Antibacterial adhesive self-healing hydrogels to promote diabetic wound healing

Quaternary ammonium grafted chitosan hydrogel with enhanced antibacterial performance as tannin acid and deferoxamine carrier to promote diabetic wound healing

The delay of diabetic wound healing puts a huge burden on the society. The key factors hindering wound healing include bacterial infection, unresolved inflammation and poorly generated blood vessels. In this paper, glycidyl trimethyl ammonium chloride (GTA) was grafted to chitosan (CS) to obtain quaternary ammonium grafted chitosan (QCS) with enhanced antibacterial performance, and then cross-linked by dialdehyde terminated poly(ethylene oxide) (PEO DA) to construct QCS/PEO DA hydrogel with tissue adhesion, biodegradation and self-healing properties. The QCS/PEO DA hydrogel is loaded with tannin acid (TA) and deferoxamine (DFO) to enhance antioxidant property and angiogenesis. At the same time, the TA and DFO loaded TA@DFO/hydrogel preserved the biocompatibility and biodegradability of chitosan. Moreover, the multifunctional hydrogel behaved excellent hemostatic properties in mice model and significantly promoted the healing efficacy of diabetic wounds. Overall, the TA@DFO/hydrogel is promising anti-infection dressing material for diabetic wound healing.

Emerging biomedical technologies for scarless wound healing

Complete wound healing without scar formation has attracted increasing attention, prompting the development of various strategies to address this challenge. In clinical settings, there is a growing preference for emerging biomedical technologies that effectively manage fibrosis following skin injury, as they provide high efficacy, cost-effectiveness, and minimal side effects compared to invasive and costly surgical techniques. This review gives an overview of the latest developments in advanced biomedical technologies for scarless wound management. We first introduce the wound healing process and key mechanisms involved in scar formation. Subsequently, we explore common strategies for wound treatment, including their fabrication methods, superior performance and the latest research developments in this field. We then shift our focus to emerging biomedical technologies for scarless wound healing, detailing the mechanism of action, unique properties, and advanced practical applications of various biomedical technology-based therapies, such as cell therapy, drug therapy, biomaterial therapy, and synergistic therapy. Finally, we critically assess the shortcomings and potential applications of these biomedical technologies and therapeutic methods in the realm of scar treatment.

Polyvinyl alcohol/PEDOT:PSS with Fe3+/amylopectin enabled highly tough, anti-freezing and healable hydrogels for multifunctional wearable sensors

In recent years, hydrogel-based flexible sensors have garnered increasing attention in research. Ionic hydrogels, enriched with large amounts of ionic liquids, exhibit electrical conductivity, excellent electrochemical stability, anti-freezing, and antimicrobial properties. However, most ionic hydrogels suffer from poor mechanical properties, limiting their adaptability to more complex application scenarios. Integrating conductive polymers into hydrogels leads to desirable features such as increased specific surface area, soft and biocompatible interfaces, and high electrolyte permeability. In this study, we successfully prepared Fe3+/Ap@PVA/PEDOT double-network hydrogel. Utilizing polyvinyl alcohol (PVA) as the primary matrix, we introduced PEDOT:PSS and FeCl3 to confer conductivity to the hydrogel. The incorporation of amylopectin (Ap) further enhanced mechanical performance. The resulted hydrogel sensor exhibits outstanding mechanical properties, allowing for stretching up to 347 % and withstanding a tensile force of 505 kPa. In addition, it exhibits excellent antifreeze properties (can work at -30 °C), healability, water retention, and high sensitivity to stretching (GF = 4.72 at a 200 % strain ratio), compression (GF = 2.97 at a 12 % compressive ratio), and temperature (TCR = 2.46). These remarkable properties of the hydrogel make it possible in applications such as human motion monitoring, handwriting recognition, and temperature sensing.

Hydroxypropyl methylcellulose reinforced bilayer hydrogel dressings containing L-arginine-modified polyoxometalate nanoclusters to promote healing of chronic diabetic wounds

Diabetes-related slow healing of wounds is primarily driven by bacterial infections and angiogenesis disorder and presents a substantial hurdle in clinical treatment. To solve the above problems, an advanced multifunctional hydrogel system based on natural polymer was created here to facilitate wound healing in patients with chronic diabetes. The prepared dressing was composed of an outer hydrogel containing polyvinyl alcohol and hydroxypropyl methyl cellulose in dimethyl sulfoxide and water as binary solvents, and an inner hydrogel containing chitosan quaternary ammonium salt, flaxseed gum, and polyvinyl alcohol. Thus, a polysaccharide based bilayer hydrogel (BH) with superior mechanical strength and biocompatibility was created. This bilayer hydrogel could easily bind to dynamic tissue surfaces, thereby generating a protective barrier. Meanwhile, L-arginine-modified polyoxometalate (POM@L-Arg) nanoclusters were loaded in the inner hydrogel. They released NO when stimulated by the peroxide microenvironment of diabetic wounds. NO as a signal molecule regulated vascular tension and promoted cell proliferation and migration. Additionally, because of the synergistic effect of NO and the chitosan quaternary ammonium salt, the hydrogel system exhibited excellent antibacterial performance. The NO released reduced the levels of proinflammatory factors IL-6 and TNF-α in the diabetic wounds, which thus accelerated wound healing. In short, BH + POM@L-Arg is expected to serve as an ideal wound dressing as it exerts a good promotion effect on diabetes-related wound healing.

Composite antibacterial hydrogels based on two natural products pullulan and ε-poly-l-lysine for burn wound healing

Antibacterial hydrogels as burn wound dressings are capable of efficaciously defending against bacterial infection and accelerating burn wound healing. Thus far, a large plethora of antibacterial hydrogels have adopted numerous components and intricate preparation processes, yet restricting their practical industrialization applications. Simple and effective preparation methods of antibacterial hydrogels are hence urgently needed. Herein, an easy but efficacious strategy with the employment of two natural products pullulan and ε-poly-l-lysine (ε-PL) was designed to fabricate composite antibacterial hydrogels for burn wound healing for the first time. The hydrogel crosslinking networks were formed through amidation reactions between carboxylated pullulan derivative (CP) and ε-poly-l-lysine hydrochloride (ε-PL·HCl). The resulting hydrogels possessed high transparency, porous structures, tunable gelation time and gel content, relatively low swelling ratios, appropriate self-degradability, proper mechanical properties, strong in vitro bacteriostatic activities, non-cytotoxicity, capacities of facilitating cell migration and excellent hemocompatibility. In the infected burn model of mice, the hydrogels were observed to display prominent in vivo antibacterial activities and enable the acceleration of burn wound healing. We opine the simply and effectively prepared antibacterial hydrogels as promising dressings for burn wound recovery have broad industrialization prospects.

Using polycaprolactone and sodium alginate to prepare self-pumping/super-absorbent/transportable drug dressings for stage 3-4 pressure ulcer treatment

Pressure ulcer dressings with different functions can enhance wound healing ability to varying degrees; however, pressure ulcer dressings that integrate various functions and break the resistance of bacteria to traditional antibiotics have not been widely studied. We proposed a self-pumping/super-absorbent/transportable drug dressing (PLD-SLD), polycaprolactone (PCL)/sodium alginate (SA) was used to load platelet-derived growth factor (PDGF) and lidocaine hydrochloride (LID) by Janus electrospinning and self-assembly technology, and Ɛ-polylysine was used as a biological bacteriostatic agent to prepare a multi-layer dressing. SEM showed that the dressing had a fluffy structure. The dressing can pump the exudate to the SA layer away from the skin. The swelling ratio reached 1378.667 ± 44.752 %. Coagulate blood in 5 min. On the 8th day, the unclosed area rate of the PLD-SLD dressing group was 16.112 ± 0.088 % lower than that of the model group. Importantly, the dressing can induce the expression of CD31, VEGF, α-SMA, and reduce the expression of CD68, thereby giving priority to wound healing. There was no scar formation after healing. In this study, a new dressing preparation method was proposed for the problems of exudate management, infection control, pain relief and healing promotion of stage 3-4 pressure ulcer healing.

In-situ hydrogen-generating injectable short fibers for osteoarthritis treatment by alleviating oxidative stress

Hydrogen (H₂) has great potential in the treatment of osteoarthritis, but its rapid diffusion and short retention time make it difficult to exert stable therapeutic effects. This study developed a short-fiber injectable material that can continuously generate hydrogen in situ to eliminate reactive oxygen species (ROS), alleviate oxidative stress and inflammation, and promote tissue repair. We prepared H-Si nanosheets with high hydrogen generation efficiency using a wet chemical exfoliation method and combined them with GelMA short fibers via electrospinning technology, achieving the in situ delivery of H-Si nanosheets and regulated hydrogen generation rate through the encapsulation and degradation of GelMA, ultimately achieving continuous and controlled hydrogen supply and stable therapeutic effects for osteoarthritis. In vitro and in vivo experiments confirmed the safety and efficacy of this material. The results showed that the material could continuously and efficiently generate hydrogen in simulated physiological environments (100 mg of material could generate 8.6 % hydrogen), effectively eliminate cellular reactive oxygen species (ROS positive rate reduced by 85.89 %), reduce cellular senescence and apoptosis (cell death rate decreased by 52 %, SA-βgal expression decreased by 78.3 %), promote normal chondrocyte function (Col II expression increased by 67.4 %, Ki67 expression increased by 87.5 %), and improve osteoarthritis in rats (OARSI score increased by 216 %). The in situ hydrogen generation and control system designed in this study provides a new method for the hydrogen's local and stable treatment of osteoarthritis. STATEMENT OF SIGNIFICANCE: Hydrogen (H₂) has great potential in the treatment of osteoarthritis by alleviating oxidative stress, but its rapid diffusion and short retention time make it difficult to exert stable therapeutic effects. This study introduces an innovative injectable material combining H-Si nanosheets and GelMA short fibers to address this issue. By enabling continuous in situ hydrogen generation, this material effectively eliminates reactive oxygen species, reduces oxidative stress and inflammation, and promotes tissue repair. In vitro and in vivo experiments demonstrate its high hydrogen generation efficiency, safety, and therapeutic efficacy, offering a promising new approach for osteoarthritis management.

Formulation and evaluation of n-acetyl cysteine loaded bi-polymeric physically crosslinked hydrogel with antibacterial and antioxidant activity for diabetic wound dressing

Diabetic wounds have become a serious global health concern, with a growing number of patients each year. Diabetic altered wound healing physiology, as well as resulting complications, make therapy difficult. Hence, diabetic wound healing necessitates a multidisciplinary strategy. This study focused on the formulation, statistical optimization, ex vivo, and in vitro evaluation of a diabetic wound healing by n-acetyl cysteine (NAC) loaded hydrogel. The objective of the study is to formulate n-acetyl loaded hydrogel with different ratio (1:1, 1:2, 1:3, 2:1) of sodium alginate and guar gum. The antibacterial and antifungal assessment against the viability of Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S.aureus) and Candida albicans (C. albicans) was conducted after determining the in vitro drug release profile. The results of the experiment demonstrated that the formulation F3 was an optimal formulation on triplicate measurement with a pH of 6.2 ± 0.168, and a density of 1.026 ± 0.21. In vitro cell line study exhibited F3 has potential role in cell adhesion and proliferation might be beneficial to tissue regeneration and wound healing. The results imply that F3 may be helpful for the quick healing of diabetic wounds by promoting angiogenesis and also by scavenging free oxygen radicals.

Hericium erinaceus β-glucan/tannic acid hydrogels based on physical cross-linking and hydrogen bonding strategies for accelerating wound healing

The majority of natural fungal β-glucans exhibit diverse biological functionalities, such as immunomodulation and anti-inflammatory effects, attributed to their distinctive helix or highly branched conformation This study utilized β-glucan with helix conformation and high-viscosity extracted from Hericium erinaceus, employing freeze-thaw and solvent exchange strategies to induce multiple hydrogen bonding between molecules, thereby initiating the self-assembly process of β-glucan from random coil to stable helix conformation without chemical modifications. Subsequently, the natural bioactive compound tannic acid was introduced through physical entanglement, imparting exceptional antioxidant properties to the hydrogel. The HEBG/TA hydrogel exhibited injectable properties, appropriate mechanical characteristics, degradability, temperature-responsive tannic acid release, antioxidant activity, and hemostatic potential. In vivo experiments using skin full-thickness defect and deep second-degree burn wound models demonstrated significant therapeutic efficacy, including neovascularization, and tissue regeneration. Moreover, the HEBG/TA hydrogel demonstrated its ability to regulate cytokines by effectively inhibiting the production of inflammatory mediators (TNF-α, IL-6), while simultaneously enhancing the expression of cell proliferation factor KI-67 and markers associated with angiogenesis such as CD31 and α-SMA. This study highlights the potential of combining natural β-glucan with bioactive molecules for skin repair.

Development of gelatin-methacryloyl composite carriers for bone morphogenetic Protein-2 delivery: A potential strategy for spinal fusion

To reduce the risk of nonunion after spinal fusion surgery, the in situ transplantation of bone marrow mesenchymal stem cells (BMSCs) induced toward osteogenic differentiation by bone morphogenetic protein-2 (BMP2) has been proven effective. However, the current biological agents used for transplantation have limitations, such as a short half-life and low bioavailability. To address this, our study utilized a safe and effective gelatin-methacryloyl (GelMA) as a carrier for BMP2. In vitro, experiments were conducted to observe the ability of this composite vehicle to induce osteogenic differentiation of BMSCs. The results showed that the GelMA hydrogel, with its critical properties and controlled release performance of BMP2, exhibited a slow release of BMP2 over 30 days. Moreover, the GelMA hydrogel not only enhanced the proliferation activity of BMSCs but also significantly promoted their osteogenic differentiation ability, surpassing the BMP2 effects. To investigate the potential of the GelMA-BMP2 composite vehicle, a rabbit model was employed to explore its ability to induce in situ intervertebral fusion by BMSCs. Transplantation experiments in rabbits demonstrated the effective induction of intervertebral bone fusion by the GelMA-BMP2-BMSC composite vehicle. In conclusion, the GelMA-BMP2-BMSC composite vehicle shows promising prospects in preclinical translational therapy for spinal intervertebral fusion. It addresses the limitations of current biological agents and offers a controlled release of BMP2, enhancing the proliferation and osteogenic differentiation of BMSCs.

A wearable iontophoresis enables dual-responsive transdermal delivery for atopic dermatitis treatment

Atopic dermatitis is a chronic, inflammation skin disease that remains a major public health challenge. The current drug-loading hydrogel dressings offer numerous benefits with enhanced loading capacity and a moist-rich environment. However, their development is still limited by the accessibility of a suitable driven source outside the clinical environment for precise control over transdermal delivery kinetics. Here, we prepare a sulfonated poly(3,4-ethylenedioxythiophene) (PEDOT) polyelectrolyte hydrogel drug reservoir that responds to different stimuli-both endogenous cue (body temperature) and exogenous cue (electrical stimulation), for wearable on-demand transdermal delivery with enhanced efficacy. Functioned as both the drug reservoir and cathode in a Zn battery-powered iontophoresis patch, this dual-responsive hydrogel achieves high drug release efficiency (68.4 %) at 37 °C. Evaluation in hairless mouse skin demonstrates the efficacy of this technology by facilitating transdermal transport of 12.2 μg cm-2 dexamethasone phosphate when discharged with a 103 Ω external resistor for 3 h. The Zn battery-driven iontophoresis results in an effective treatment of atopic dermatitis, displaying reductions in epidermal thickness, mast cell infiltration inhibition, and a decrease in IgE levels. This work provides a new treatment modality for chronic epidermal diseases that require precise drug delivery in a non-invasive way.

Constructing a highly efficient multifunctional carbon quantum dot platform for the treatment of infectious wounds

Antibiotic resistance poses a huge threat to public health, which has increased the difficulty and transmission of disease treatment, as well as the burden and cost of medical institutions. In response to the current problems and challenges in inflammation control and treatment of bacterial infected wounds, inspired by antibacterial mechanisms based on active elements such as N, S, Cu and tannic acid (TA), a highly efficient multifunctional carbon quantum dot platform was proposed in this study and constructed through their special assembly in a solvothermal reaction system for the treatment of infected wounds. By introducing active elements such as N, S and Cu, this carbon quantum dot platform is endowed with antibacterial properties, while also achieving good angiogenesis promoting performance through the use of ion Cu. Meanwhile, the good antioxidant activity of TA (one of the precursors used) enables this platform to have better immunomodulatory performance in vivo. The research results on the treatment of bacterial infection models indicate that the multifunctional carbon quantum dots obtained can accelerate the healing of infected wounds by inhibiting bacterial infection, regulating immunoreaction, accelerating collagen deposition and promoting angiogenesis. This multifunctional carbon quantum dot platform shows good clinical application prospects in treating bacterial infected wounds. Additionally, the fluorescence characteristics of such carbon dots can be expected to realize visual therapy in the future.

Construction of a one-stop N-doped negatively charged carbon dot nanoplatform with antibacterial and anti-inflammatory dual activities for wound infection based on biocompatibility

The development of bacterial resistance significantly contributes to the persistence of infections. Although previous studies have highlighted the benefits of metal-doped positive carbon nanodots in managing bacterial wound infections, their mechanism of action is relatively simple and they may pose potential hazards to human cells. Therefore, it is essential to develop a one-stop carbon dot nanoplatform that offers high biocompatibility, antibacterial properties, and anti-inflammatory activities for wound infection management. This study explores the antibacterial efficacy, without detectable resistance, and wound-healing potential of nitrogen-doped (N-doped) negatively charged carbon dots (TPP-CDs). These carbon dots are synthesized using tannic acid (TA), polyethylene polyamine, and polyethylene glycol (PEG) as precursors, with a focus on their biocompatibility. Numerous systematic studies have shown that TPP-CDs can effectively destroy bacterial biofilms and deoxyribonucleic acid (DNA), while also inducing oxidative stress, leading to a potent antimicrobial effect. TPP-CDs also demonstrate the ability to scavenge excess free radicals, promote cellular proliferation, and inhibit inflammatory factors, all of which contribute to improved wound healing. TPP-CDs also demonstrate favorable cell imaging capabilities. These findings suggest that N-doped negatively charged TPP-CDs hold significant potential for treating bacterial infections and offer practical insights for their application in the medical field.

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

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

Hydrogels with Antioxidant Microparticles Systems Based on Hyaluronic Acid for Regenerative Wound Healing

This research focuses on the synthesis of hydrogels exhibiting enhanced antioxidant properties derived from hyaluronic acid (HA) and poly(ethylene brassylate-co-squaric acid) (PEBSA), a copolymacrolactone that have the ability to be used in drug delivery applications. Quercetin (Q), a bioflavonoid with strong antioxidant properties, is employed as a bioactive compound. The biomolecule is encapsulated in the polymeric network using different entrapment techniques, including the initial formation of a complex between PEBSA and Q, which is demonstrated through the dynamic light scattering technique. Fourier transform infrared spectroscopy (FT-IR) and rheological studies confirm the formation of the hydrogels, revealing the occurrence of physical interactions between the synthetic polymer and the polysaccharide. Moreover, the hydrogels demonstrate biocompatible properties after direct contact with the HDFa cell line and antioxidant properties, as revealed by DPPH tests.

A bi-functional nanofibrous composite membrane for wound healing applications

Various wound dressings have been developed so far for wound healing, but most of them are ineffective in properly reestablishing the skin's structure, which increases infection risks and dehydration. Electrospun membranes are particularly interesting for wound dressing applications because they mimic the extracellular matrix of healthy skin. In this study, a potential wound healing platform capable of inducing synergistic antibacterial and antioxidation activities was developed by incorporating bio-active rosmarinic acid-hydroxyapatite hybrid (HAP-RA) with different contents (0.5, 1, and 1.5 wt.%) into the electrospun polyamide 6 (PA6) nanofibers. Then, polyethylene glycol (PEG) was introduced to the nanofibrous composite to improve the biocompatibility and biodegradability of the dressing. The results indicated that the hydrophilicity, water uptake, biodegradability, and mechanical properties of the obtained PA6/PEG/HAP-RA nanofibrous composite enhanced at 1 wt.% of HAP-RA. The nanofibrous composite had excellent antibacterial activity. The antioxidation potential of the samples was assessed in vitro. The MTT assay performed on the L929 cell line confirmed the positive effects of the nanofibrous scaffold on cell viability and proliferation. According to the results, the PA6/PEG/HAP-RA nanofibrous composite showed the desirable physiochemical and biological properties besides antibacterial and antioxidative capabilities, making it a promising candidate for further studies in wound healing applications.

Copper Ion-Inspired Dual Controllable Drug Release Hydrogels for Wound Management: Driven by Hydrogen Bonds

Bacterial infections and inflammation progression yield huge trouble for the management of serious skin wounds and burns. However, some hydrogel dressing exhibit poor wound-healing capabilities. Additionally, little information is given on the molecular theory of hydrogel gelation mechanisms and drug release performance from drug-polymer network in the water environment. Herein, cationic guar gum (CG) is first mixed with dipotassium glycyrrhizinate (DG), and then crosslinked Cu2+ to strengthen the mechanical strength followed by encapsulating mussel adhesive protein (MAP) as composite dressings. Intriguingly, CG-Cu2+ 0.5-DG10 possessed proper rheological properties and mechanical strength predominantly driven by strong CG-H2O-Cu2+ and Cu2+-CG hydrogen bonding interaction. Weak DG-CG hydrogen bonding only controlled DG release in the initial 4 h, while strong hydrogen bonding is the main force regulating the sustained release of Cu2+ within 48 h. The incorporation of MAP further loosened the tight crosslinking of CG-Cu2+ 0.5-DG10. The screened CG-Cu2+ 0.5-DG10/MAP possessed excellent self-healing, injectability, antibacterial, anti-inflammatory, cell proliferation-promotion activities with high biocompatibility. Therefore, CG-Cu2+ 0.5-DG10/MAP hydrogel expedited wound closure on S. aureus-infected full-thickness skin wound model and lowered necrosis progression to the unburned interspaces on a rat burn model. The results highlight the promising translational potential of Cu2+-inspired hydrogels for the management of burns and infected wounds.

Engineering injectable hyaluronic acid-based adhesive hydrogels with anchored PRP to pattern the micro-environment to accelerate diabetic wound healing

Diabetic wounds remain a global challenge due to disordered wound healing led by inflammation, infection, oxidative stress, and delayed proliferation. Therefore, an ideal wound dressing for diabetic wounds not only needs tissue adhesiveness, injectability, and self-healing properties but also needs a full regulation of the microenvironment. In this work, adhesive wound dressings (HA-DA/PRP) with injectability were fabricated by combining platelet rich plasma (PRP) and dopamine-modified-hyaluronic acid (HA-DA). The engineered wound dressings exhibited tissue adhesiveness, rapid self-healing, and shape adaptability, thereby enhancing stability and adaptability to irregular wounds. The in vitro experiments demonstrated that HA-DA/PRP adhesives significantly promoted fibroblast proliferation and migration, attributed to the loaded PRP. The adhesives showed antibacterial properties against both gram-positive and negative bacteria. Moreover, in vitro experiments confirmed that HA-DA/PRP adhesives effectively mitigated oxidative stress and inflammation. Finally, HA-DA/PRP accelerated the healing of diabetic wounds by inhibiting bacterial growth, promoting granulation tissue regeneration, accelerating neovascularization, facilitating collagen deposition, and modulating inflammation through inducing M1 to M2 polarization, in an in vivo model of infected diabetic wounds. Overall, HA-DA/PRP adhesives with the ability to comprehensively regulate the microenvironment in diabetic wounds may provide a novel approach to expedite the diabetic wounds healing in clinic.

Optimizing alginate dressings with allantoin and chemical modifiers to promote wound healing

Wound healing requires diverse functionalities in dressings, and conventional materials often fall short in water absorption and moisture regulation. Natural sodium alginate is popular in wound dressings due to its excellent film-forming ability, biocompatibility, ionic crosslinking, and pH responsiveness. However, it has limitations in physical stability and solubility in aqueous environments. This study enhanced alginate dressings by incorporating allantoin and treating with calcium chloride and citric acid to improve physicochemical properties and mechanical performance. Treatments for S2 to S5 prevented dissociation and maintained integrity, with suitable water absorption (363 %-442 %) and water vapor transmission rates (612.53-715.39 g × m2 × day-1). The treatments also improved tensile strength (44.90-55.19 MPa). S2 had the highest migration ratio (52.71 %) of L929 cells and wound healing rates for mice skin (86.6 %), indicating that calcium chloride treatment is beneficial. All dressings (S1 to S5) exhibited low cytotoxicity against L929 cells and low hemolysis ratios, indicating good biocompatibility. Higher allantoin content improved wound healing efficacy. This study provides valuable insights for the design and development of alginate dressings in wound repair, expanding allantoin's application in wound healing.

Synergistic Antimicrobial Glycyrrhizic Acid-Based Functional Biosensing Composite for Sensitive Glucose Monitoring and Collaborative Wound Healing

High glucose blood and bacterial infection remain major issues for the slow healing of diabetic wounds, so developing functional biosensing composite with excellent antibacterial and remarkable glucose response sensitivity is necessary and prospective. Herein, by in situ synthesis AgNPs on the surface of self-prepared PTIGA elastomers, PTIGA-AgNPs conductive composites are obtained with efficient synergistic antibacterial effect, excellent mechanical and self-healing properties. The strain of the composites can reach 1800%, and its self-healing efficiency exceeds 90% at 60 °C within 8 h. Both elastomers and composites represent excellent biocompatibility and the antibacterial rate against E. coli and S. aureus exceeded 90%. Moreover, the biosensor assembled from the conductive composites exhibits excellent glucose response sensitivity and stability, with a sensitivity coefficient of 0.518 mA mm-1 in the range of 0.2-3.6 × 10-3 m glucose concentration, as well as a low detection limit of 0.08 × 10-3 m. Furthermore, based on the remarkable antibacterial performance and bioactivity derived from GA, the composites reduce the expression of pro-inflammatory factors and promote the production of anti-inflammatory factors, and effectively promote the regeneration of skin and granulation tissue of wounds in a diabetic full-thickness skin defect model, demonstrating the enormous therapeutic potential in diabetic wound healing.

Hepatocyte Growth Factor DNA Aptamer for Prevention of Postoperative Peritoneal Adhesion via Enhancement of Fibrinolysis and Inhibition of Mesothelial Mesenchymal Transition

Postoperative peritoneal adhesion (PPA) is a prevalent complication of abdominal surgery, posing a significant hindrance to postsurgical recovery. Although several strategies have been developed to alleviate and prevent adhesions, their efficacy remains unsatisfactory. For the first time, we studied the therapeutic effect and mechanism of our recently developed thermally stable oligonucleotide-based mimetics of hepatocyte growth factor (HGF DNA aptamer) to prevent PPA. The HGF DNA aptamer effectively inhibited canonical TGF-β1 signaling transduction, partially suppressing mesothelial mesenchymal transition. Additionally, the aptamer, respectively, upregulated and downregulated the expression of tissue plasminogen activator and plasminogen activator inhibitor 1, thereby enhancing fibrinolytic activity. As a pleiotropic factor, the HGF DNA aptamer also enhanced the migratory and proliferative capacities of mesothelial cells. Finally, the aptamer demonstrated a higher level of effectiveness in preventing PPAs than the commercially available antiperitoneal adhesion barrier, Seprafilm. Due to its therapeutic benefits, excellent stability, biosafety, cost-effectiveness, and versatility, the HGF DNA aptamer demonstrates promise for preventing PPA in future clinical settings.

A Double Network Composite Hydrogel with Self-Regulating Cu2+/Luteolin Release and Mechanical Modulation for Enhanced Wound Healing

Designing adaptive and smart hydrogel wound dressings to meet specific needs across different stages of wound healing is crucial. Here, we present a composite hydrogel, GSC/PBE@Lut, that offers self-regulating release of cupric ions and luteolin and modulates mechanical properties to promote chronic wound healing. The double network hydrogel, GSC, is fabricated through photo-cross-linking of gelatin methacrylate, followed by Cu2+-alginate coordination cross-linking. On one hand, GSC allows for rapid Cu2+ release to eliminate bacteria in the acidic pH environment during inflammation and reduces the hydrogel's mechanical strength to minimize tissue trauma during early dressing changes. On the other hand, GSC enables slow Cu2+ release during the proliferation stage, promoting angiogenesis and biocompatibility. Furthermore, the inclusion of pH- and reactive oxygen species (ROS)-responsive luteolin nanoparticles (PBE@Lut) in the hydrogel matrix allows for controlled release of luteolin, offering antioxidant and anti-inflammatory effects and promoting anti-inflammatory macrophage polarization. In a murine model of Staphylococcus aureus infected wounds, GSC/PBE@Lut demonstrates exceptional therapeutic benefits in antibacterial, anti-inflammatory, angiogenic, and tissue regeneration. Overall, our results suggest that smart hydrogels with controlled bioactive agent release and mechanical modulation present a promising solution for treating chronic wounds.

Nature-Inspired Gelatin-Based Adhesive Hydrogel: A Rapid and User-Friendly Solution for Hemostatic Applications

Conventional hemostatic agents face challenges in achieving rapid hemostasis and effective tissue repair due to limited hemostatic scenarios, suboptimal efficacy, and inadequate adhesion to wet tissues. Drawing inspiration from nature-sourced materials, a gelatin-based adhesive hydrogel (AOT)  is designed, easily prepared and quick to form, driven by Schiff base and multiple hydrogen bonds for applications in arterial and liver bleeding models. AOT exhibits exceptional adhesion to wet tissues (48.67 ± 0.16 kPa) and displays superior hemostatic properties with reduced blood loss and hemostatic time compared to other hydrogels and conventional hemostatic materials. Moreover, AOT exhibits good biocompatibility and biodegradability. In summary, this easily prepared adhesive hydrogel has the potential to supplant traditional hemostatic agents, offering a novel approach to achieve swift sealing of hemostasis and facilitate wound healing and repair in broader application scenarios, owing to its unique advantages.

Genipin crosslinked quaternary ammonium chitosan hydrogels for wound dressings

Bacterial infection can lead to various complications, such as inflammations on surrounding tissues, which can prolong wound healing and thus represent a significant clinical and public healthcare problem. Herein, a report on the fabrication of a novel genipin/quaternized chitosan (CS) hydrogel for wound dressing is presented. The hydrogel was prepared by mixing quaternized CS and genipin under 35 °C bath. The hydrogels showed porous structure (250-500 μm) and mechanical properties (3000-6000 Pa). In addition, the hydrogels displayed self-healing ability and adhesion performance on different substrates. Genipin crosslinked quaternized CS hydrogels showed antibacterial activities againstE. coliandS. aureus. The CCK-8 and fluorescent images confirmed the cytocompatibility of hydrogels by seeding with NIH-3T3 cells. The present study showed that the prepared hydrogel has the potential to be used as wound dressing.

Unveiling the versatility of gelatin methacryloyl hydrogels: a comprehensive journey into biomedical applications

Gelatin methacryloyl (GelMA) hydrogels have gained significant recognition as versatile biomaterials in the biomedical domain. GelMA hydrogels emulate vital characteristics of the innate extracellular matrix by integrating cell-adhering and matrix metalloproteinase-responsive peptide motifs. These features enable cellular proliferation and spreading within GelMA-based hydrogel scaffolds. Moreover, GelMA displays flexibility in processing, as it experiences crosslinking when exposed to light irradiation, supporting the development of hydrogels with adjustable mechanical characteristics. The drug delivery landscape has been reshaped by GelMA hydrogels, offering a favorable platform for the controlled and sustained release of therapeutic actives. The tunable physicochemical characteristics of GelMA enable precise modulation of the kinetics of drug release, ensuring optimal therapeutic effectiveness. In tissue engineering, GelMA hydrogels perform an essential role in the design of the scaffold, providing a biomimetic environment conducive to cell adhesion, proliferation, and differentiation. Incorporating GelMA in three-dimensional printing further improves its applicability in drug delivery and developing complicated tissue constructs with spatial precision. Wound healing applications showcase GelMA hydrogels as bioactive dressings, fostering a conducive microenvironment for tissue regeneration. The inherent biocompatibility and tunable mechanical characteristics of GelMA provide its efficiency in the closure of wounds and tissue repair. GelMA hydrogels stand at the forefront of biomedical innovation, offering a versatile platform for addressing diverse challenges in drug delivery, tissue engineering, and wound healing. This review provides a comprehensive overview, fostering an in-depth understanding of GelMA hydrogel's potential impact on progressing biomedical sciences.

Injectable hydrogel harnessing foreskin mesenchymal stem cell-derived extracellular vesicles for treatment of chronic diabetic skin wounds

Chronic skin wounds are a serious complication of diabetes with a high incidence rate, which can lead to disability or even death. Previous studies have shown that mesenchymal stem cells derived extracellular vesicles (EVs) have beneficial effects on wound healing. However, the human foreskin mesenchymal stem cell (FSMSCs)-derived extracellular vesicle (FM-EV) has not yet been isolated and characterized. Furthermore, the limited supply and short lifespan of EVs also hinder their practical use. In this study, we developed an injectable dual-physical cross-linking hydrogel (PSiW) with self-healing, adhesive, and antibacterial properties, using polyvinylpyrrolidone and silicotungstic acid to load FM-EV. The EVs were evenly distributed in the hydrogel and continuously released. In vivo and vitro tests demonstrated that the synergistic effect of EVs and hydrogel could significantly promote the repair of diabetic wounds by regulating macrophage polarization, promoting angiogenesis, and improving the microenvironment. Overall, the obtained EVs-loaded hydrogels developed in this work exhibited promising applicability for the repair of chronic skin wounds in diabetes patients.

Ferrocene-Based Antioxidant Self-Healing Hydrogel via the Biginelli Reaction for Wound Healing

The development of antioxidant wound dressings to remove excessive free radicals around wounds is essential for wound healing. In this study, we developed an efficient strategy to prepare antioxidant self-healing hydrogels as wound dressings by combining multicomponent reactions (MCRs) and postpolymerization modification. A polymer containing ferrocene and phenylboronic acid groups was developed via the Biginelli reaction, followed by efficient modification. This polymer is antioxidant due to its ferrocene moieties and can rapidly cross-link poly(vinyl alcohol) to realize an antioxidant self-healing hydrogel through dynamic borate ester linkages. This hydrogel has low cytotoxicity and is biocompatible. In in vivo experiments, this hydrogel is superior to existing clinical dressings in promoting wound healing. This study demonstrates the value of the Biginelli reaction in exploring biomaterials, potentially offering insights into the design of other multifunctional polymers and related materials using different MCRs.

An Injectable, Self-Healing, Adhesive Multifunctional Hydrogel Promotes Bacteria-Infected Wound Healing

Bacterial infections have a serious impact on public health. It is urgent to develop antibacterial hydrogels with good biocompatibility to reduce the use of antibiotics. In this study, poly(lipoic acid-co-sodium lipoate)-phytic acid (P(LA-SL)-PA) hydrogels are prepared by a simple mixture of the natural small molecules lipoic acid (LA) and phytic acid (PA) in a mild and green reaction environment. The crosslinking network is constructed through the connection of covalent disulfide bonds as well as the hydrogen bonds, which endow the injectable and self-healing properties. The P(LA-SL)-PA hydrogels exhibit an adjustable compression modulus and adhesion. The in vitro agar plates assay indicates that the antibacterial rate of hydrogels against Escherichia coli and Staphylococcus aureus is close to 95%. In the rat-infected wound model, the P(LA-SL)-PA hydrogels adhere closely to the tissue and promote epithelialization and collagen deposition with a significant effect on wound healing. These results prove that the P(LA-SL)-PA hydrogels could act as effective wound dressings for promoting the healing of infected wounds.

Glucose-Responsive Self-Healing Bilayer Drug Microneedles Promote Diabetic Wound Healing Via a Trojan-Horse Strategy

Chronic nonhealing wounds are serious complications of diabetes with a high morbidity, and they can lead to disability or death. Conventional drug therapy is ineffective for diabetic wound healing because of the complex environment of diabetic wounds and the depth of drug penetration. Here, we developed a self-healing, dual-layer, drug-carrying microneedle (SDDMN) for diabetic wound healing. This SDDMN can realize transdermal drug delivery and broad-spectrum sterilization without drug resistance and meets the multiple needs of the diabetic wound healing process. Quaternary ammonium chitosan cografted with dihydrocaffeic acid (Da) and l-arginine and oxidized hyaluronic acid-dopamine are the main parts of the self-healing hydrogel patch. Methacrylated poly(vinyl alcohol) (methacrylated PVA) and phenylboronic acid (PBA) were used as the main part of the MN, and gallium porphyrin modified with 3-amino-1,2 propanediol (POGa) and insulin were encapsulated at its tip. Under hyperglycaemic conditions, the PBA moiety in the MN reversibly formed a glucose-boronic acid complex that promoted the rapid release of POGa and insulin. POGa is disguised as hemoglobin through a Trojan-horse strategy, which is then taken up by bacteria, allowing it to target bacteria and infected lesions. Based on the synergistic properties of these components, SDDMN-POGa patches exhibited an excellent biocompatibility, slow drug release, and antimicrobial properties. Thus, these patches provide a potential therapeutic approach for the treatment of diabetic wounds.

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.

Nitric oxide-releasing multifunctional catechol-modified chitosan/oxidized dextran hydrogel with antibacterial, antioxidant, and pro-angiogenic properties for MRSA-infected diabetic wound healing

The study presents a multifunctional catechol-modified chitosan (Chi-Ca)/oxidized dextran (Dex-CHO) hydrogel (CDP-PB) that possesses antibacterial, antioxidant, and pro-angiogenic properties, aimed at improving the healing of diabetic wounds. The achievement of the as-prepared CDP-PB hydrogel with superb antibacterial property (99.9 %) can be realized through the synergistic effect of phenylboronic acid-modified polyethyleneimine (PEI-PBA) and photothermal therapy (PTT) of polydopamine nanoparticles loaded with the nitric oxide (NO) donor BNN6 (PDA@BNN6). Notably, CDP-PB hydrogel achieves ∼3.6 log10 CFU/mL MRSA of inactivation efficiency under 808 nm NIR laser irradiation. In order to mitigate oxidative stress, the Chi-Ca was synthesized and afterward subjected to a reaction with Dex-CHO via a Schiff-base reaction. The catechol-containing hydrogel demonstrated its effectiveness in scavenging DPPH, •OH, and ABTS radicals (> 85 %). In addition, the cellular experiment illustrates the increased migration and proliferation of cells by the treatment of CDP-PB hydrogel in the presence of oxidative stress conditions. Moreover, the findings from the animal model experiments provide evidence that the CDP-PB hydrogel exhibited efficacy in the eradication of wound infection, facilitation of angiogenesis, stimulation of granulation, and augmentation of collagen deposition. These results indicate the potential of the CDP-PB hydrogel for use in clinical applications.

Regenerated silk fibroin coating stable liquid metal nanoparticles enhance photothermal antimicrobial activity of hydrogel for wound infection repair

The integration of liquid metal (LM) and regenerated silk fibroin (RSF) hydrogel holds great potential for achieving effective antibacterial wound treatment through the LM photothermal effect. However, the challenge of LM's uncontrollable shape-deformability hinders its stable application. To address this, we propose a straightforward and environmentally-friendly ice-bath ultrasonic treatment method to fabricate stable RSF-coated eutectic gallium indium (EGaIn) nanoparticles (RSF@EGaIn NPs). Additionally, a double-crosslinked hydrogel (RSF-P-EGaIn) is prepared by incorporating poly N-isopropyl acrylamide (PNIPAAm) and RSF@EGaIn NPs, leading to improved mechanical properties and temperature sensitivity. Our findings reveal that RSF@EGaIn NPs exhibit excellent stability, and the use of near-infrared (NIR) irradiation enhances the antibacterial behavior of RSF-P-EGaIn hydrogel in vivo. In fact, in vivo testing demonstrates that wounds treated with RSF-P-EGaIn hydrogel under NIR irradiation completely healed within 14 days post-trauma infection, with the formation of new skin and hair. Histological examination further indicates that RSF-P-EGaIn hydrogel promoted epithelialization and well-organized collagen deposition in the dermis. These promising results lay a solid foundation for the future development of drug release systems based on photothermal-responsive hydrogels utilizing RSF-P-EGaIn.

Advanced multifunctional hydrogels for diabetic foot ulcer healing: Active substances and biological functions

AIM

Hydrogels with excellent biocompatibility and biodegradability can be used as the desirable dressings for the therapy of diabetic foot ulcer (DFU). This review aimed to summarize the biological functions of hydrogels, combining with the pathogenesis of DFU.

METHODS

The studies in the last 10 years were searched and summarized from the online database PubMed using a combination of keywords such as hydrogel and diabetes. The biological functions of hydrogels and their healing mechanism on DFU were elaborated.

RESULTS

In this review, hydrogels were classified by their active substances such as drugs, cytokines, photosensitizers, and biomimetic peptide. Based on this, the biological functions of hydrogels were summarized by associating the pathogenesis of DFU, including oxidative stress, chronic inflammation, cell phenotype change, vasculopathy, and infection. This review also pointed out some of the shortcomings of hydrogels in present researches.

CONCLUSIONS

Hydrogels were classified into carrier hydrogels and self-functioning hydrogels in this review. Besides, the functions and components of existing hydrogels were clarified to provide assistance for future researches and clinical applications.

Injectable Bioadhesive Photocrosslinkable Hydrogels with Sustained Release of Kartogenin to Promote Chondrogenic Differentiation and Partial-Thickness Cartilage Defects Repair

Partial-thickness cartilage defect (PTCD) is a common and formidable clinical challenge without effective therapeutic approaches. The inherent anti-adhesive characteristics of the extracellular matrix within cartilage pose a significant impediment to the integration of cells or biomaterials with the native cartilage during cartilage repair. Here, an injectable photocrosslinked bioadhesive hydrogel, consisting of gelatin methacryloyl (GM), acryloyl-6-aminocaproic acid-g-N-hydroxysuccinimide (AN), and poly(lactic-co-glycolic acid) microspheres loaded with kartogenin (KGN) (abbreviated as GM/AN/KGN hydrogel), is designed to enhance interfacial integration and repair of PTCD. After injected in situ at the irregular defect, a stable and robust hydrogel network is rapidly formed by ultraviolet irradiation, and it can be quickly and tightly adhered to native cartilage through amide bonds. The hydrogel exhibits good adhesion strength up to 27.25 ± 1.22 kPa by lap shear strength experiments. The GM/AN/KGN hydrogel demonstrates good adhesion, low swelling, resistance to fatigue, biocompatibility, and chondrogenesis properties in vitro. A rat model with PTCD exhibits restoration of a smoother surface, stable seamless integration, and abundant aggrecan and type II collagen production. The injectable stable adhesive hydrogel with long-term chondrogenic differentiation capacity shows great potential to facilitate repair of PTCD.

Slightly photo-crosslinked chitosan/silk fibroin hydrogel adhesives with hemostasis and anti-inflammation for pro-healing cyclophosphamide-induced hemorrhagic cystitis

Cyclophosphamide is commonly used in the treatment of various cancers and autoimmune diseases, while concurrently imposing substantial toxicity on the bladder, frequently manifesting hemorrhagic cystitis. Intravesical interventions, such as hyaluronic acid supplementation, present a therapeutic strategy to reinstate bladder barrier function and alleviate the effects of metabolic toxicants. However, it remains a great challenge to achieve efficient cyclophosphamide-induced hemorrhagic cystitis (CHC) management with accelerated tissue repair owing to the low wet-adhesion, poor hemostasis, and acute inflammatory responses. To address these issues, a hemostatic and anti-inflammatory hydrogel adhesive of chitosan methylacryloyl/silk fibroin methylacryloyl (CHMA/SFMA) is developed for promoting the healing of CHC. The obtained hydrogels show a high adhesive strength of 26.21 N/m with porcine bladder, facilitating the rapid hemostasis within 15 s, and reinstate bladder barrier function. Moreover, this hydrogel adhesive promotes the proliferation and aggregation of SV-HUC-1 and regulates macrophage polarization. Implanting the hydrogels into CHC bladders of a SD rat model, they not only can be completely biodegraded in 14 days, but also effectively control hematuria and inflammation, and accelerate angiogenesis, thereby significantly promote the healing of bladder injury. Overall, CHMA/SFMA hydrogels exhibit rapid hemostasis for treating CHC and accelerate muscle tissue repair via angiogenesis and inflammation amelioration, which may provide a new path for managing severe hemorrhagic cystitis in the clinics.

A Poloxamer 407/chitosan-based thermosensitive hydrogel dressing for diabetic wound healing via oxygen production and dihydromyricetin release

The current clinical treatment of diabetic wounds is still based on oxygen therapy, and the slow healing of skin wounds due to hypoxia has always been a key problem in the repair of chronic skin injuries. To overcome this problem, the oxygen-producing matrix CaO2NPS based on the temperature-sensitive dihydromyricetin-loaded hydrogel was prepared. In vitro activity showed that the dihydromyricetin (DHM) oxygen-releasing temperature-sensitive hydrogel composite (DHM-OTH) not only provided a suitable oxygen environment for cells around the wound to survive but also had good biocompatibility and various biological activities. By constructing a T2D wound model, we further investigated the repairing effect of DHM-OTH on chronic diabetic skin wounds and the mechanisms involved. DHM-OTH was able to reduce inflammatory cells and collagen deposition and promote angiogenesis and cell proliferation for diabetic wound healing. These in vitro and in vivo data suggest that DHM-OTH accelerates diabetic wound repair as a novel method to efficiently deliver oxygen to wound tissue, providing a promising strategy to improve diabetic wound healing.

A novel bola-molecular self-assembling hydrogel for enhancing diabetic wound healing

HYPOTHESIS

Chronic wounds, particularly those caused by diabetes, pose a significant challenge for clinical treatment due to their prolonged healing process and associated complications, which can lead to increased morbidity. A biocompatible hydrogel with strong antibacterial properties and the ability to promote angiogenesis can be directly absorbed in the wound site for healing.

EXPERIMENTS

A series of self-healing, antibacterial bolaamphiphilic supramolecular self-assembling hydrogels (HLQMes/Cu) were developed based on metal-ligand coordination between various concentrations of Cu2+ solution and the head group of l-histidine methyl ester in HLQMes. This is the first report on the application of bola-molecular supramolecular hydrogels for the treatment of chronic wounds.

FINDINGS

The bola-molecular hydrogels reduced the toxicity of copper ions by coordination, and the HLQMes/Cu hydrogel, with 1.3 mg/mL Cu2+ (HLQMes/Cu1.3), demonstrated good biocompatibility and antibacterial properties and effectively enhanced wound healing in a diabetic wound model with full-thickness injuries. Immunohistochemical analysis revealed that the HLQMes/Cu1.3 hydrogel enhanced epithelial formation and collagen deposition in wounds. Immunofluorescence studies confirmed that the HLQMes/Cu1.3 hydrogel attenuated the expression of proinflammatory factor (IL-6) and promoted angiogenesis by upregulating α-SMA and CD31. These findings demonstrate the potential of this bolaamphiphilic supramolecular self-assembling hydrogel as a promising candidate for diabetic wound treatment.

Tailored gelatin methacryloyl-based hydrogel with near-infrared responsive delivery of Qiai essential oils boosting reactive oxygen species scavenging, antimicrobial, and anti-inflammatory activities for diabetic wound healing

The management of diabetic wounds poses a substantial economic and medical burden for diabetic patients. Oxidative stress and persistent bacterial infections are considered to be the primary factors. Qiai essential oil (QEO) exhibits various pharmacological characteristics, including inflammatory-reducing, antibacterial, and antioxidant properties. Nevertheless, the hydrophobic nature and propensity for explosive release of this substance present constraints on its potential for future applications. Here, we developed a stimulus-responsive hydrogel to overcome the multiple limitations of QEO-based wound dressings. The QEO was encapsulated within graphene oxide (GO) through repeated extrusion using an extruder. Subsequently, QEO@GO nanoparticles were incorporated into a Gelatin-methacryloyl (GelMA) hydrogel. The QEO@GO-GelMA hydrogel demonstrated controlled release ablation, photothermal antibacterial effects, and contact ablation against two representative bacterial strains. It effectively reduced reactive oxygen species (ROS) generation, promoted angiogenesis, and decreased levels of the pro-inflammatory cytokine interleukin-6 (IL-6), thereby accelerating the healing process of diabetic wounds. In addition, in vitro and in vivo tests provided further evidence of the favorable biocompatibility of this multifunctional hydrogel dressing. Overall, the QEO@GO-GelMA hydrogel provides numerous benefits, encompassing antimicrobial properties, ROS-scavenging abilities, anti-inflammatory effects, and the capacity to expedite diabetic wound healing. These attributes make it an optimal choice for diabetic wound management.

Influence of chitosan and hydroxyethyl cellulose modifications towards the design of cross-linked double networks hydrogel for diabetic wound healing

The wound dressings' lack of antioxidant and antibacterial properties, and delayed wound healing limit their use in wound treatment and management. Recent advances in dressing materials are aimed at improving the limitations discussed above. Therefore, the aim of this study includes the preparation and characterization of oxidized hydroxyethyl cellulose (OHEC) and ferulic acid-grafted chitosan (CS-FA) hydrogel loaded with green synthesized selenium nanoparticles (Se NPs) (OHEC-CS-FA-Se NPs named as nanohydrogel) for diabetic wound healing. The structure and properties of the hydrogel was characterized by FTIR, FE-SEM, HR-TEM, EDAX, UV-Vis spectrophotometry, XRD, DLS, zeta potential and rheological studies. The findings of these experiments demonstrate that nanohydrogel possesses a variety of outstanding qualities, including an optimal gel time, good swelling characteristics, a fair water retention rate, a good degradation rate, and strong mechanical stability. Nanohydrogel has been shown to have a synergistic impact by significantly increasing antioxidant activity by scavenging ABTS and DPPH radicals. The nanohydrogel's strong biocompatibility was confirmed by cytocompatibility testing using L929 mouse fibroblast cells. In addition, the wound healing potential of nanohydrogel was tested on L929 cells by an in vitro scratch assay and the nanohydrogel showed a wound closure rate of 100 % after 12 h. In addition to this study, nanohydrogel has demonstrated significant antimicrobial properties against human and wound infection causing pathogens such as Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa. In the animal model, almost complete diabetic wound healing was achieved on day 14 after application of the nanohydrogel. The results obtained indicate that the multifunctional bioactive nature of OHEC-CS-FA-Se NPs showed exceptional antioxidant and antibacterial potential for the treatment of infected and chronic wounds.

Hyaluronic acid-decorated curcumin-based coordination nanomedicine for enhancing the infected diabetic wound healing

Persistent over-oxidation, inflammation and bacterial infection are the primary reasons for impaired wound repairing in diabetic patients. Therefore, crucial strategies to promote diabetic wound repairing involve suppressing the inflammatory response, inhibiting bacterial growth and decreasing reactive oxygen species (ROS) within the wound. In this work, we develop a multifunctional nanomedicine (HA@Cur/Cu) designed to facilitate the repairing process of diabetic wound. The findings demonstrated that the synthesized infinite coordination polymers (ICPs) was effective in enhancing the bioavailability of curcumin and improving the controlled drug release at the site of inflammation. Furthermore, in vitro and in vivo evaluation validate the capacity of HA@Cur/Cu to inhibit bacterial growth and remove excess ROS and inflammatory mediators, thereby significantly promoting the healing of diabetic wound in mice. These compelling findings strongly demonstrate the enormous promise of this multifunctional nanomedicine for the treatment of diabetic wound.

Advancements in Regenerative Hydrogels in Skin Wound Treatment: A Comprehensive Review

This state-of-the-art review explores the emerging field of regenerative hydrogels and their profound impact on the treatment of skin wounds. Regenerative hydrogels, composed mainly of water-absorbing polymers, have garnered attention in wound healing, particularly for skin wounds. Their unique properties make them well suited for tissue regeneration. Notable benefits include excellent water retention, creating a crucially moist wound environment for optimal healing, and facilitating cell migration, and proliferation. Biocompatibility is a key feature, minimizing adverse reactions and promoting the natural healing process. Acting as a supportive scaffold for cell growth, hydrogels mimic the extracellular matrix, aiding the attachment and proliferation of cells like fibroblasts and keratinocytes. Engineered for controlled drug release, hydrogels enhance wound healing by promoting angiogenesis, reducing inflammation, and preventing infection. The demonstrated acceleration of the wound healing process, particularly beneficial for chronic or impaired healing wounds, adds to their appeal. Easy application and conformity to various wound shapes make hydrogels practical, including in irregular or challenging areas. Scar minimization through tissue regeneration is crucial, especially in cosmetic and functional regions. Hydrogels contribute to pain management by creating a protective barrier, reducing friction, and fostering a soothing environment. Some hydrogels, with inherent antimicrobial properties, aid in infection prevention, which is a crucial aspect of successful wound healing. Their flexibility and ability to conform to wound contours ensure optimal tissue contact, enhancing overall treatment effectiveness. In summary, regenerative hydrogels present a promising approach for improving skin wound healing outcomes across diverse clinical scenarios. This review provides a comprehensive analysis of the benefits, mechanisms, and challenges associated with the use of regenerative hydrogels in the treatment of skin wounds. In this review, the authors likely delve into the application of rational design principles to enhance the efficacy and performance of hydrogels in promoting wound healing. Through an exploration of various methodologies and approaches, this paper is poised to highlight how these principles have been instrumental in refining the design of hydrogels, potentially revolutionizing their therapeutic potential in addressing skin wounds. By synthesizing current knowledge and highlighting potential avenues for future research, this review aims to contribute to the advancement of regenerative medicine and ultimately improve clinical outcomes for patients with skin wounds.

F-free etching and ingenious construction of hydrogel layer-prepared MXene membranes for oily wastewater separation

A strategy for the preparation of hydrogel layer MXene membranes by an F-free method was proposed. It maintained high permeance (2686.1 L m-2 h-1 bar-1) and separation efficiency (99.99%) even after 300 min of emulsion separation. The membrane resisted harsh chemical and microbiological environments and efficiently treated actual oily wastewater.

Copper Nanodots-Based Hybrid Hydrogels with Multiple Enzyme Activities for Acute and Infected Wound Repair

Effectively controlling bacterial infection, reducing the inflammation and promoting vascular regeneration are all essential strategies for wound repair. Nanozyme technology has potential applications in the treatment of infections because its non-antibiotic dependent, topical and noninvasive nature. In wound management, copper-based nanozymes have emerged as viable alternatives to antibiotics. In this study, an ultrasmall cupric enzyme with high enzymatic activity is synthesized and added to a nontoxic, self-healing, injectable cationic guar gum (CG) hydrogel network. The nanozyme exhibits remarkable antioxidant properties under neutral conditions, effectively scavenging reactive nitrogen and oxygen species (RNOS). Under acidic conditions, Cu NDs have peroxide (POD) enzyme-like activity, which allows them to eliminate hydrogen peroxides and produce free radicals locally. Antibacterial experiments show that they can kill bacteria and remove biofilms. It reveals that low concentrations of Cu ND/CG decrease the expression of the inflammatory factors in cells and tissues, effectively controlling inflammatory responses. Cu ND/CG hydrogels also inhibit HIF-1α and promote VEGF expression in the wound with the ability to promote vascular regeneration. In vivo safety assessments reveal a favorable biosafety profile. Cu ND/CG hydrogels offer a promising solution for treating acute and infected wounds, highlighting the potential of innovative nanomaterials in wound healing.

Double-layered microneedle patch loaded with bioinspired nano-vaccine for melanoma treatment and wound healing

Malignant melanoma is a challenging problem worldwide, because the remaining tumor cells and extensive skin defects following surgical resection are difficult to treat. Biomaterial-mediated immunotherapy has emerged as a superior strategy for anti-tumor applications in recent years. Herein, a unique double-layer MNP was developed to address the problem of malignant melanoma. Hydroxyapatite (HAP) and short-chain peptides from tumor cells were self-assembled to prepare the bioinspired nano-vaccine, and then they were loaded onto the microneedle tips of methacrylated gelatin (GelMA)-based MNP. The products (dubbed HVMN) demonstrated relatively good biocompatibility and immune activity, inhibiting the proliferation and inducing apoptosis of malignant melanoma in a B16 cell-bearing model of C57BL/6 mice, and promoting skin tissue regeneration in a full thickness skin defect model of SD rats in 15 days. The putative molecular pathways were examined preliminarily. In conclusion, this research will develop a competitive microneedle patch with dual anti-tumor and pro-regenerative properties for the postoperative treatment of malignant melanoma.

Mussel-inspired "all-in-one" sodium alginate/carboxymethyl chitosan hydrogel patch promotes healing of infected wound

Hydrogels have been widely used as wound dressings to accelerate wound healing. However, due to the impaired skin barrier at the wound site, external bacteria can easily invade the wound and cause infection. In this study, we designed a dopamine-modified sodium alginate/carboxymethyl chitosan/polyvinylpyrrolidone (CPD) hydrogel, which was able to promote wound healing while preventing wound infection. Due to the high content of catechol groups, the CPD hydrogel exhibited good tissue adhesion ability and a significant scavenging ability for DPPH• and PTIO• radicals. Under near-infrared laser irradiation, the temperature of CPD hydrogel increased significantly, which significantly killed the Staphylococcus aureus and Escherichia coli. The cell migration test confirmed that CPD hydrogel could promote the cell migration ratio. In the in vivo wound healing test for infected full-thickness skin defect, CPD hydrogel significantly inhibited bacterial proliferation and enhanced wound healing rate. Therefore, the multifunctional hydrogel is expected to be applied to wound healing.

Multifunctional On-Demand Removability Hydrogel Dressing Based on in Situ Formed AgNPs, Silk Microfibers and Hydrazide Hyaluronic Acid for Burn Wound Healing

Elevated temperatures can deactivate tissues in the burn wound area, allowing pathogenic bacteria to multiply on the wound surface, ultimately leading to local or systemic infection. An ideal burn dressing should provide antibacterial properties and facilitate painless dressing changes. Silk microfibers coated with poly (2, 3, 4-trihydroxybenzaldehyde) (referred to as mSF@PTHB) to in situ reduce AgNO3 to silver nanoparticles (AgNPs) in a hydrazide hyaluronic acid-based hydrogel are utilized. The findings indicate a more homogeneous distribution of the silver elements compared to directly doped AgNPs, which also conferred antioxidant and antibacterial properties to the hydrogel. Moreover, hydrogels containing pH-responsive dynamic acylhydrazone bonds can undergo a gel-sol transition in a weak acid environment, leading to the painless removal of adhesive hydrogel dressings. Notably, the on-demand replaceable self-healing antioxidant hydrogel dressing exhibits antibacterial effects and cytocompatibility in vitro, and the wound-healing performance of the hydrogel is validated by treating a burn mouse model with full-thickness skin defects. It is demonstrated that hydrogel dressings offer a viable therapeutic approach to prevent infection and facilitate the healing of burn wounds.

β-Glucans obtained from fungus for wound healing: A review

The cell surface of fungus contains a large number of β-glucans, which exhibit various biological activities such as immunomodulatory, anti-inflammatory, and antioxidation. Fungal β-glucans with highly branched structure show great potential as wound healing reagents, because they can stimulate the expression of many immune- and inflammatory-related factors beneficial to wound healing. Recently, the wound healing ability of many fungal β-glucans have been investigated in animals and clinical trials. Studies have proved that fungal β-glucans can promote fibroblasts proliferation, collagen deposition, angiogenesis, and macrophage infiltration during the wound healing process. However, the development of fungal β-glucans as wound healing reagents is not systematically reviewed till now. This review discusses the wound healing studies of β-glucans obtained from different fungal species. The structure characteristics, extraction methods, and biological functions of fungal β-glucans with wound healing ability are summarized. Researches about fungal β-glucan-containing biomaterials and structurally modified β-glucans for wound healing are also involved.

Copper-doped bismuth oxychloride nanosheets assembled into sphere-like morphology for improved photocatalytic inactivation of drug-resistant bacteria

The devastating microbiological contamination as well as emerging drug-resistant bacteria has posed severe threats to the ecosystem and public health, which propels the continuous exploitation of safe yet efficient disinfection products and technology. Here, copper doping engineered bismuth oxychloride (Cu-BiOCl) nanocomposite with a hierarchical spherical structure was successfully prepared. It was found that due to the exposure of abundant active sites for the adsorption of both bacteria cells and molecular oxygen in the structure, the obtained Cu-BiOCl with nanosheets assembled into sphere-like morphology exhibited remarkable photocatalytic antibacterial effects. In particular, compared to the pure BiOCl, composite Cu-BiOCl possessed improved antibacterial effects against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Methicillin-resistant Staphylococcus aureus (MRSA). The combination of physicochemical characterizations and theoretical calculations has revealed that copper doping significantly promoted the light absorbance, inhibited the recombination of electron-hole pairs, and enhanced molecular oxygen adsorption, which resulted in more generation of active species including reactive oxygen species (ROS) and h+ to achieve superior photocatalytic bacterial inactivation. Finally, transcriptome analysis on MRSA pinpointed photocatalytic inactivation induced by Cu-BiOCl may retard largely the development of drug-resistance. Therefore, the built spherical Cu-BiOCl nanocomposite has provided an ecofriendly, economical and robust strategy for the efficient removal of drug-resistant bacteria with promising potentials for environmental and healthcare utilizations.

Gelatin/Polyacrylamide-Based Antimicrobial and Self-Healing Hydrogel Film for Wound Healing Application

In this study, a self-healing, adhesive, and superabsorbent film made of gelatin, poly(acrylamide), and boric acid (GelAA) was successfully synthesized using a free radical reaction mechanism. The optimized film showed a remarkable 2865 ± 42% water absorptivity and also exhibited excellent self-healing behavior. The GelAA films were further loaded with silver nanoclusters (AgNCs) and ursodeoxycholic acid (UDC) (loading efficiency = 10%) to develop UDC/Ag/GelAA films. The loading of AgNCs in UDC/Ag/GelAA films helped in exhibiting 99.99 ± 0.01% antibacterial activity against both Gram-positive and Gram-negative bacteria, making them very effective against bacterial infections. Additionally, UDC/Ag/GelAA films had 77.19 ± 0.52% porosity and showed 90% of UDC release in 30 h, which helps in improving the cell proliferation. Our research provides an easy but highly effective process for synthesizing a hydrogel film, which is an intriguing choice for wound healing applications without the use of antibiotics.

A guanosine/konjac glucomannan supramolecular hydrogel with antioxidant, antibacterial and immunoregulatory properties for cutaneous wound treatment

Developing naturally-derived wound dressing materials with intrinsic therapeutic effects is desirable for the clinical applications. Recently, guanosine-based supramolecular G-quadruplex (G4) hydrogel exhibited great potential in preparing biological materials due to its simple fabrication method and responsive gel networks. However, the weak mechanical properties and the consequent burst release of bioactive molecules restrict its clinical applications. Herein, we found that konjac glucomannan (KGM) with immunoregulatory effect did not affect the self-assembly of G-quadruplexes and thus effectively enhancing the mechanical properties of G4 hydrogel. Aloin, as a model drug, was in situ loaded into gel networks, finally obtaining the G4/Aloin-KGM hydrogel. This hydrogel exhibited porous morphology, swelling ability and hemostatic capability. Boronate bonds in G4 networks and aloin collectively endowed the hydrogel with excellent antioxidant performance. Meanwhile, aloin also provided outstanding in vitro and in vivo bactericidal ability. The wounds treated with this biocompatible hydrogel demonstrated faster regeneration of epithelial and dermal tissues, and the whole wound healing stages were accelerated by promoting collagen deposition, facilitating macrophage polarization towards M2 phenotype, down-regulating the expression level of IL-6, and up-regulating the expression level of IL-10, CD31 and α-SMA.