Flexible, Breathable, and Self-Powered Patch Assembled of Electrospun Polymer Triboelectric Layers and Polypyrrole-Coated Electrode for Infected Chronic Wound Healing

Obstructed vein delivery of ceftriaxone via poly(vinyl-pyrrolidone)-iodine-chitosan nanofibers for the management of diabetic foot infections and burn wounds

Superficial skin injuries especially burn injuries and unhealed diabetic foot open wounds remain troubling for public health. The healing process is often interrupted by the invasion of resistant pathogens that results in the failure of conventional procedures outside the clinical settings. Herein, we designed nanofibers dressing with intrinsic antibacterial potential of poly(vinyl-pyrrolidone)-iodine/ poly (vinyl)-alcohol by electrospinning with chitosan encapsulating ceftriaxone (CPC/NFs). The optimized electrospun CPC/NFs exhibited smooth surface morphology with average diameter of 165 ± 7.1 nm, drug entrapment and loading efficiencies of 76.97 ± 4.7 % and 8.32 ± 1.73 %, respectively. The results displayed smooth and uniformed fibers with adequate thermal stability and ensured chemical doping. The enhanced in vitro antibacterial efficacy of CPC/NFs against resistant E. coli isolates and biosafety studies encourage the use of designed nanofibers dressing for burn injuries and diabetic foot injuries. In vivo studies proved the healing power of dressing for burn wounds model and diabetic infected wounds model. Immunofluorescence investigation of the wound tissue also suggested promising healing ability of CPC/NFs. The designed approach would be helpful to treat these infected skin open wounds in the hospitals and outside the clinical settings.

α-Lactalbumin based scaffolds for infected wound healing and tissue regeneration

Interruption of wound healing by multi-drug resistant-bacterial infection is a harmful issue for the worldwide health care system, and conventional treatment approaches may not resolve this issue due to antimicrobial resistance. So, there is an unmet need to develop scaffolds with intrinsic wound healing properties to combat bacterial-infected wounds. Inspired by the α-lactalbumin's (Lalb's) ability to promote collagen synthesis, we herein electrospun Lalb with cephalexin (CPL) and epigallocatechin (EP) to produce nanofibers (CE-Lalb NFs) to solve this issue. The CE-Lalb NFs were prepared using the electrospinning technique and subjected to physicochemical characterizations, in vitro, and in vivo assessments. The CE-Lalb NFs promoted fibroblast migration, proliferation, and collagen synthesis, while CPL/EP annihilated MRSA and E. coli infections. Physicochemical characterizations proved the successful fabrication and doping of CE-Lalb NFs. Antimicrobial assays and fractional inhibitory concentration index (FICI) declared synergistic antibacterial activity of CE-Lalb NFs against MRSA and E. coli. The in vivo and immunohistochemical data evidenced its exceptional potential for wound healing, promoting growth factor, collagen synthesis, and reduced scar formation. The presence of mature collagen, fewer inflammatory cytokines, increased expression of blood vessels, and low expression of IL-6 at the wound site support in vitro and in vivo results. In our view, the tailored scaffold is the next step for personalized wound dressings that could meet patients with infected wounds' unmet needs by the subscription of noninvasive and easily navigable therapeutic options.

Bioelectronics for electrical stimulation: materials, devices and biomedical applications

Bioelectronics is a hot research topic, yet an important tool, as it facilitates the creation of advanced medical devices that interact with biological systems to effectively diagnose, monitor and treat a broad spectrum of health conditions. Electrical stimulation (ES) is a pivotal technique in bioelectronics, offering a precise, non-pharmacological means to modulate and control biological processes across molecular, cellular, tissue, and organ levels. This method holds the potential to restore or enhance physiological functions compromised by diseases or injuries by integrating sophisticated electrical signals, device interfaces, and designs tailored to specific biological mechanisms. This review explains the mechanisms by which ES influences cellular behaviors, introduces the essential stimulation principles, discusses the performance requirements for optimal ES systems, and highlights the representative applications. From this review, we can realize the potential of ES based bioelectronics in therapy, regenerative medicine and rehabilitation engineering technologies, ranging from tissue engineering to neurological technologies, and the modulation of cardiovascular and cognitive functions. This review underscores the versatility of ES in various biomedical contexts and emphasizes the need to adapt to complex biological and clinical landscapes it addresses.

A coaxial electrospun mat coupled with piezoelectric stimulation and atorvastatin for rapid vascularized bone regeneration

The repair of critical bone defects caused by various clinical conditions needs to be addressed urgently, and the regeneration of large bone defects depends on early vascularization. Therefore, enhanced vascularization of artificial bone grafts may be a promising strategy for the regeneration of critical-sized bone defects. Taking into account the importance of rapid angiogenesis during bone repair and the potential of piezoelectric stimulation in promoting bone regeneration, novel coaxial electrospun mats coupled with piezoelectric materials and angiogenic drugs were fabricated in this study using coaxial electrospinning technology, with a shell layer loaded with atorvastatin (AVT) and a core layer loaded with zinc oxide (ZnO). AVT was used as an angiogenesis inducer, and piezoelectric stimulation generated by the zinc oxide was used as an osteogenesis enhancer. The multifunctional mats were characterized in terms of morphology, core-shell structure, piezoelectric properties, drug release, and mechanical properties, and their osteogenic and angiogenic capabilities were validated in vivo and ex vivo. The results revealed that the coaxial electrospun mats exhibit a porous surface morphology and nanofibers with a core-shell structure, and the piezoelectricity of the mats improved with increasing ZnO content. Excellent biocompatibility, hydrophilicity and cell adhesion were observed in the multifunctional mats. Early and rapid release of AVT in the fibrous shell layer of the mat promoted angiogenesis in human umbilical vascular endothelial cells (HUVECs), whereas ZnO in the fibrous core layer harvested bioenergy and converted it into electrical energy to enhance osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs), and both modalities synergistically promoted osteogenesis and angiogenesis. Furthermore, optimal bone regeneration was achieved in a model of critical bone defects in the rat mandible. This osteogenesis-promoting effect was induced by electrical stimulation via activation of the calcium signaling pathway. This multifunctional mat coupling piezoelectric stimulation and atorvastatin promotes angiogenesis and bone regeneration, and shows great potential in the treatment of large bone defects.

Electrical Stimulating Redox Membrane Incorporated with PVA/Gelatin Nanofiber for Diabetic Wound Healing

Chronic wounds adversely affect the quality of life. Although electrical stimulation has been utilized to treat chronic wounds, there are still limitations to practicing it due to the complicated power system. Herein, an electrostimulating membrane incorporated with electrospun nanofiber (M-sheet) to treat diabetic wounds is developed. Through the screen printing method, the various alternate patterns of both Zn and AgCl on a polyurethane substrate, generating redox-mediated electrical fields are introduced. The antibacterial ability of the patterned membrane against both E. coli and S. aureus is confirmed. Furthermore, the poly(vinyl alcohol) (PVA)/gelatin electrospun fiber is incorporated into the patterned membrane to enhance biocompatibility and maintain the wet condition in the wound environment. The M-sheet can improve cell proliferation and migration in vitro and has an immune regulatory effect by inducing the polarization of macrophage to the M2 phenotype. Finally, when applied to a diabetic skin wound model, the M-sheet displays an accelerated wound healing rate and enhances re-epithelialization, collagen synthesis, and angiogenesis. It suggests that the M-sheet is a simple and portable system for the spontaneous generation of electrical stimulation and has great potential to be used in the practical wound and other tissue engineering applications.

Rationally Improved Surface Charge Density of Triboelectric Nanogenerator with TiO2-MXene/Polystyrene Nanofiber Charge Trapping Layer for Biomechanical Sensing and Wound Healing Application

Triboelectric nanogenerators (TENGs) have become reliable green energy harvesters by converting biomechanical motions into electricity. However, the inevitable charge leakage and poor electric field (EF) of conventional TENG result in inferior tribo-charge density on the active layer. In this paper, TiO2-MXene incorporated polystyrene (PS) nanofiber membrane (PTMx NFM) charge trapping interlayer is introduced into single electrode mode TENG (S-TENG) to prevent electron loss at the electrode interface. Surprisingly, this charge-trapping mechanism augments the surface charge density and electric output performance of TENGs. Polyvinylidene difluoride (PVDF) mixed polyurethane (PU) NFM is used as tribo-active layer, which improves the crystallinity and mechanical property of PVDF to prevent delamination during long cycle tests. Herein, the effect of this double-layer capacitive model is explained experimentally and theoretically. With optimization of the PTMx interlayer thickness, S-TENG exhibits a maximum open-circuit voltage of (280 V), short-circuit current of (20 µA) transfer charge of (120 nC), and power density of (25.2 µW cm-2). Then, this energy is utilized to charge electrical appliances. In addition, the influence of AC/DC EF simulation in wound healing management (vitro L929 cell migration, vivo tissue regeneration) is also investigated by changing the polarity of trans-epithelial potential (TEP) distribution in the wounded area.

Mesoporous Silicon with Strontium-Powered Poly(Lactic-Co-Glycolic acid)/Gelatin-Based Dressings Facilitate Skin Tissue Repair

Purpose

Functional inorganic nanomaterials (NMs) are widely exploited as bioactive materials and drug depots. The lack of a stable form of application of NMs at the site of skin injury, may impede the removal of the debridement, elevate pH, induce tissue toxicity, and limit their use in skin repair. This necessitates the advent of innovative wound dressings that overcome the above limitations. The overarching objective of this study was to exploit strontium-doped mesoporous silicon particles (PSiSr) to impart multifunctionality to poly(lactic-co-glycolic acid)/gelatin (PG)-based fibrous dressings (PG@PSiSr) for excisional wound management.

Methods

Mesoporous silicon particles (PSi) and PSiSr were synthesized using a chemo-synthetic approach. Both PSi and PSiSr were incorporated into PG fibers using electrospinning. A series of structure, morphology, pore size distribution, and cumulative pH studies on the PG@PSi and PG@PSiSr membranes were performed. Cytocompatibility, hemocompatibility, transwell migration, scratch wound healing, and delineated angiogenic properties of these composite dressings were tested in vitro. The biocompatibility of composite dressings in vivo was assessed by a subcutaneous implantation model of rats, while their potential for wound healing was discerned by implantation in a full-thickness excisional defect model of rats.

Results

The PG@PSiSr membranes can afford the sustained release of silicon ions (Si4+) and strontium ions (Sr2+) for up to 192 h as well as remarkably promote human umbilical vein endothelial cells (HUVECs) and NIH-3T3 fibroblasts migration. The PG@PSiSr membranes also showed better cytocompatibility, hemocompatibility, and significant formation of tubule-like networks of HUVECs in vitro. Moreover, PG@PSiSr membranes also facilitated the infiltration of host cells and promoted the deposition of collagen while reducing the accumulation of inflammatory cells in a subcutaneous implantation model in rats as assessed for up to day 14. Further evaluation of membranes transplanted in a full-thickness excisional wound model in rats showed rapid wound closure (PG@SiSr vs control, 96.1% vs 71.7%), re-epithelialization, and less inflammatory response alongside skin appendages formation (eg, blood vessels, glands, hair follicles, etc.).

Conclusion

To sum up, we successfully fabricated PSiSr particles and prepared PG@PSiSr dressings using electrospinning. The PSiSr-mediated release of therapeutic ions, such as Si4+ and Sr2+, may improve the functionality of PLGA/Gel dressings for an effective wound repair, which may also have implications for the other soft tissue repair disciplines.

Aqueous-Aqueous Triboelectric Nanogenerators Empowered Multifunctional Wound Healing System with Intensified Current Output for Accelerating Infected Wound Repair

Triboelectric nanogenerators (TENGs) have emerged as promising devices for generating self-powered therapeutic electrical stimulation over multiple aspects of wound healing. However, the challenge of achieving full 100% contact in conventional TENGs presents a substantial hurdle in the quest for higher current output, which is crucial for further improving healing efficacy. Here, a novel multifunctional wound healing system is presented by integrating the aqueous-aqueous triboelectric nanogenerators (A-A TENGs) with a functionalized conductive hydrogel, aimed at advancing infected wound therapy. The A-A TENGs are founded on a principle of 100% contact interface and efficient post-contact separation of the immiscible interface within the aqueous two-phase system (ATPS), enhancing charge transfer and subsequently increasing current performance. Leveraging this intensified current output, this system demonstrates efficient therapeutic efficacies over infected wounds both in vitro and in vivo, including stimulating fibroblast migration and proliferation, boosting angiogenesis, enhancing collagen deposition, eradicating bacteria, and reducing inflammatory cells. Moreover, the conductive hydrogel ensures the uniformity and integrity of the electric field covering the wound site, and exhibits multiple synergistic therapeutic effects. With the capability to realize accelerated wound healing, the developed "A-A TENGs empowered multifunctional wound healing system" presenting an excellent prospect in clinical wound therapy.

Composite Aerogel Scaffolds Containing Flexible Silica Nanofiber and Tricalcium Phosphate Enable Skin Regeneration

Poor hemostatic ability and less vascularization at the injury site could hinder wound healing as well as adversely affect the quality of life (QOL). An ideal wound dressing should exhibit certain characteristics: (a) good hemostatic ability, (b) rapid wound healing, and (c) skin appendage formation. This necessitates the advent of innovative dressings to facilitate skin regeneration. Therapeutic ions, such as silicon ions (Si4+) and calcium ions (Ca2+), have been shown to assist in wound repair. The Si4+ released from silica (SiO2) can upregulate the expression of proteins, including the vascular endothelial growth factor (VEGF) and alpha smooth muscle actin (α-SMA), which is conducive to vascularization; Ca2+ released from tricalcium phosphate (TCP) can promote the coagulation alongside upregulating the expression of cell migration and cell differentiation related proteins, thereby facilitating the wound repair. The overarching objective of this study was to exploit short SiO2 nanofibers along with the TCP to prepare TCPx@SSF aerogels and assess their wound healing ability. Short SiO2 nanofibers were prepared by electrospinning and blended with varying proportions of TCP to afford TCPx@SSF aerogel scaffolds. The TCPx@SSF aerogels exhibited good cytocompatibility in a subcutaneous implantation model and manifested a rapid hemostatic effect (hemostatic time 75 s) in a liver trauma model in the rabbit. These aerogel scaffolds also promoted skin regeneration and exhibited rapid wound closure, epithelial tissue regeneration, and collagen deposition. Taken together, TCPx@SSF aerogels may be valuable for wound healing.

Permeable Bioelectronics toward Biointegrated Systems

Bioelectronics integrates electronics with biological organs, sustaining the natural functions of the organs. Organs dynamically interact with the external environment, managing internal equilibrium and responding to external stimuli. These interactions are crucial for maintaining homeostasis. Additionally, biological organs possess a soft and stretchable nature; encountering objects with differing properties can disrupt their function. Therefore, when electronic devices come into contact with biological objects, the permeability of these devices, enabling interactions and substance exchanges with the external environment, and the mechanical compliance are crucial for maintaining the inherent functionality of biological organs. This review discusses recent advancements in soft and permeable bioelectronics, emphasizing materials, structures, and a wide range of applications. The review also addresses current challenges and potential solutions, providing insights into the integration of electronics with biological organs.

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.

Methacrylated gelatin and platelet-rich plasma based hydrogels promote regeneration of critical-sized bone defects

Physiological repair of large-sized bone defects requires instructive scaffolds with appropriate mechanical properties, biocompatibility, biodegradability, vasculogenic ability and osteo-inductivity. The objective of this study was to fabricate in situ injectable hydrogels using platelet-rich plasma (PRP)-loaded gelatin methacrylate (GM) and employ them for the regeneration of large-sized bone defects. We performed various biological assays as well as assessed the mechanical properties of GM@PRP hydrogels alongside evaluating the release kinetics of growth factors (GFs) from hydrogels. The GM@PRP hydrogels manifested sufficient mechanical properties to support the filling of the tissue defects. For biofunction assay, the GM@PRP hydrogels significantly improved cell migration and angiogenesis. Especially, transcriptome RNA sequencing of human umbilical vein endothelial cells and bone marrow-derived stem cells were performed to delineate vascularization and biomineralization abilities of GM@PRP hydrogels. The GM@PRP hydrogels were subcutaneously implanted in rats for up to 4 weeks for preliminary biocompatibility followed by their transplantation into a tibial defect model for up to 8 weeks in rats. Tibial defects treated with GM@PRP hydrogels manifested significant bone regeneration as well as angiogenesis, biomineralization, and collagen deposition. Based on the biocompatibility and biological function of GM@PRP hydrogels, a new strategy is provided for the regenerative repair of large-size bone defects.

Natural Polysaccharide Film-Based Triboelectric Sensor for Fruit Transportation Collision Monitoring

Transportation-induced damage to fresh produce is a big challenge in logistics. Current acceleration and pressure sensors for collision monitoring face issues of power dependency, high cost, and environmental concerns. Here, a self-powered and environmentally friendly triboelectric sensor has been developed to monitor fruit collisions in transportation packaging. Microcrystalline cellulose/chitosan and sodium alginate films were prepared as positive and negative tribo-layers to assemble a natural polysaccharide film-based triboelectric nanogenerator (NP-TENG). The NP-TENG's electrical output was proportional to the structure parameters (contact surface roughness and separation gap of the tribo-layers) and the vibration factors (force and frequency) and exhibited excellent stability and durability (over 100,000 cycles under 13 N at 10 Hz). The high mechanical-to-electrical conversion efficiency (instantaneous areal power density of 9.6 mW/m2) and force sensitivity (2.2 V/N) enabled the NP-TENG to be a potential sensor for monitoring fresh produce collisions in packaging during logistics. Transportation simulation measurements of kiwifruits verified that the sensor's electrical outputs increased with the vibration frequency and stacking layer while varying at different packaging locations. This study suggests that the NP-TENG can effectively monitor collision damage during fruit transportation, providing new insights into developing intelligent food packaging systems to reduce postharvest supply chain losses.

Wearable Magnetoelectric Stimulation for Chronic Wound Healing by Electrospun CoFe2O4@CTAB/PVDF Dressings

Magnetoelectric stimulation is a promising therapy for various disorders due to its high efficacy and safety. To explore its potential in chronic skin wound treatment, we developed a magnetoelectric dressing, CFO@CTAB/PVDF (CCP), by electrospinning cetyltrimethylammonium bromide-modified CoFe2O4 (CFO) particles with polyvinylidene fluoride. Cetyltrimethylammonium bromide (CTAB) serves as a dispersion surfactant for CFO, with its quaternary ammonium cations imparting antibacterial and hydrophilic properties to the dressing. Electrospinning polarizes polyvinylidene fluoride (PVDF) molecules and forms a fibrous membrane with flexibility and breathability. With a wearable electromagnetic induction device, a dynamic magnetic field is established to induce magnetostrictive deformation of CFO nanoparticles. Consequently, a piezoelectric potential is generated on the surface of PVDF nanofibers to enhance the endogenous electrical field in the wound, achieving a cascade coupling of electric-magnetic-mechanical-electric effects. Bacteria and cell cultures show that 2% CTAB effectively balances antibacterial property and fibroblast activity. Under dynamic magnetoelectric stimulation, the CCP dressing demonstrates significant upregulation of TGF-β, FGF, and VEGF, promoting L929 cell adhesion and proliferation. Moreover, it facilitates the healing of diabetic rat skin wounds infected with Staphylococcus aureus within 2 weeks. Histological and molecular biology evaluations confirm the anti-inflammatory effect of CTAB and the accelerated formation of collagen and vessel by electrical stimulation. This work provides insights into the application of magnetoelectric stimulation in the healing of chronic wounds.

Next-generation of smart dressings: Integrating multiplexed sensors and theranostic functions

Non-healing wounds represent a significant burden for healthcare systems and society, giving rise to severe economic and human issues. Currently, the use of dressings and visual assessment represent the primary and standard care for wounds. Conventional dressings, like cotton gauze, provide only passive physical protection. Besides, they end up paradoxically hampering the wound-healing process by producing tissue damage and pain when removed during routine check-ups. In response to these limitations, researchers, engineers, and technologists are developing innovative dressings that incorporate advanced diagnostic and therapeutic functionalities, coined as "smart dressings". Now, the maturation of smart dressing is bringing them closer to real-life applications, leading to an exciting new generation of these devices. The next generation of smart dressings is capable of monitoring in real-time multiple biomarkers while including pro-healing capabilities in a single platform. Such multiplexed and theranostic smart dressings are expected to offer a timely biomarker-directed diagnosis of non-healing wounds while enabling rapid, automated, and personalized treatments of infection and chronicity. Herein, we provide an insightful overview of these advantageous devices, delving into the diverse spectrum of possible engineering strategies. This encompasses the use of electrochemical and optical platforms with diverse multiplexing architectures, such as multi-zone sensing arrays and multi-layered devices. Open or closed-loop theranostic mechanisms using various stimuli-responsive materials that could be internally or externally controlled are also included. Finally, a critical discussion on the main challenges and future directions of smart dressings is also offered.

Cotton fiber-based dressings with wireless electrical stimulation and antibacterial activity for wound repair

Although cotton dressing is one of the most commonly used wound management materials, it lacks antimicrobial and healing-promoting activity. This work developed a multilayer electroactive composite cotton dressing (Ag/Zn@Cotton/Paraffin) with exudate-activated electrical stimulation and antibacterial activity by the green and sustainable magnetron-sputtering and spraying methods. The inner hydrophilic layer of the cotton dressing was magnetron sputtered with silver/zinc galvanic couple arrays (Ag/Zn), which can be activated by wound exudate, generating an electrical stimulation (ES) into the wound. The Ag/Zn@Cotton showed efficient antibacterial activities against S. aureus and E. coli. Meanwhile, the paraffin-sprayed outer surface showed excellent antibacterial adhesion rates for S. aureus (99.82 %) and E. coli (97.92 %). The in vitro cell experiments showed that the ES generated by Ag/Zn@Cotton/Paraffin increased the migration of fibroblasts, and the in vivo mouse model indicated that the Ag/Zn@Cotton/Paraffin could enhance wound healing via re-epithelialization, inflammatory inhibition, collagen deposition, and angiogenesis. MTT method and live/dead staining showed that Ag/Zn@Cotton/Paraffin had no significant cytotoxic effects. This work may shed some light on designing and fabricating multi-functional electroactive composited dressings based on traditional biomedical textiles.

Electrospun fibers for the treatment of skin diseases

Skin diseases are among the most common diseases in the global population and with the growth of the aging population, they represent an increasing burden to healthcare systems worldwide. Even though they are rarely life-threatening, the suffering for those affected is high due to the visibility and physical discomfort related to these diseases. Typical symptoms of skin diseases include an inflamed, swollen or itchy skin, and therefore, there is a high demand for effective therapy options. In recent years, electrospinning has attracted considerable interest in the field of drug delivery. The technique allows producing multifunctional drug-loaded fibrous patches from various natural and synthetic polymers with fiber diameters in the nano- and micrometer range, suitable for the treatment of a wide variety of skin diseases. The great potential of electrospun fiber patches not only lies in their tunable drug release properties and the possibility to entrap a variety of therapeutic compounds, but they also provide physical and mechanical protection to the impaired skin area, exhibit a high surface area, allow gas exchange, absorb exudate due to their porous structure and are cytocompatible and biodegradable. In the case of wound healing, cell adhesion is promoted due to the resemblance of the electrospun fibers to the structure of the native extracellular matrix. This review gives an overview of the potential applications of electrospun fibers in skin therapy. In addition to the treatment of bacterial, diabetic and burn wounds, focus is placed on inflammatory diseases such as atopic dermatitis and psoriasis, and therapeutic options for the treatment of skin cancer, acne vulgaris and herpes labialis are discussed. While we aim to emphasize the great potential of electrospun fiber patches for the treatment of skin diseases with this review paper, we also highlight challenges and limitations of current research in the field.

Piezoelectric and Triboelectric Nanogenerators for Enhanced Wound Healing

Wound healing is a highly orchestrated biological process characterized by sequential phases involving inflammation, proliferation, and tissue remodeling, and the role of endogenous electrical signals in regulating these phases has been highlighted. Recently, external electrostimulation has been shown to enhance these processes by promoting cell migration, extracellular matrix formation, and growth factor release while suppressing pro-inflammatory signals and reducing the risk of infection. Among the innovative approaches, piezoelectric and triboelectric nanogenerators have emerged as the next generation of flexible and wireless electronics designed for energy harvesting and efficiently converting mechanical energy into electrical power. In this review, we discuss recent advances in the emerging field of nanogenerators for harnessing electrical stimulation to accelerate wound healing. We elucidate the fundamental mechanisms of wound healing and relevant bioelectric physiology, as well as the principles underlying each nanogenerator technology, and review their preclinical applications. In addition, we address the prominent challenges and outline the future prospects for this emerging era of electrical wound-healing devices.

Sequential Anti-Infection and Proangiogenesis of DMOG@ZIF-8/Gelatin-PCL Electrospinning Dressing for Chronic Wound Healing

Bacterial infection and insufficient neovascularization are two major obstacles to the healing of chronic wounds. Here, we present an antibacterial and proangiogenic dressing by encapsulating dimethyloxalylglycine (DMOG) in zeolitic imidazolate framework-8 (ZIF-8) and electrospinning it with gelatin-polycaprolactone (Gel-PCL). As Gel-PCL nanofibers degrade, ZIF-8 nanoparticles decompose, sequentially releasing bactericidal zinc ions and angiogenic DMOG molecules. This cascade process matches the wound-healing stages, ensuring suitable bioavailability and an effective duration of the active components while minimizing their side effects. In vitro, zinc ions released from the dressing (2.5% DMOG@ZIF-8) can eliminate over 90% of Escherichia coli and Staphylococcus aureus without compromising fibroblast cell proliferation and adhesion. In vivo, the dressing can heal skin wounds in Staphylococcus aureus-infected diabetic rats within 2 weeks, facilitated by the DMOG molecules discharged from ZIF-8 (loading rate 21.3%). Immunohistochemical analysis confirmed the regulated expression of factors by zinc ions and DMOG molecules. This work provides new insights into the design of multifunctional dressings for the treatment of chronic wounds.

Recent Advances in Functional Fiber-Based Wearable Triboelectric Nanogenerators

The quality of human life has improved thanks to the rapid development of wearable electronics. Previously, bulk structures were usually selected for the fabrication of high performance electronics, but these are not suitable for wearable electronics due to mobility limitations and comfortability. Fibrous material-based triboelectric nanogenerators (TENGs) can provide power to wearable electronics due to their advantages such as light weight, flexibility, stretchability, wearability, etc. In this work, various fiber materials, multiple fabrication methods, and fundamentals of TENGs are described. Moreover, recent advances in functional fiber-based wearable TENGs are introduced. Furthermore, the challenges to functional fiber-based TENGs are discussed, and possible solutions are suggested. Finally, the use of TENGs in hybrid devices is introduced for a broader introduction of fiber-based energy harvesting technologies.

In Situ Polymerization of Methylene Blue on Bacterial Cellulose for Photodynamic/Photoelectricity Synergistic Inhibition of Bacterial Biofilm Formation

In the context of long-term antimicrobial treatment, the emergence of bacterial resistance poses a significant challenge. Therefore, there is a pressing need to develop novel antimicrobial materials and methods that can effectively and safely combat microbial infections. This study focuses on the synthesis of bacterial cellulose-polymethylene blue (BC-PMB) with integrated photodynamic and photoelectric antimicrobial properties. The polymerization of methyl blue (MB) onto bacterial celluloses (BC) was achieved, and through comprehensive computational analyses using density functional theory (DFT) and molecular dynamics simulations, it was confirmed that this polymerization greatly enhanced the binding efficiency between methylene blue and BC. Additionally, polymethylene blue (PMB) exhibited superior photoexcitation efficiency and conductivity compared to its precursor. When BC-PMB was exposed to a 30 mW 660 nm light source for 30 min, the material demonstrated a remarkable antimicrobial efficacy of 93.99% against Escherichia coli and 98.58% against Staphylococcus aureus. Furthermore, the synergistic effect of photodynamic and photoelectric antimicrobial mechanisms exhibited long-term inhibitory capabilities against bacterial biofilms.

Recent Progress of Photothermal Therapy Based on Conjugated Nanomaterials in Combating Microbial Infections

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to the choice of photothermal agent. Conjugated nanomaterials are potential candidates for photothermal agents because of their easy modification, excellent photothermal conversion efficiency, good photostability, and biodegradability. In this paper, the application of photothermal agents based on conjugated nanomaterials in photothermal antimicrobial treatment is reviewed, including conjugated small molecules, conjugated oligomers, conjugated polymers, and pseudo-conjugated polymers. At the same time, the application of conjugated nanomaterials in the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is briefly introduced. Finally, the research status, limitations, and prospects of photothermal therapy using conjugated nanomaterials as photothermal agents are discussed.