide-based hydrogel wound dressings

Due to the complexity of wound healing, the rapid promotion of wound healing has been a major unresolved challenge for the medical community. If a suitable wound dressing is not found, it can easily induce wound infection and slow down the wound repair process. Hydrogels have been recognized as the best alternative to traditional wound dressings due to their unique water-retention properties as well as their drug-carrying properties. We first outlined the entire process of wound healing, while introducing the biological activities of ten different natural polysaccharides and their mechanisms for promoting wound healing. Subsequently, we summarized the advantages and limitations of various polysaccharides in use and proposed corresponding solutions. In addition, wound dressings for a wide range of wounds, including diabetes, burns, and radiation, have also been reviewed, providing a comprehensive understanding of the applications of these hydrogels in different wound types. This paper provides an important reference for the biomedical application and clinical research of natural polysaccharide-based hydrogel in wound dressings.

Calcium-ion-driving assembly of polysaccharide deriving from Zizyphus jujuba to hemostatic hydrogel for treating diabetic wound

Due to good biocompatibility and biodegradable, natural polysaccharide-based hydrogels have received worldwide attentions, where polysaccharide polymers were usually chemically modified to meet the specific elastic requirements. However, it remained highly challenging to develop polysaccharide-based hydrogels with desired mechanical properties and biological functions devoid of any structural modifications. Herein, with the coordination of Ca2+ (15.0 mM), the jujuba polysaccharide (JPS, 1 %) was facilely fabricated to a hydrogel (JPS-gel) within 1 min at pH 10, where the residual proteins also played crucial roles on the assembly. The JPS-gel showed outstanding stability and mechanical properties, which were tunable by adjusting the content of Ca2+/JPS. The JPS-gel also revealed excellent biocompatibility, and could expedite the migration and proliferation of healing-related cells, angiogenesis and alleviate inflammation response. More interestingly, the JPS-gel had hemostatic capacity, where the hemostatic time and blood loss in liver incision model were 13 ± 3 s and 6.3 ± 1.6 mg after 120 s treatment with JPS-gel, respectively. All these superiorities endowed JPS-gel high performance healing in diabetic wounds (10 days). Specially, the expressions of inflammation-related genes were downregulated, but gene expressions associated with cell migration and proliferation, and angiogenesis were upregulated, thus uncovering the action mechanism of JPS-gel on accelerating wound contraction.

Bacterial microenvironment-responsive antibacterial, adhesive, and injectable oxidized dextran-based hydrogel for chronic diabetic wound healing

Diabetic wounds are highly susceptible to bacterial infections, often resulting in chronic wounds that pose a substantial challenge to clinical treatment. Furthermore, the irregular shapes of these wounds limit the effectiveness of conventional dressings. Therefore, development of a new type of antibacterial dressing that can accommodate various wound shapes is urgently required. In this study, we designed injectable hydrogels with bacterial microenvironment-responsive antibacterial, adhesive, and antioxidant properties. These hydrogels were developed by incorporating polydopamine nanoparticles (PDA NPs) into a gelatin/oxidized dextran (Gel-oDex) network crosslinked via dynamic Schiff base reactions. Notably, the Gel-oDex-PDA-PHMB hydrogel demonstrated strong antibacterial efficacy against S. aureus, E. coli, and MRSA (all exceeding 99%), with PHMB-release experiments confirming its responsiveness to the bacterial microenvironment. Additionally, the hydrogel exhibited significant antioxidant activity, as evidenced by the DPPH radical scavenging assays. With good biocompatibility, the Gel-oDex-PDA-PHMB hydrogel also demonstrated effectiveness in killing bacteria and promoting the regeneration and functional reconstruction of skin tissue in bacteria-infected diabetic rats.

Efficacy of electrical stimulation for antimicrobial capacity of titanium materials implants: a systematic review and meta-analysis

BACKGROUND

Antimicrobial resistance undermines the effectiveness of drugs for treating implant-associated infections. Consequently, there is growing interest in identifying alternative methods to prevent and eliminate infections. The aim of this systematic review was to ascertain whether the electrical stimulation of titanium implants or titanium-based implant materials has antimicrobial properties against bacterial biofilms. The search was conducted in various databases, including PubMed/Medline, Web of Science, EMBASE, SCOPUS, and Google Scholar, in February 2024. In addition, a manual search of the reference lists of the included articles was conducted. The eligibility criteria included in vivo and in vitro studies evaluating the effects of electrical stimulation on titanium implants or titanium-based implant materials in reducing biofilm formation or adhesion as well as eradicating or reducing the viability of bacterial biofilms. The variability between studies was determined using the inverse variance method with random- and fixed-effects models. Heterogeneity was assessed using the I2 and prediction interval statistics. Publication bias was qualitatively evaluated using funnel plots.

HIGHLIGHTS

Different electrical stimulation (ES) parameters (current and voltage) exhibited antibacterial activity, resulting in either bacteriostatic or bactericidal effects.

CONCLUSIONS

ES in titanium or titanium-based implant materials confers antimicrobial capacity against bacterial biofilms, and its effectiveness depends on the applied tension. The association between ES and antimicrobials was more robust than with ES administered individually.

Self-Powered Thermoelectric Hydrogels Accelerate Wound Healing

Electrical stimulation (ES) serves as a biological cue that regulates critical cellular processes, including proliferation and migration, offering an effective approach to accelerating wound healing. Thermoelectrics, capable of generating electricity by exploiting the temperature difference between skin and the surrounding environment without external energy input, present a promising avenue for ES-based therapies. Herein, we developed Ag2Se@gelatin methacrylate (Ag2Se@GelMA) thermoelectric hydrogels with high room-temperature thermoelectric performance and employed them as self-powered ES devices for wound repair. Systematic in vivo and in vitro investigations elucidated their biological mechanisms for enhancing wound healing. Our findings reveal that the Ag2Se@GelMA thermoelectric hydrogels can significantly accelerate the wound closure by amplifying the endogenous electric field, thereby promoting cell proliferation, migration, and angiogenesis. Comprehensive in vitro experiments demonstrated that ES generated by the hydrogels activates voltage-gated calcium ion channels, elevating intracellular Ca2+ levels and enhancing mitochondrial functions through the Ca2+/CaMKKβ/AMPK/Nrf2 pathway. This cascade improves mitochondrial dynamics and angiogenesis, thereby accelerating tissue regeneration. The newly developed Ag2Se@GelMA thermoelectric hydrogels represent a marked progress in wound dressing technology with the potential to improve clinical strategies in tissue engineering and regenerative medicine.

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.

Flexible fibrous electrodes for implantable biosensing

Flexible fibrous electrodes have emerged as a promising technology for implantable biosensing applications, offering significant advancements in the monitoring and manipulation of biological signals. This review systematically explores the key aspects of flexible fibrous electrodes, including the materials, structural designs, and fabrication methods. A detailed discussion of electrode performance metrics is provided, covering factors such as conductivity, stretchability, axial channel count, and implantation duration. The diverse applications of these electrodes in electrophysiological signal monitoring, electrochemical sensing, tissue strain monitoring, and in vivo electrical stimulation are reviewed, highlighting their potential in biomedical settings. Finally, the review discusses the eight major challenges currently faced by implantable fibrous electrodes and explores future development directions, providing critical technical analysis and potential solutions for the advancement of next-generation flexible implantable fiber-based biosensors.

Microneedle hierarchical structure construction for promoting multi-stage wound healing

As a new type of drug delivery system, microneedle have received extensive attention in wound healing due to their penetrability, painlessness, and high drug delivery efficiency. However, microneedle are often unable to penetrate the skin completely due to the limitations of the skin's mechanical properties, resulting in low drug delivery efficiency during wound repair. Therefore, it is particularly important to optimize the multi-level structural design of microneedles. This article systematically summarizes the multi-level structural design of microneedles that promote wound healing, including the structural parameters of a single microneedle, microneedle array design, and microneedle system structural optimization. It also summarizes the research progress on the functional design of microneedle systems at various stages of wound repair. This paper reviews the current status and limitations of microneedle patch design, and provides theoretical guidance for the design of smart microneedle wound management/healing.

Functional hydrogels for accelerated wound healing: advances in conductive hydrogels and self-powered electrical stimulation

Compared to traditional dressings, hydrogel dressings not only protect the wound surface and prevent bacterial infection but also possess excellent moisturizing properties, which can provide an optimal moist environment for wound healing, and exhibit good biocompatibility, making them considered the best wound treatment materials. This review focuses on the research status and application progress of various functional hydrogel dressings, such as hemostatic, antimicrobial, anti-inflammatory, antioxidant, and conductive hydrogels. It proposes the combination of conductive hydrogels with flexible solar cells to form self-powered devices. Compared to traditional externally powered devices, this approach can reduce carbon footprints by utilizing clean energy, aligning with carbon neutrality policy requirements. Additionally, it eliminates the need for frequent battery replacement or power connections, effectively saving labor and operational costs. Self-powered devices can convert solar energy into electrical energy, which is conducted to the wound site through hydrogels, generating continuous electrical stimulation (ES). This electrical stimulation guides the directional migration of keratinocytes and fibroblasts toward the center of the wound; activates the MAPK/ERK signaling pathway to accelerate the cell cycle process, and upregulates the expression of vascular endothelial growth factor, thereby inducing endothelial cell proliferation and lumen formation. These multiple mechanisms work synergistically to promote wound healing. Finally, the review provides an outlook on the emergence and applications of multifunctional hydrogels and stimuli-responsive hydrogels, highlighting common challenges in the future development of hydrogels, such as weak mechanical strength and poor long-term stability, as well as feasible solutions to these issues.

Electret-Inspired Charge-Injected Hydrogel for Scar-Free Healing of Bacterially Infected Burns Through Bioelectrical Stimulation and Immune Modulation

In this study, an electret-inspired, charge-injected hydrogel called QOSP hydrogel (QCS/OD/SDI/PANI/PS/Plasma) that promotes scar-free healing of bacteria-infected burns through bioelectrical stimulation and immune modulation, is presented. The hydrogel, composed of quaternized chitosan (QCS), oxidized dextran (OD), sulfadiazine (SDI), polystyrene (PS), and polyaniline nanowires (PANI), forms a conductive network capable of storing and releasing electric charges, emulating an electret-like mechanism. This structure delivers bioelectrical signals continuously, enhancing wound healing by regulating immune responses and minimizing fibrosis. In a mouse model of second-degree burns infected with Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA), the hydrogel accelerates wound healing by 32% and reduces bacterial load by 60%, significantly inhibited scar formation by 40% compared to controls. QOSP hydrogel modulates the Th1/Th2 immune balance toward a Th1-dominant antifibrotic state through quaternized chitosan, thereby reducing collagen deposition by 35%. Electro-dielectric characterization reveals a dielectric constant of 6.2, a 34% improvement in conductivity (3.33 × 10-5 S/m) and a 30 °C increase in thermal stability. Proteomic analysis highlights a 50% down-regulation of pro-inflammatory and pro-fibrotic pathways, suggesting a controlled immune response conducive to scar-free healing. This study underscores the potential of bioelectrically active hydrogels as a novel approach for treating infected wounds prone to scarring.

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.

Polysaccharides, proteins and DNA based stimulus responsive hydrogels promoting wound healing and repair: A review

The healing of various wounds remains a serious challenge in the medical field, hydrogel has high hydrophilicity and biocompatibility due to its unique network structure, which shows a strong advantage in the field of wound healing. Stimulus responsive hydrogels are particularly effective，which can control the material properties according to the external stimulus source, and provide more targeted treatment for different wounds. Here, we review physiological mechanisms of wound healing and the relationship between polysaccharides, proteins and DNA based stimulus responsive hydrogels and wound healing, materials commonly used of polysaccharides, proteins and DNA based stimulus responsive hydrogels, mechanisms of stimulus responsive hydrogels formation and network structure types, common properties of polysaccharides, proteins and DNA based stimulus responsive hydrogels for promoting wound healing and discuss their applications in medicine. Finally, the limitations and application prospects of polysaccharides, proteins and DNA based stimulus responsive hydrogels were discussed and evaluated. The review focuses on the biomedical use of polysaccharides, proteins and DNA based stimulus responsive hydrogels in wound healing and repair, and provides insights for the development of clinical related materials.

Research progress on MXenes in polysaccharide-based hemostasis and wound healing: A review

Traumatic events occur frequently in daily life, and hemostasis and infection prevention represent key challenges in trauma care. Polysaccharide-based materials (chitosan, cellulose, etc.) are widely used as hemostasis materials due to their excellent designability and biocompatibility. However, their insufficient antibacterial activity and limited hemostatic capabilities diminish their effectiveness in wound care. As emerging two-dimensional nanomaterials, MXene offers promising solutions to these limitations. With superior hydrophilicity, antibacterial properties and biocompatibility, MXene enhances the performance of polysaccharide-based hemostasis materials. This review summarizes the characteristics and synthesis methods of MXenes and outlines recent advances in MXene/polysaccharide composites for promoting wound healing by controlling bleeding and preventing infection. Additionally, we discuss the preparation methods, the mechanisms of action, and challenges in practical applications of MXene/polysaccharide composites, and propose future research directions. By integrating the advantages of MXenes and polysaccharides, we hope to provide a more effective solution for the research of polysaccharide-based hemostatic materials.

Alternating electrical fields to stimulate osteogenic cells and biomimetic calcium phosphate-coated titanium substrates-A combinatorial approach to bone regeneration

Biophysical stimuli such as alternating electrical fields can mimic endogenous electrical potentials and currents in natural bone. This can help to improve the healing and reconstruction of bone tissue. However, little is known about the combined influence of biomaterials and alternating electric fields on bone cells. Therefore, this study aimed to investigate the impact of both, biomaterials and alternating electric fields, on osteoblast as well as osteoclast differentiation. Initially, either RAW 264.7 or MC3T3-E1 cells were seeded on Ti6Al4V substrates as a load-bearing implant material, modified with biomimetic calcium phosphate (BCP), or uncoated as a reference. The cells were stimulated towards osteoclastic and osteoblastic differentiation via respective growth factors. The effects of BCP substrate modification on cell differentiation were examined after 7 days for RAW 264.7 and after 14 days for MC3T3-E1 cells. In a further series of tests, either RAW 264.7 or MC3T3-E1 cells were seeded on BCP-modified Ti6Al4V substrates, stimulated towards differentiation using growth factors, and further electrically stimulated via alternating electric fields of different voltages and frequencies. In parallel to the first test series RAW 264.7 and MC3T3-E1 cells were stimulated for 7 and 14 days, respectively. Cell morphology was examined via scanning electron microscopy. Cell viabilities were assessed via WST-8 assay. Electrically stimulated MC3T3-E1 cell orientation was evaluated based on fluorescence microscopy images. Marker genes were examined via qPCR. While BCP increased osteoclast-specific gene expression, it had the opposite effect on osteoblast-related genes compared to respective cells seeded on uncoated Ti6Al4V substrates. ES with different parameters showed a broad cellular response due to electrocoupling. While cell viability assessments and gene expression analyses showed clear differences between ES samples and unstimulated controls, only minor cell morphology and orientation differences were observed. Furthermore, there was no clear trend towards a dominant influence of either voltage or frequency as control parameters. Further studies were initiated to investigate the underlying intracellular mechanisms targeted by ES. This work provides an introduction to the targeted control of cellular processes using defined electric fields. The optimization of voltage and frequency could provide therapeutic windows to control specific cellular functions and potentially improve bone regeneration and remodeling processes.

Advancing Chronic Wound Healing through Electrical Stimulation and Adipose-Derived Stem Cells

Chronic cutaneous wounds are a major clinical challenge worldwide due to delayed healing, recurrent infections, and resistance to conventional therapies. Adipose-derived stem cells (ASCs) have shown promise as a cell-based therapy, but their therapeutic efficacy is often compromised by the harsh microenvironment of chronic wounds. Recent advances in bioengineering, particularly the application of electrical stimulation (ES), offer an innovative approach to enhancing the regenerative properties of ASCs. By restoring the natural electrical current in the wound, ES provides a strong stimulus to the cells involved in healing, thereby accelerating the overall wound-healing process. Recent studies show that ASCs can be significantly activated by ES, which increases their viability, proliferation, migration, and secretory capacity, all of which are crucial for the proper healing of chronic wounds. This review examines the synergistic effects of ES and ASCs on wound healing, focusing on the biological mechanisms involved. The review also highlights novel self-powered systems and other emerging technologies such as advanced conductive materials and devices that promise to improve the clinical translation of ES-based treatments. By summarizing the current state of knowledge, this review aims to provide a framework for future research and clinical application of ES and ASCs in wound care.

3D Bioprinting of Double-Layer Conductive Skin for Wound Healing

Conductive hydrogels are highly attractive in 3D bioprinting of tissue engineered scaffolds for skin injury repair. However, their application is limited by mismatched electrical signal conduction mode and poor printability. Herein, the 3D bioprinting-assisted fabrication of a double-layer ionic conductive skin scaffold using a newly designed ionic conductive biomimetic bioink (GHCM) is reported, which is composed of gelatin methacrylate (GelMA), oxidized hyaluronic acid (OHA), carboxymethyl chitosan (CMCS), and 2-methacryloyloxyethyl phosphorylcholine (MPC) for the treatment of full-thickness skin defects. The combination of rigid (GelMA) and dynamic (OHA-CMCS) polymer networks imparts GHCM bioink excellent reversible thixotropy, enabling good printability, and allowing the creation of skin-like constructs with high shape fidelity and cell activity by convenient one-step bioprinting. Moreover, the incorporation of zwitterionic MPC endows the bioink with electrical signaling pattern similar to that of natural skin tissue. By integrating human foreskin fibroblasts (HFF-1), human umbilical vein endothelial cells (HUVECs), and human immortalized keratinocytes (HaCaTs), a double-layer conductive skin scaffold comprising an epidermal layer and a vascularized dermal layer is created. In vivo experiments have demonstrated that the conductive skin scaffolds provide an appropriate conductive microenvironment for cellular signaling, growth, migration, and differentiation, ultimately accelerating the re-epithelialization, collagen deposition, and vascularization of skin wounds, which may represent a general and versatile strategy for precise engineering of electroactive tissues for regenerative medicine applications.

Electrostimulation combined with biodegradable electroactive oriented nanofiber polycaprolactone/gelatin/carbon nanotube to accelerate wound healing

Wound healing is a complex but precise physiological process. Howener, existing treatments are often difficult to meet the needs of different wound healing. With the background that exogenous electrical stimulation (ES) has been proven to be effective in regulating cell behavior, we constructed a electroactive wound dressing derived from carbon nanotubes (CNT) by electrospinning technology. The scaffold has a moderate hydrophilicity, which benefits to collecting of effusion, adhering to the wound site, and safely removing. Furthermore, the oriented structure has the potential to promote cell oriented growth, while the coupling of endogenous electric field (EFs) and ES could effectively regulate the phenotype of macrophages and reshape the immune microenvironment. At the same time, the active electrical stimulation promotes the secretion of active factors and the proliferation and migration of fibroblasts and endothelial cells. In vivo assays further confirm that PCL/GE/CNT combined ES strategy can significantly inhibit the early inflammatory response, while promoting vascular regeneration and collagen deposition. RNA sequencing analysis is used to reveal the mechanism at the molecular level. Overall, this study employed a composite strategy of combining CNT with moderately hydrophilic biocompatible nanofibers to achieve ES delivery simply and effectively, significantly improving tissue engineering outcomes. This innovative strategy provides a feasible approach for efficient wound repair, and provides an important experimental basis and theoretical guidance for future development in the field of skin tissue engineering.

Ta-Ag Coatings on TC4: A Strategy to Leverage Bioelectric Microenvironments for Enhanced Antibacterial Activity

Dental implant-related infections are serious complications after surgery that can results in loosening or even complete loss of the implant. Although endogenous electric fields (EEF) play an integral role in the human body, current methods involving external electrical stimulation are invasive and not suitable for clinical application. In this study, we using DC magnetron sputtering, investigates the effects of tantalum-silver (Ta-Ag) coatings on titanium alloy (TC4) surfaces, focusing on their potential to influence EEF that enhances antibacterial activity In this design, Ta-Ag configuration effectively increased the surface potential difference of TC4, and furthermore, promoting Ta/Ag ions release and reducing bacterial adhesion. The study concludes that the Ta-Ag coating, particularly the TT/A implant, promotes a stable EEF, enhancing the long-term antibacterial and osteogenic properties of implants. This work provides a promising strategy for developing advanced implant materials with improved clinical efficacy.

A General Strategy for Exceptionally Robust Conducting Polymer-Based Bioelectrodes with Multimodal Capabilities Through Decoupled Charge Transport Mechanisms

Bioelectrodes function as a critical interface for signal transduction between living organisms and electronics. Conducting polymers (CPs), particularly poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), are among the most promising materials for bioelectrodes, due to their electrical performance, high compactness, and ease of processing, but often suffer from degradation or de-doping even in some common environments (e.g., electrical stimulation, chemicals, and high temperatures). This instability therefore severely undermines their reliability in practical application. To resolve this critical issue, a novel strategy of separating electron transfer from electron-ion transduction is proposed. Specifically, chemically derived holey graphene (HG), serving as an ultra-stable mixed ion-electron conductor, is introduced into the CP matrix. The HG can restore the CP's destructed conductive pathways, whilst its porosity and its intercalation by the CP synergically preserve fast ionic and molecular diffusion. The resulting bioelectrode therefore exhibits excellent low impedance, high charge injection capacity, electrochemical activity, and outstanding resilience to various harsh conditions, outperforming HG, reduced graphene oxide, CP, or graphene-coated CP electrodes. Furthermore, this strategy also exhibits broad compatibility with various processing techniques and proves adaptable to other electrode systems, such as stretchable electrodes, paving the way for practical applications in electrophysical capture, neuron modulation, and biochemical analysis.

Acteoside-Loaded Self-Healing Hydrogel Enhances Skin Wound Healing through Modulation of Hair Follicle Stem Cells

Background

Skin wound healing is a complex biological process involving cellular, molecular, and physiological events. Traditional treatments often fail to provide optimal outcomes, particularly for chronic wounds.

Objectives

This study aimed to develop a self-healing hydrogel loaded with Acteoside, a bioactive compound with antioxidant and anti-inflammatory properties, to enhance skin wound healing.

Methods

Using transcriptomic analysis, Rab31 was identified as a key target of Acteoside in regulating hair follicle stem cells (HFSCs). In vitro assays demonstrated that Acteoside promotes HFSC proliferation, migration, and differentiation by upregulating Rab31 expression. The self-healing hydrogel was prepared using quaternized chitosan derivatives, which exhibited excellent mechanical properties, antibacterial, and antioxidant activities.

Results

In vivo studies in a mouse model showed that Acteoside-loaded hydrogel significantly accelerated wound healing, promoting skin regeneration and improving wound closure.

Conclusions

This research highlights the potential of Acteoside-loaded self-healing hydrogels as an innovative therapeutic strategy for enhancing skin wound healing. By modulating HFSC activity, this hydrogel offers a promising solution for improving healing outcomes in challenging wound environments.

Graphical Abstract

Schematic representation of an injectable self-healing hydrogel loaded with the phenylethanoid compound acteoside for regulating the proliferation and differentiation of HFSCs to mediate the healing of skin wounds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-025-00845-2.

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.

Inhibitory effects on smooth muscle cell adhesion and proliferation due to oscillating electric fields by nanogenerators

A common complication of the removal of atherosclerotic plaques or thrombi deposits to restore blood flow is restenosis. It is known that the excessive adhesion and proliferation of smooth muscle cells (SMCs) is the primary reason for restenosis. In this work, we conducted an in vitro study to show that a weak oscillating electric field (EF) generated by a mechanically-driven nanogenerator could prohibit SMC adhesion and proliferation on a substrate surface. Our results revealed a decrease in the cell number when an oscillating EF was introduced underneath the substrate. The cell coverage was found to be dependent on the EF strength and oscillating frequency, where higher EF strength and frequency yielded a stronger inhibitory effect. Compared to the control, this reduction in cell coverage reached up to 54% under the optimal EF parameters. This inhibitory effect was attributed to the EF-induced surface charge oscillation, which weakened the electrostatic interaction between the cell membrane and substrate. Our discovery suggests the potential for self-powered anti-restenosis solutions by integrating NG-induced oscillating EFs with biomedical device surfaces.

Stimuli-Responsive Self-Healing Ionic Gels: A Promising Approach for Dermal and Tissue Engineering Applications

The rapid increase in the number of stimuli-responsive polymers, also known as smart polymers, has significantly advanced their applications in various fields. These polymers can respond to multiple stimuli, such as temperature, pH, solvent, ionic strength, light, and electrical and magnetic fields, making them highly valuable in both the academic and industrial sectors. Recent studies have focused on developing hydrogels with self-healing properties that can autonomously recover their structural integrity and mechanical properties after damage. These hydrogels, formed through dynamic covalent reactions, exhibit superior biocompatibility, mechanical strength, and responsiveness to stimuli, particularly pH changes. However, conventional hydrogels are limited by their weak and brittle nature. To address this, ionizable moieties within polyelectrolytes can be tuned to create ionically cross-linked hydrogels, leveraging natural polymers such as alginate, chitosan, hyaluronic acid, and cellulose. The integration of ionic liquids into these hydrogels enhances their mechanical properties and conductivity, positioning them as significant self-healing agents. This review focuses on the emerging field of stimuli-responsive ionic-based hydrogels and explores their potential in dermal applications and tissue engineering.

Bioelectrically Reprogramming Hydrogels Rejuvenate Vascularized Bone Regeneration in Senescence

Senescent bone tissue displays a pathological imbalance characterized by decreased angiogenesis, disrupted bioelectric signaling, ion dysregulation, and reduced stem cell differentiation. Once bone defects occur, this pathological imbalance makes them difficult to repair. An innovative synergistic therapeutic strategy is utilized to reverse these pathological imbalances via a conductive hydrogel doped with magnesium ion (Mg2+)-modified black phosphorus (BP). The hydrogel reprograms electrical signals, restores Mg2+ homeostasis, reconstructs physiological signals, and promotes blood vessel regeneration in senile bone defects. The conductive hydrogel synergistically restores both the chemical and bioelectric signals within the bone microenvironment. This hydrogel increases the expression of vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR2), activates the PI3K-AKT-eNOS pathway, and significantly increases the angiogenic ability of vascular endothelial cells in the aged state. In addition, the conductive hydrogel normalizes calcium ion (Ca2+) influx, increases the accumulation of osteogenic transcription factors in the nucleus, and promotes the osteogenic differentiation of senescent stem cells. This innovative treatment strategy restores bone-vascular coupling in areas of senile bone defects, achieves effective vascularized bone regeneration, and has good potential for the treatment of senile bone defects.

Electrically-driven drug delivery into deep cutaneous tissue by conductive microneedles for fungal infection eradication and protective immunity

Fungal infections affect over 13 million people worldwide and are responsible for 1.5 million deaths annually. Some deep cutaneous fungal infections may extend the dermal barriers to cause systemic infection, resulting in substantial morbidity and mortality. However, the management of deep cutaneous fungal infection is challenging and yet overlooked by traditional treatments, which only offer limited drug availability within deep tissue. In this study, we have developed an electrically stimulated microneedle patch to deliver miconazole into the subcutaneous layer. We tested its antifungal efficacy using in vitro and ex vivo models that mimic fungal infection. Moreover, we confirmed its anti-fungal and wound-healing effects in a murine subcutaneous fungal infection model. Furthermore, our findings also showed that the combination of miconazole and applied current synergistically stimulated the nociceptive sensory nerves, thereby activating protective cutaneous immunity mediated by dermal dendritic and γδ-T cells. Collectively, this study provides a new strategy for minimally invasive delivery of therapeutic agents and the modulation of the neuro-immune axis in deep tissue.

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.

Low-temperature cold plasma promotes wound healing by inhibiting skin inflammation and improving skin microbiome

Wound healing includes four consecutive and overlapping stages of hemostasis, inflammation, proliferation, and remodeling. Factors such as aging, infection, and chronic diseases can lead to chronic wounds and delayed healing. Low-temperature cold plasma (LTCP) is an emerging physical therapy for wound healing, characterized by its safety, environmental friendliness, and ease of operation. This study utilized a self-developed LTCP device to investigate its biological effects and mechanisms on wound healing in adult and elderly mice. Histopathological studies found that LTCP significantly accelerated the healing rate of skin wounds in mice, with particularly pronounced effects in elderly mice. LTCP can markedly inhibit the expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and senescence-associated secretory phenotype factors (MMP-3, MMP-9), while significantly increasing the expression of tissue repair-related factors, such as VEGF, bFGF, TGF-β, COL-I, and α-SMA. It also regulated the expression of genes related to cell proliferation and migration (Aqp5, Spint1), inflammation response (Nlrp3, Icam1), and angiogenesis (Ptx3, Thbs1), promoting cell proliferation and inhibit apoptosis. Furthermore, LTCP treatment reduced the relative abundance of harmful bacteria such as Delftia, Stenotrophomonas, Enterococcus, and Enterobacter in skin wounds, while increasing the relative abundance of beneficial bacteria such as Muribaculaceae, Acinetobacter, Lachnospiraceae NK4A136_group, and un_f__Lachnospiraceae, thereby improving the microbial community structure of skin wounds. These research findings are of significant implications for understanding the mechanism of skin wound healing, as well as for the treatment and clinical applications of skin wounds, especially aging skin.

Self-powered biomedical devices: biology, materials, and their interfaces

Integrating biomedical electronic devices holds profound promise for advancements in healthcare and enhancing individuals' quality of life. However, the persistent challenges associated with the traditional batteries' limited lifespan and bulkiness hinder these devices' long-term functionality and consistent power supply. Here, we delve into the biology and material interfaces in self-powered medical devices by summarizing the intrinsic electric demands in humans, analyzing material and biological mechanisms for electricity generation and storage, and discussing the pathways toward self-chargeable powering. As a result, the current challenges in material designs and biological integrations emerged to shape the future directions in advancing self-powered medical devices. This paper calls on the community to integrate biology and material science to develop self-powering medical devices and improve their clinical prospects.

Effect of 10 kV/m Electric Field Therapy in a Pressure Injury Model in Rats: An Innovative Preliminary Report

Background: Pressure injuries are still an important health problem worldwide, although many therapies have been applied to date. This study aimed to determine the optimal duration of external application of a 10 kV/m direct current (DC, static) electric field in a pressure injury model in rats. Methods: Twelve male Wistar-Albino rats were divided into three groups: Grade-1, Grade-2, and Grade-3. Two round magnets were placed 4 h daily for one day in Grade-1, two days in Grade-2, and three days in Grade-3. Following wound formation, one rat from each group was designated the control, while the other rats were exposed to a 10 kV/m electric field for 15, 30, or 60 min. Results: Histopathological improvements were observed after 15 and 30 min of application, whereas a sharp decrease in the gene expression of growth factors at 30 min revealed that 15 min of application was optimal overall. Conclusions: According to the results of this study, 15 min applications of an external 10 kV/m electric field are promising for providing satisfactory results in wound healing. Further studies should examine in greater detail the effects of electric fields on growth factors and the mechanisms underlying these responses.

Microneedles in diabetic wound care: multifunctional solutions for enhanced healing

Diabetic wounds present a significant challenge in clinical treatment and are characterized by chronic inflammation, oxidative stress, impaired angiogenesis, peripheral neuropathy, and a heightened risk of infection during the healing process. By creating small channels in the surface of the skin, microneedle technology offers a minimally invasive and efficient approach for drug delivery and treatment. This article begins by outlining the biological foundation of normal skin wound healing and the unique pathophysiological mechanisms of diabetic wounds. It then delves into the various types, materials, and preparation processes of microneedles. The focus is on the application of multifunctional microneedles in diabetic wound treatment, highlighting their antibacterial, anti-inflammatory, immunomodulatory, antioxidant, angiogenic and neural repair properties. These multifunctional microneedles demonstrate synergistic therapeutic effects by directly influencing the wound microenvironment, ultimately accelerating the healing of diabetic wounds. The advancement of microneedle technology not only holds promise for enhancing the treatment outcomes of diabetic wounds but also offers new strategies for addressing other chronic wounds.

Harnessing stimuli-responsive biomaterials for advanced biomedical applications

Cell behavior is intricately intertwined with the in vivo microenvironment and endogenous pathways. The ability to guide cellular behavior toward specific goals can be achieved by external stimuli, notably electricity, light, ultrasound, and magnetism, simultaneously harnessed through biomaterial-mediated responses. These external triggers become focal points within the body due to interactions with biomaterials, facilitating a range of cellular pathways: electrical signal transmission, biochemical cues, drug release, cell loading, and modulation of mechanical stress. Stimulus-responsive biomaterials hold immense potential in biomedical research, establishing themselves as a pivotal focal point in interdisciplinary pursuits. This comprehensive review systematically elucidates prevalent physical stimuli and their corresponding biomaterial response mechanisms. Moreover, it delves deeply into the application of biomaterials within the domain of biomedicine. A balanced assessment of distinct physical stimulation techniques is provided, along with a discussion of their merits and limitations. The review aims to shed light on the future trajectory of physical stimulus-responsive biomaterials in disease treatment and outline their application prospects and potential for future development. This review is poised to spark novel concepts for advancing intelligent, stimulus-responsive biomaterials.

Piezoelectric nanocomposite electrospun dressings: Tailoring mechanics for scar-free wound recovery

Rational wound management and enhancing healing quality are critical in clinical practice. Electrical stimulation therapy (EST) has emerged as a valuable adjunctive treatment due to its safety and cost-effectiveness. Integrating piezoelectric materials into dressings offers a way to miniaturize and personalize electrotherapy, enhancing convenience. To address the impact of physical factors of dressings on wound healing, a nanocomposite piezoelectric electrospun dressing using poly(L-lactic acid) (PLLA) and barium titanate (BaTiO3) was developed. We intentionally exaggerated design flaws to mimic the characteristics of scar extracellular matrix (ECM), including the oriented thick fibers and high Young's modulus. Initially, these dressings promoted fibrosis and hindered functional regeneration. However, when the piezoelectric effect was triggered by ultrasound, the fibrotic phenotype was reversed, leading to scar-free healing with well-regenerated functional structures. This study highlights the significant therapeutic potential of piezoelectric dressings in skin wound treatment and underscores the importance of carefully designing the static physical properties of dressings for optimal efficacy.