Enhancing diabetic wound healing through anti-bacterial and promoting angiogenesis using dual-functional slow-release microspheres-loaded dermal scaffolds

Bacterial infections and the degeneration of the capillary network comprise the primary factors that contribute to the delayed healing of diabetic wounds. However, treatment modalities that cater to effective diabetic wounds healing in clinical settings are severely lacking. Herein, a dual-functional microsphere carrier was designed, which encapsulates polyhexamethylene biguanide (PHMB) or recombinant human vascular endothelial growth factor (rhVEGF) together. The in vitro release experiments demonstrated that the use of the microspheres ensured the sustained release of the drugs (PHMB or rhVEGF) over a period of 12 days. Additionally, the integration of these controlled-release microspheres into a dermal scaffold (DS-PLGA@PHMB/rhVEGF) imbued both antibacterial and angiogenic functions to the resulting material. Accordingly, the DS-PLGA@PHMB/rhVEGF scaffold exhibited potent antibacterial properties, effectively suppressing bacterial growth and providing a conducive environment for wound healing, thereby addressing the drawbacks associated with the susceptibility of rhVEGF to deactivation in inflammatory conditions. Additionally, the histological analysis revealed that the use of the DS-PLGA@PHMB/rhVEGF scaffold accelerated the process of wound healing by inhibiting inflammatory reactions, stimulating the production of collagen formation, and enhancing angiogenesis. This provides a novel solution for enhancing the antibacterial and vascularization capabilities of artificial dermal scaffolds, providing a beacon of hope for improving diabetic wound healing.

A bioactive xyloglucan polysaccharide hydrogel mechanically enhanced by Pluronic F127 micelles for promoting chronic wound healing

Chronic wounds represent a formidable global healthcare challenge due to the bacteria infections and uncontrollable inflammation responses, while developing wound healing materials capable of resolving these issues remains a challenge. In this study, we integrated xyloglucan (XG) with Pluronic F127 diacrylate (F127DA)to develop a composite hydrogel for wound healing, where the XG introduced anti-inflammation and anti-bacterial properties to the construct, and F127DA provides the photocurable properties essential for hydrogel formation and robust mechanical characteristics to achieve physical strength that matches tissue regeneration. The material characterizations suggested that XG/F127DA hydrogels had great biostability, blood compatibility and antibacterial effects, which was suitable to be used as a wound healing material. The in vitro analysis by culturing L929 fibroblasts on the hydrogel surface demonstrated that the inclusion of XG could promote the cellular proliferation rate, migration rate, and re-epithelialization-related marker expression, while downregulate the inflammation process. The XG/F127DA hydrogel was further used for the full-thickness skin wound healing test on mice, where the inclusion of XG significantly increased the wound closure rate through reducing the inflammation responses, and promote re-epithelialization and angiogenesis. These results indicated that XG/F127DA hydrogel has great potential to be used for wound healing in future clinical translation.

Hyaluronic Acid/Gelatin-Based Multifunctional Bioadhesive Hydrogel Loaded with a Broad-Spectrum Bacteriocin for Enhancing Diabetic Wound Healing

The development of multifunctional wound adhesives is critical in clinical settings due to the scarcity of dressings with effective adhesive properties while protecting against infection by drug-resistant bacteria. Polysaccharide and gelatin-based hydrogels, known for their biocompatibility and bioactivity, assist in wound healing. This study introduces a multifunctional bioadhesive hydrogel developed through dynamic covalent bonding and light-triggered covalent bonding, comprising oxidized hyaluronic acid, methacrylated gelatin, and the bacteriocin recently discovered by our lab, named jileicin (JC). The adhesion strength of the hydrogel, measured at 180 kPa, was 4.35 times higher than that of the fibrin glue. Furthermore, the hydrogel demonstrated robust platelet adhesion, procoagulant activity, and outstanding hemostatic properties in a mouse liver injury model. Incorporating JC significantly enhanced the phagocytosis and bactericidal capabilities of the macrophages. This immunomodulatory function on host cells, coupled with its potent bacterial membrane-disrupting ability, makes JC an effective killer against methicillin-resistant Staphylococcus aureus. In wound repair experiments on diabetic mice with infected full-thickness skin defects, the hydrogel treatment group showed a notable reduction in bacterial load, accelerated M2-type macrophage polarization, diminished inflammation, and hastened wound healing. Owing to its outstanding biocompatibility, antibacterial activity, and controlled adhesion, this hydrogel presents a promising therapeutic option for treating infected skin wounds.

Bilayer hydrogel with a protective film and a regenerative hydrogel for effective diabetic wound treatment

Diabetic foot ulcers (DFUs) are one of the most serious complications of diabetes, often leading to necrosis and amputation. DFU is caused by the intricate diabetic microenvironment, including ischemia, hypoxia, hyperinflammation, reduced angiogenesis, and persistent infection. Traditional wound dressings made of single or mixed materials often struggle to meet all the requirements for effective diabetic wound healing. In contrast, multilayer dressings comprising more than single layers have the potential to address these challenges by combining their diverse chemical and physical properties. In this study, we developed a bilayer hydrogel comprising a GelMA-ALG-nano-ZnO protective film and a COL1-PRP regenerative hydrogel for facilitating diabetic wound healing. We demonstrated the protective properties against bacterial infection of the protective film, while highlighting the regenerative potential of the COL1-PRP hydrogel in promoting fibroblast and MUVEC migration, extracellular matrix secretion and deposition, and angiogenesis. Importantly, the bilayer hydrogel exhibited superior efficacy in promoting full-thickness wound healing in a diabetic rat model compared to its single-layer hydrogel counterparts. This multi-layer approach offers a promising strategy for addressing the complexities of diabetic foot treatment and improving clinical outcomes.

Cuttlefish ink-derived melanin nanoparticle-embedded tremella fuciformis polysaccharide hydrogels for the treatment of MRSA-infected diabetic wounds

Diabetic wounds arise great attention as they are difficult to heal and easily suffer from serious bacterial infection. However, the overuse of antibiotics increases the resistance of bacteria and makes common drugs ineffective. Here, we developed a photothermal hydrogel (TFP/NP) composed of tremella fuciformis polysaccharides (TFPs) and cuttlefish ink-derived melanin nanoparticles (NPs). The NPs can produce reliable photothermal effects under near-infrared laser (NIR) irradiation and help to remove the bacteria in the wounds, while TFPs were able to form hydrogel frameworks which possessed anti-inflammatory effects and could be applied to promote wound healing. The TFP/NP hydrogels produced stable thermal effects under NIR irradiation and could continuously kill bacteria. The experiment on a full-layer skin wound sMRSA activity and could improve the healing efficiency. The wounds of the mice could be repaired within 14 days after reasonable treatment. In addition, the hydrogels play significant roles in promoting collagen deposition, anti-inflammation, angiogenesis, and cell proliferation during the therapeutic process. This research provides a simple and effective method for the therapy of bacterial infection wounds through the synergistic effect of TFPs and NPs.

Chitosan-based self-healing hydrogel dressing for wound healing

Skin has strong self-regenerative capacity, while severe skin defects do not heal without appropriate treatment. Therefore, in order to cover the wound sites and hasten the healing process, wound dressings are required. Hydrogels have emerged as one of the most promising candidates for wound dressings because of their hydrated and porous molecular structure. Chitosan (CS) with biocompatibility, oxygen permeability, hemostatic and antimicrobial properties is beneficial for wound treatment and it can generate self-healing hydrogels through reversible crosslinks, from dynamic covalent bonding, such as Schiff base bonds, boronate esters, and acylhydrazone bonds, to physical interactions like hydrogen bonding, electrostatic interaction, ionic bonding, metal-coordination, host-guest interactions, and hydrophobic interaction. Therefore, various chitosan-based self-healing hydrogel dressings have been prepared in recent years to cope with increasingly complex wound conditions. This review's objective is to provide comprehensive information on the self-healing mechanism of chitosan-based hydrogel wound dressings, discuss their advanced functions including antibacterial, conductive, anti-inflammatory, anti-oxidant, stimulus-responsive, hemostatic/adhesive and controlled release properties, further introduce their applications in the promotion of wound healing in two categories: acute and chronic (infected, burn and diabetic) wounds, and finally discuss the future perspective of chitosan-based self-healing hydrogel dressings for wound healing.

Unveiling therapeutic potential: Adipose tissue-derived mesenchymal stem cells and their exosomes in the management of diabetes mellitus, wound healing, and chronic ulcers

Diabetes mellitus (DM) is a pervasive global health issue with substantial morbidity and mortality, often resulting in secondary complications, including diabetic wounds (DWs). These wounds, arising from hyperglycemia, diabetic neuropathy, anemia, and ischemia, afflict approximately 15% of diabetic patients, with a considerable 25% at risk of lower limb amputations. The conventional approaches for chronic and diabetic wounds management involves utilizing various therapeutic substances and techniques, encompassing growth factors, skin substitutes and wound dressings. In parallel, emerging cell therapy approaches, notably involving adipose tissue-derived mesenchymal stem cells (ADMSCs), have demonstrated significant promise in addressing diabetes mellitus and its complications. ADMSCs play a pivotal role in wound repair, and their derived exosomes have garnered attention for their therapeutic potential. This review aimed to unravel the potential mechanisms and provide an updated overview of the role of ADMSCs and their exosomes in diabetes mellitus and its associated complications, with a specific focus on wound healing.

Long duration sodium hyaluronate hydrogel with dual functions of both growth prompting and acid-triggered antibacterial activity for bacteria-infected wound healing

Conventional wound dressings are monolithically designed to cover the injured areas as well as absorb the exudates at injured site. Furthermore, antibacterial drugs and growth prompting factors are additionally appended to realize sensible and omnibearing wound management, exhibiting long and tedious treatment process in practice. Consequently, the creation of multifunctional wound dressings that combines wound repair enhancement with antibacterial properties turns out to be significant for simplifying wound managements. In our investigation, electronegative human epidermal growth factor (hEGF) was combined with the positively charged Zn-Al layered double hydroxides (Zn-Al LDHs) via electrostatic interaction while the obtained hEGF/LDH was integrated with sodium hyaluronate hydrogel (SH) hydrogel, forming a composite hydrogel with synergistic benefits for wound management. The innovative hEGF/LDH@SH hydrogel equipped with fine biocompatibility was designed to optimize wound healing in which hEGF stimulates epithelial cell growth while LDH released antibacterial factor Zn2+ against Methicillin-resistant staphylococcus aureus (MRSA) and Escherichia coli (E.coli) under acidic wound environment. Additionally, the SH hydrogel constructed a three-dimensional structure that not only safeguarded the wound area but also maintained a moist environment conducive to recovery. The synthesized hEGF/LDH was confirmed via fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermo-gravimetry (TG) measurements. The release of Zn2+ from Zn-Al LDH under acid circumstance was detected via inductively coupled plasma (ICP) and the in vitro bactericidal experiments endowed the antibacterial property of hEGF/LDH@SH hydrogel. In vitro drug release experiments illustrated the controlled-release of hEGF from hEGF/LDH which promoted the long-term affect of hEGF at wound site. In vitro cell experiments verified that the hEGF/LDH@SH hydrogel motivated the promotion on cell proliferation and migration without cytotoxicity. An in vivo study of the repairing of MRSA-infected wound in mice indicated that hEGF/LDH@SH hydrogel serves as a simple and novel, innoxious and efficient wound healing approach. This brand new hydrogel possesses properties of promoting the regeneration of skin tissue, achieving antimicrobial therapy without any accessional antibacterial drugs as well as realizing controlled release of hEGF.

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.

Development and characterization of ferulic acid-loaded chitosan nanoparticle embedded- hydrogel for diabetic wound delivery

Diabetic wounds present a significant global health challenge exacerbated by chronic hyperglycemia-induced oxidative stress, impeding the natural healing process. Despite various treatment strategies, diabetic foot ulceration lacks standardized therapy. Ferulic acid (FA), known for its potent antidiabetic and antioxidant properties, holds promise for diabetic wound management. However, oral administration of FA faces limitations due to rapid oxidation, stability issues, and low bioavailability. The topical application of FA-loaded chitosan nanoparticles (FA-CSNPs) has emerged as a promising approach to overcome these challenges. Here, we report the development of a sustained-release formulation of FA-CSNPs within a hydrogel matrix composed of Chitosan and gelatin. The FA-CSNPs were synthesized using the ionic gelation method andoptimized through a Central Composite Design (CCD) approach. Characterization of the optimized nanoparticles revealed spherical morphology, a particle size of 56.9 ± 2.5 nm, and an impressive entrapment efficiency of 90.3 ± 2.4 %. Subsequently, an FA-CSNPs-loaded hydrogel was formulated, incorporating chitosan as a gelling agent, gelatin to enhance mechanical properties and cell permeation, and glutaraldehyde as a cross-linker. Comprehensive characterization of the hydrogel included pH, moisture loss, porosity, swelling index, rheology, water vapor transmission rate (WVTR), SEM, TEM, invitro drug release studies, antioxidant activity, antibacterial efficacy, cell cytotoxicity, cell migration studies on L929 fibroblast cell line, and stability studies. The stability study demonstrated negligible variations in particle size, zeta potential, and entrapment efficiency over 60 days, ensuring the stable nature of nanoparticles and hydrogel. This innovative delivery approach embedded within a hydrogel matrix holds significant promise for enhancing the therapeutic efficacy of FA-CSNPs-hydrogel in diabetic wound healing applications.

Deep Red Light Driven Hydrogen Evolution by Heterojunction Polymer Dots for Diabetic Wound Healing

We describe small heterojunction polymer dots (Pdots) with deep-red light catalyzed H2 generation for diabetic skin wound healing. The Pdots with donor/acceptor heterojunctions showed remarkably enhanced photocatalytic activity as compared to the donor or acceptor nanoparticles alone. We encapsulate the Pdots and ascorbic acid into liposomes to form Lipo-Pdots nanoreactors, which selectively scavenge ⋅OH radicals in live cells and tissues under 650 nm light illumination. The antioxidant capacity of the heterojunction Pdots is ~10 times higher than that of the single-component Pdots described previously. Under a total light dose of 360 J/cm2, the Lipo-Pdots nanoreactors effectively scavenged ⋅OH radicals and suppressed the expression of pro-inflammatory cytokines in skin tissues, thereby accelerating the healing of skin wounds in diabetic mice. This study provides a feasible solution for safe and effective treatment of diabetic foot ulcers.

A Hemoglobin Bionics-Based System for Combating Antibiotic Resistance in Chronic Diabetic Wounds via Iron Homeostasis Regulation

Owing to the increased tissue iron accumulation in patients with diabetes, microorganisms may activate high expression of iron-involved metabolic pathways, leading to the exacerbation of bacterial infections and disruption of systemic glucose metabolism. Therefore, an on-demand transdermal dosing approach that utilizes iron homeostasis regulation to combat antimicrobial resistance is a promising strategy to address the challenges associated with low administration bioavailability and high antibiotic resistance in treating infected diabetic wounds. Here, it is aimed to propose an effective therapy based on hemoglobin bionics to induce disturbances in bacterial iron homeostasis. The preferred "iron cargo" is synthesized by protoporphyrin IX chelated with dopamine and gallium (PDGa), and is delivered via a glucose/pH-responsive microneedle bandage (PDGa@GMB). The PDGa@GMB downregulates the expression levels of the iron uptake regulator (Fur) and the peroxide response regulator (perR) in Staphylococcus aureus, leading to iron nutrient starvation and oxidative stress, ultimately suppressing iron-dependent bacterial activities. Consequently, PDGa@GMB demonstrates insusceptibility to genetic resistance while maintaining sustainable antimicrobial effects (>90%) against resistant strains of both S. aureus and E. coli, and accelerates tissue recovery (<20 d). Overall, PDGa@GMB not only counteracts antibiotic resistance but also holds tremendous potential in mediating microbial-host crosstalk, synergistically attenuating pathogen virulence and pathogenicity.

NIR-responsive electrospun nanofiber dressing promotes diabetic-infected wound healing with programmed combined temperature-coordinated photothermal therapy

BACKGROUND

Diabetic wounds present significant challenges, specifically in terms of bacterial infection and delayed healing. Therefore, it is crucial to address local bacterial issues and promote accelerated wound healing. In this investigation, we utilized electrospinning to fabricate microgel/nanofiber membranes encapsulating MXene-encapsulated microgels and chitosan/gelatin polymers.

RESULTS

The film dressing facilitates programmed photothermal therapy (PPT) and mild photothermal therapy (MPTT) under near-infrared (NIR), showcasing swift and extensive antibacterial and biofilm-disrupting capabilities. The PPT effect achieves prompt sterilization within 5 min at 52 °C and disperses mature biofilm within 10 min. Concurrently, by adjusting the NIR power to induce local mild heating (42 °C), the dressing stimulates fibroblast proliferation and migration, significantly enhancing vascularization. Moreover, in vivo experimentation successfully validates the film dressing, underscoring its immense potential in addressing the intricacies of diabetic wounds.

CONCLUSIONS

The MXene microgel-loaded nanofiber dressing employs temperature-coordinated photothermal therapy, effectively amalgamating the advantageous features of high-temperature sterilization and low-temperature promotion of wound healing. It exhibits rapid, broad-spectrum antibacterial and biofilm-disrupting capabilities, exceptional biocompatibility, and noteworthy effects on promoting cell proliferation and vascularization. These results affirm the efficacy of our nanofiber dressing, highlighting its significant potential in addressing the challenge of diabetic wounds struggling to heal due to infection.

Advances in skin gene therapy: utilizing innovative dressing scaffolds for wound healing, a comprehensive review

The skin, serving as the body's outermost layer, boasts a vast area and intricate structure, functioning as the primary barrier against external threats. Disruptions in the composition and functionality of the skin can lead to a diverse array of skin conditions, such as wounds, burns, and diabetic ulcers, along with inflammatory disorders, infections, and various types of skin cancer. These disorders not only exacerbate concerns regarding skin health and beauty but also have a significant impact on mental well-being. Due to the complexity of these disorders, conventional treatments often prove insufficient, necessitating the exploration of new therapeutic approaches. Researchers develop new therapies by deciphering these intricacies and gaining a thorough understanding of the protein networks and molecular processes in skin. A new window of opportunity has opened up for improving wound healing processes because of recent advancements in skin gene therapy. To enhance skin regeneration and healing, this extensive review investigates the use of novel dressing scaffolds in conjunction with gene therapy approaches. Scaffolds that do double duty as wound protectors and vectors for therapeutic gene delivery are being developed using innovative biomaterials. To improve cellular responses and speed healing, these state-of-the-art scaffolds allow for the targeted delivery and sustained release of genetic material. The most recent developments in gene therapy techniques include RNA interference, CRISPR-based gene editing, and the utilization of viral and non-viral vectors in conjunction with scaffolds, which were reviewed here to overcome skin disorders and wound complications. In the future, there will be rare chances to develop custom methods for skin health care thanks to the combination of modern technology and collaboration among disciplines.

Renewable Electroconductive Hydrogels for Accelerated Diabetic Wound Healing and Motion Monitoring

Diabetic foot ulcers (DFUs), a prevalent complication of diabetes mellitus, may result in an amputation. Natural and renewable hydrogels are desirable materials for DFU dressings due to their outstanding biosafety and degradability. However, most hydrogels are usually only used for wound repair and cannot be employed to monitor motion because of their inherent poor mechanical properties and electrical conductivity. Given that proper wound stretching is beneficial for wound healing, the development of natural hydrogel patches integrated with wound repair properties and motion monitoring was expected to achieve efficient and accurate wound healing. Here, we designed a dual-network (chitosan and sodium alginate) hydrogel embedded with lignin-Ag and quercetin-melanin nanoparticles to achieve efficient wound healing and motion monitoring. The double network formed by the covalent bond and electrostatic interaction confers the hydrogel with superior mechanical properties. Instead of the usual chemical reagents, genipin extracted from Gardenia was used as a cross-linking agent for the hydrogel and consequently improved its biosafety. Furthermore, the incorporation of lignin-Ag nanoparticles greatly enhanced the mechanical strength, antibacterial efficacy, and conductivity of the hydrogel. The electrical conductivity of hydrogels gives them the capability of motion monitoring. The motion sensing mechanism is that stretching of the hydrogel induced by motion changes the conductivity of the hydrogel, thus converting the motion into an electrical signal. Meanwhile, quercetin-melanin nanoparticles confer exceptional adhesion, antioxidant, and anti-inflammatory properties to the hydrogels. The system ultimately achieved excellent wound repair and motion monitoring performance and was expected to be used for stretch-assisted safe and accurate wound repair in the future.

All-in-one hydrogel patches with sprayed bFGF-loaded GelMA microspheres for infected wound healing studies

The current wound healing process faces numerous challenges such as bacterial infection, inflammation and oxidative stress. However, wound dressings used to promote wound healing, are not well suited to meet the clinical needs. Hyaluronic acid (HA) not only has excellent water absorption and good biocompatibility but facilitates cell function and tissue regeneration. Dopamine, on the other hand, increases the overall viscosity of the hydrogel and possesses antioxidant property. Furthermore, chitosan exhibits outstanding performance in antimicrobial, anti-inflammatory and antioxidant activities. Basic fibroblast growth factor (bFGF) is conducive to cell proliferation and migration, vascular regeneration and wound healing. Hence, we designed an all-in-one hydrogel patch containing dopamine and chitosan framed by hyaluronic acid (HDC) with sprayed gelatin methacryloyl (GelMA) microspheres loaded with bFGF (HDC-bFGF). The hydrogel patch exhibits excellent adhesive, anti-inflammatory, antioxidant and antibacterial properties. In vitro experiments, the HDC-bFGF hydrogel patch not only showed significant inhibitory effect on RAW cell inflammation and Staphylococcus aureus (S. aureus) growth but also effectively scavenged free radicals, in addition to promoting the migration of 3 T3 cells. In the mice acute infected wound model, the HDC-bFGF hydrogel patch adhered to the wound surface greatly accelerated the healing process via its anti-inflammatory and antioxidant activities, bacterial inhibition and pro-vascularization effects. Therefore, the multifunctional HDC-bFGF hydrogel patch holds great promise for clinical application.

Stretch-Induced Conductivity Enhancement in Highly Conductive and Tough Hydrogels

The resistance of gels and elastomers increases significantly with tensile strain, which reduces conductive stability and restricts their use in stable and reliable electronics. Here, highly conductive tough hydrogels composed of silver nanowires (AgNWs), liquid metal (LM), and poly(vinyl alcohol) (PVA) are fabricated. The stretch-induced orientations of AgNWs, deformable LM, and PVA nanocrystalline create conductive pathways, enhancing the mechanical properties of the hydrogels, including increased ultimate fracture stress (13-33 MPa), strain (3000-5300%), and toughness (390.9-765.1 MJ m-3). Notably, the electrical conductivity of the hydrogels is significantly improved from 4.05 × 10-3 to 24 S m-1 when stretched to 4200% strain, representing a 6000-fold enhancement. The incorporation of PVA nanocrystalline, deformable LM, and AgNWs effectively mitigates stress concentration at the crack tip, thereby conferring crack propagation insensitivity and fatigue resistance to the hydrogels. Moreover, the hydrogels are designed with a reversible crosslinking network, allowing for water-induced recycling.

Edge-functionalized coal-derived graphene oxide in bacterial nanocellulose hydrogel for active wound healing

This work presents a comparison of physicochemical and in vitro active wound healing properties of two distinct Graphene Oxides (GOs) from graphite and coal. These GOs are incorporated in Bacterial Nanocellulose (BNC) to form hydrogels. The performance and limitations of the loading fraction of both GOs in BNC are controlled by the processing technology and the source materials from which GOs are derived. Edge functionalization with C-GO offers the advantage of facilitating face-to-edge assembly in the hydrogel leading to better dispersion than the face-to-face assembly of basal functionalized G-GO. The latter leads to more aggregation of G-GO, resulting in a lower optimal loading fraction. Our investigation into the antibacterial properties of the BNC and BNC/GO hydrogels against gram-negative E. coli revealed inhibitory effects of the BNC/GO hydrogels that intensified with an increase in the concentration of GO. Furthermore, an in vitro wound scratch assay demonstrated that BNC/C-GO hydrogels promote better cell migration, confirming their superior biocompatibility and suitability as active wound dressings, albeit limited by loading fraction due to agglomeration. These findings shed light on the performance and limitations of GOs for diverse applications, emphasizing the significance of exploring the influence of different methods and source materials of GOs.

Micro-environment triple-responsive hyaluronic acid hydrogel dressings to promote antibacterial activity, collagen deposition, and angiogenesis for diabetic wound healing

The clinical treatment of chronic diabetic wounds is a long-standing thorny issue. Strategies targeting the diabetic micro-environment have been developed to promote wound healing. However, it remains challenging to reverse the adverse conditions and re-activate tissue regeneration and angiogenesis. In this work, we develop injectable hydrogels that are responsive to acidic conditions, reactive oxygen species (ROS), and high glucose levels in a diabetic wound micro-environment to sustainably deliver tannic acid (TA) to augment antibacterial, anti-inflammatory, and anti-oxidative activities. This triple-responsive mechanism is designed by introducing dynamic acylhydrazone and phenylboronic ester bonds to crosslink modified hyaluronic acid (HA) chains. At a diabetic wound, the acylhydrazone bonds may be hydrolyzed at low pH. Meanwhile, glucose may compete with TA, and ROS may oxidize the C-B bond to release TA. Thus, sustained release of TA is triggered by the diabetic micro-environment. The released TA effectively scavenges ROS and kills bacteria. In vivo experiments on diabetic mice demonstrate that the hydrogel dressing highly promotes angiogenesis and extracellular matrix (ECM) deposition, leading to eventual full healing of diabetic skin wounds. This micro-environment-triggered triple-responsive drug release provides a promising method for chronic diabetic wound healing.

Infection-Free and Enhanced Wound Healing Potential of Alginate Gels Incorporating Silver and Tannylated Calcium Peroxide Nanoparticles

The treatment of chronic wounds involves precise requirements and complex challenges, as the healing process cannot go beyond the inflammatory phase, therefore increasing the healing time and implying a higher risk of opportunistic infection. Following a better understanding of the healing process, oxygen supply has been validated as a therapeutic approach to improve and speed up wound healing. Moreover, the local implications of antimicrobial agents (such as silver-based nano-compounds) significantly support the normal healing process, by combating bacterial contamination and colonization. In this study, silver (S) and tannylated calcium peroxide (CaO2@TA) nanoparticles were obtained by adapted microfluidic and precipitation synthesis methods, respectively. After complementary physicochemical evaluation, both types of nanoparticles were loaded in (Alg) alginate-based gels that were further evaluated as possible dressings for wound healing. The obtained composites showed a porous structure and uniform distribution of nanoparticles through the polymeric matrix (evidenced by spectrophotometric analysis and electron microscopy studies), together with a good swelling capacity. The as-proposed gel dressings exhibited a constant and suitable concentration of released oxygen, as shown for up to eight hours (UV-Vis investigation). The biofilm modulation data indicated a synergistic antimicrobial effect between silver and tannylated calcium peroxide nanoparticles, with a prominent inhibitory action against the Gram-positive bacterial biofilm after 48 h. Beneficial effects in the human keratinocytes cultured in contact with the obtained materials were demonstrated by the performed tests, such as MTT, LDH, and NO.

A Multifunctional Hydrogel Fabricated by Direct Self-Assembly of Natural Herbal Small Molecule Mangiferin for Treating Diabetic Wounds

Clinical studies have continually referred to the involvement of drug carrier having dramatic negative influences on the biocompatibility, biodegradability, and loading efficacy of hydrogel. To overcome this deficiency, researchers have proposed to directly self-assemble natural herbal small molecules into a hydrogel without any structural modification. However, it is still a formidable challenge due to the high requirements on the structure of natural molecules, leading to a rarity of this type of hydrogel. Mangiferin (MF) is a natural polyphenol of C-glucoside xanthone with various positive health benefits, including the treatment of diabetic wounds, but its poor hydrosolubility and low bioavailability significantly restrict the clinical application. Inspired by these, with heating/cooling treatment, a carrier-free hydrogel (MF-gel) is developed by assembling the natural herbal molecule mangiferin, which is mainly governed through hydrogen bonds and intermolecular π-π stacking interactions. The as-prepared hydrogel has injectable and self-healing properties and shows excellent biocompatibility, continuous release ability, and reversible stimuli-responsive performances. All of the superiorities enable the MF-based hydrogel to serve as a potential wound dressing for treating diabetic wounds, which was further confirmed by both the vitro and vivo studies. In vitro, the MF-gel could promote the migration of healing-related cells from peripheral as well as the angiogenesis and displays the capacity of mediating inflammation response by scavenging the intracellular ROS. In vivo, the MF-gel accelerates wound contraction and healing via inflammatory adjustment, collagen deposition, and angiogenesis. This study provides a facile and effective method for diabetic wound management and emphasizes the direct self-assembly hydrogel from natural herbal small molecule.

Functional biomacromolecules-based microneedle patch for the treatment of diabetic wound

Diabetic wounds are a common complication of diabetes. The prolonged exposure to high glucose and oxidative stress in the wound environment increases the risk of bacterial infection and abnormal angiogenesis, leading to amputation. Microneedle patches have shown promise in promoting the healing of diabetic wounds through transdermal drug delivery. These patches target the four main aspects of diabetic wound treatment: hypoglycemia, antibacterial action, inflammatory regulation, and tissue regeneration. By overcoming the limitations of traditional administration methods, microneedle patches enable targeted therapy for deteriorated tissues. The design of these patches extends beyond the selection of needle tip material and biomacromolecule encapsulated drugs; it can also incorporate near-infrared rays to facilitate cascade reactions and treat diabetic wounds. In this review, we comprehensively summarize the advantages of microneedle patches compared to traditional treatment methods. We focus on the design and mechanism of these patches based on existing experimental articles in the field and discuss the potential for future research on microneedle patches.

The Combination of Bioactive Herbal Compounds with Biomaterials for Regenerative Medicine

Regenerative medicine aims to restore the function of diseased or damaged tissues and organs by cell therapy, gene therapy, and tissue engineering, along with the adjunctive application of bioactive molecules. Traditional bioactive molecules, such as growth factors and cytokines, have shown great potential in the regulation of cellular and tissue behavior, but have the disadvantages of limited source, high cost, short half-life, and side effects. In recent years, herbal compounds extracted from natural plants/herbs have gained increasing attention. This is not only because herbal compounds are easily obtained, inexpensive, mostly safe, and reliable, but also owing to their excellent effects, including anti-inflammatory, antibacterial, antioxidative, proangiogenic behavior and ability to promote stem cell differentiation. Such effects also play important roles in the processes related to tissue regeneration. Furthermore, the moieties of the herbal compounds can form physical or chemical bonds with the scaffolds, which contributes to improved mechanical strength and stability of the scaffolds. Thus, the incorporation of herbal compounds as bioactive molecules in biomaterials is a promising direction for future regenerative medicine applications. Herein, an overview on the use of bioactive herbal compounds combined with different biomaterial scaffolds for regenerative medicine application is presented. We first introduce the classification, structures, and properties of different herbal bioactive components and then provide a comprehensive survey on the use of bioactive herbal compounds to engineer scaffolds for tissue repair/regeneration of skin, cartilage, bone, neural, and heart tissues. Finally, we highlight the challenges and prospects for the future development of herbal scaffolds toward clinical translation. Overall, it is believed that the combination of bioactive herbal compounds with biomaterials could be a promising perspective for the next generation of regenerative medicine.

Sprayable Zwitterionic Antibacterial Hydrogel With High Mechanical Resilience and Robust Adhesion for Joint Wound Treatment

Wound healing in movable parts, including the joints and neck, remains a critical challenge due to frequent motions and poor flexibility of dressings, which may lead to mismatching of mechanical properties and poor fitting between dressings and wounds; thus, increasing the risk of bacterial infection. This study proposes a sprayable zwitterionic antibacterial hydrogel with outstanding flexibility and desirable adhesion. This hydrogel precursor is fabricated by combining zwitterionic sulfobetaine methacrylate (SBMA) with poly(sulfobetaine methacrylate-co-dopamine methacrylamide)-modified silver nanoparticles (PSBDA@AgNPs) through robust electrostatic interactions. About 150 s of exposure to UV light, the SBMA monomer polymerizes to form PSB chains entangled with PSBDA@AgNPs, transformed into a stable and adhesion PSB-PSB@Ag hydrogel at the wound site. The resulting hydrogel has adhesive strength (15-38 kPa), large tensile strain (>400%), suitable shape adaptation, and excellent mechanical resilience. Moreover, the hydrogel displays pH-responsive behavior; the acidic microenvironment at the infected wound sites prompts the hydrogel to rapidly release AgNPs and kill bacteria. Further, the healing effect of the hydrogel is demonstrated on the rat neck skin wound, showing improved wound closing rate due to reduced inflammation and enhanced angiogenesis. Overall, the sprayable zwitterionic antibacterial hydrogel has significant potential to promote joint skin wound healing.

Novel ray of hope for diabetic wound healing: Hydrogen sulfide and its releasing agents

BACKGROUND

Diabetes mellitus (DM) is a long-term metabolic disease accompanied by difficulties in wound healing placing a severe financial and physical burden on patients. As one of the important signal transduction molecules, both endogenous and exogenous hydrogen sulfide (H2S) was found to promote diabetic wound healing in recent studies. H2S at physiological concentrations can not only promote cell migration and adhesion functions, but also resist inflammation, oxidative stress and inappropriate remodeling of the extracellular matrix.

AIM OF REVIEW

The purpose of this review is to summarize current research on the function of H2S in diabetic wound healing at all stages, and propose future directions.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this review, first, the various factors affecting wound healing under diabetic pathological conditions and the in vivo H2S generation pathway are briefly introduced. Second, how H2S may improve diabetic wound healing is categorized and described. Finally, we discuss the relevant H2S donors and new dosage forms, analyze and reveal the characteristics of many typical H2S donors, which may provide new ideas for the development of H2S-released agents 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.

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.

A Printable Hydrogel Loaded with Medicinal Plant Extract for Promoting Wound Healing

How to promote wound healing is still a major challenge in the healthcare while macrophages are a critical component of the healing process. Compared to various bioactive drugs, many plants have been reported to facilitate the wound healing process by regulating the immune response of wounds. In this work, a Three-dimensional (3D) printed hydrogel scaffold loaded with natural Centella asiatica extract (CA extract) is developed for wound healing. This CA@3D scaffold uses gelatin (Gel) and sodium alginate (SA) with CA extract as bio-ink for 3D printing. The CA extract contains a variety of bioactive compounds that make the various active ingredients in Centella asiatica work in concert. The printed CA@3D scaffold can fit the shape of wound, orchestrate the macrophages and immune responses within the wound, and promote wound healing compared to commercial wound dressings. The underlying mechanism of promoting wound healing is also illuminated by applying multi-omic analyses. Moreover, the CA extract loaded 3D scaffold also showed great ability to promote wound healing in diabetic chronic wounds. Due to its ease of preparation, low-cost, biosafety, and therapeutic outcomes, this work proposes an effective strategy for promoting chronic wound healing.

Porous Collagen Sponge Loaded with Large Efficacy-Potentiated Exosome-Mimicking Nanovesicles for Diabetic Skin Wound Healing

Diabetic skin wounds are difficult to heal quickly due to insufficient angiogenesis and prolonged inflammation, which is an urgent clinical problem. To address this clinical problem, it becomes imperative to develop a dressing that can promote revascularization and reduce inflammation during diabetic skin healing. Herein, a multifunctional collagen dressing (CTM) was constructed by loading large efficacy-potentiated exosome-mimicking nanovesicles (L-Meseomes) into a porous collagen sponge with transglutaminase (TGase). L-Meseomes were constructed in previous research with the function of promoting cell proliferation, migration, and angiogenesis and inhibiting inflammation. CTM has a three-dimensional porous network structure with good biocompatibility, swelling properties, and degradability and could release L-Meseome slowly. In vitro experiments showed that CTM could promote the proliferation of fibroblasts and the polarization of macrophages to the anti-inflammatory phenotype. For in vivo experiments, on the 21st day after surgery, the wound healing rates of the control and CTM were 83.026 ± 4.17% and 93.12 ± 2.16%, respectively; the epidermal maturation and dermal differentiation scores in CTM were approximately four times that of the control group, and the skin epidermal thickness of the CTM group was approximately 20 μm, which was closest to that of normal rats. CTM could significantly improve wound healing in diabetic rats by promoting anti-inflammation, angiogenesis, epidermal recovery, and dermal collagen deposition. In summary, the multifunctional collagen dressing CTM could significantly promote the healing of diabetic skin wounds, which provides a new strategy for diabetic wound healing in the clinic.

Insights into the mechanisms of diabetic wounds: pathophysiology, molecular targets, and treatment strategies through conventional and alternative therapies

Diabetes mellitus is a prevalent cause of mortality worldwide and can lead to several secondary issues, including DWs, which are caused by hyperglycemia, diabetic neuropathy, anemia, and ischemia. Roughly 15% of diabetic patient's experience complications related to DWs, with 25% at risk of lower limb amputations. A conventional management protocol is currently used for treating diabetic foot syndrome, which involves therapy using various substances, such as bFGF, pDGF, VEGF, EGF, IGF-I, TGF-β, skin substitutes, cytokine stimulators, cytokine inhibitors, MMPs inhibitors, gene and stem cell therapies, ECM, and angiogenesis stimulators. The protocol also includes wound cleaning, laser therapy, antibiotics, skin substitutes, HOTC therapy, and removing dead tissue. It has been observed that treatment with numerous plants and their active constituents, including Globularia Arabica, Rhus coriaria L., Neolamarckia cadamba, Olea europaea, Salvia kronenburgii, Moringa oleifera, Syzygium aromaticum, Combretum molle, and Myrtus communis, has been found to promote wound healing, reduce inflammation, stimulate angiogenesis, and cytokines production, increase growth factors production, promote keratinocyte production, and encourage fibroblast proliferation. These therapies may also reduce the need for amputations. However, there is still limited information on how to prevent and manage DWs, and further research is needed to fully understand the role of alternative treatments in managing complications of DWs. The conventional management protocol for treating diabetic foot syndrome can be expensive and may cause adverse side effects. Alternative therapies, such as medicinal plants and green synthesis of nano-formulations, may provide efficient and affordable treatments for DWs.

A highly stretchable, adhesive, and antibacterial hydrogel with chitosan and tobramycin as dynamic cross-linkers for treating the infected diabetic wound

Diabetic wounds pose a significant challenge due to their susceptibility to bacterial infection in a high-glucose environment, which impedes the wound healing process. To address this issue, there is a pressing need to develop suitable hydrogels that can promote the regeneration of diabetic wounds in clinical practice. In this study, we designed and fabricated a highly stretchable, adhesive, transparent, and antibacterial hydrogel through a one-pot radical polymerization of N-[Tris (hydroxymethyl) methyl] acrylamide (THMA) and acrylic acid (AA), and with chitosan and the antibiotic tobramycin as the dynamic physical crosslinkers. The copolymer contains a large number of carboxyl and hydroxyl groups, which can form an interpenetrating network structure with chitosan and tobramycin through multiple dynamic non-covalent bonds. This hydrogel exhibited over 1600 % elongation through an energy dissipation mechanism and strong adhesion to various surfaces without any chemical reaction. In vivo, studies conducted on a staphylococcus aureus-infected full-thickness diabetic skin wound model demonstrated that the hydrogel loaded with tobramycin as one of the crosslinkers had a long-lasting antibacterial activity and effectively accelerated wound healing. Therefore, the antibiotic-loaded adhesive hydrogel we proposed holds great promise as a treatment for bacteria-infected diabetic wounds.

Multifunctional Hydrogels for the Healing of Diabetic Wounds

The healing of diabetic wounds is hindered by various factors, including bacterial infection, macrophage dysfunction, excess proinflammatory cytokines, high levels of reactive oxygen species, and sustained hypoxia. These factors collectively impede cellular behaviors and the healing process. Consequently, this review presents intelligent hydrogels equipped with multifunctional capacities, which enable them to dynamically respond to the microenvironment and accelerate wound healing in various ways, including stimuli -responsiveness, injectable self-healing, shape -memory, and conductive and real-time monitoring properties. The relationship between the multiple functions and wound healing is also discussed. Based on the microenvironment of diabetic wounds, antibacterial, anti-inflammatory, immunomodulatory, antioxidant, and pro-angiogenic strategies are combined with multifunctional hydrogels. The application of multifunctional hydrogels in the repair of diabetic wounds is systematically discussed, aiming to provide guidelines for fabricating hydrogels for diabetic wound healing and exploring the role of intelligent hydrogels in the therapeutic processes.

Network Pharmacology Study on Herb Pair Bletilla striata-Galla chinensis in the Treatment of Chronic Skin Ulcers

BACKGROUND

Herb pair Bletilla striata-Galla chinensis (BS-GC) is a classic combination of topical traditional Chinese medicine formulae in the treatment of chronic skin ulcers (CSUs).

OBJECTIVE

The aim of this study is to explore the effective active ingredients of BS-GC, as well as the core targets and signal transduction pathways of its action on CSUs.

METHODS

The ingredients of BS-GC were obtained from TCMSP and HERB databases. The targets of all active ingredients were retrieved from the SwissTargetPrediction database. The targets of CSUs were obtained from OMIM, GeneCards, Drugbank, and DisGeNET databases. A drug-disease target protein-protein interaction (PPI) network was constructed to select the most core targets, and an herb-ingredient-target network was built by utilizing Cytoscape 3.7.2. Furthermore, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes database (KEGG) analysis and verified the results of network pharmacology through molecular docking.

RESULTS

A total of 40 active ingredients from the herb pair BS-GC were initially screened, and a total of 528 targets were retrieved. Meanwhile, the total number of CSU targets was 1032. Then, the number of common targets between BS-GC and CSUs was 107. The 13 core targets of herb pair BS-GC with CSUs were filtered out according to the PPI network, including AKT1, TNF, EGFR, BCL2, HIF1A, MMP-9, etc. The 5 main core active ingredients were 1-(4-Hydroxybenzyl)-2-methoxy-9,10-dihydrophenanthrene-4,7-diol, 1-(4- Hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene-2,7-diol, physcion, dihydromyricetin, and myricetin. The main biological processes were inflammation, oxidative stress, and immune response, involving the AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, NF-κB signaling pathway, and calcium signaling pathway. Molecular docking results showed good binding activity between the 5 main core active ingredients and 13 core targets.

CONCLUSION

This study predicted the core targets and signal transduction pathways in the treatment of CSUs to provide a reference for further molecular mechanism research.

Local Delivery of Glabridin by Biomolecular Microneedle to Accelerate Infected Wound Healing

Applying antibacterial polymers and pro-regenerative small molecules are two individual strategies for accelerating wound healing. However, integrating those two unique approaches into one therapeutic platform that meets clinical requirements is still a challenge. Herein, a series of antibacterial gelatin methacrylate (GelMA)/ε-polylysine (ε-PL) composite hydrogels (termed as GP-n HGs, n = 0, 10, 20, and 30, respectively) are innovatively fabricated by ultraviolet light (UV) crosslinking. The GP-n HGs are proved to be broad-spectrum antibacterial and biocompatible. Among those GP-n HGs, the GP-20 HG is selectively processed into microneedle following a mold-casting method. Then, the glabridin is loaded into those needles to produce composite microneedle termed GP-20@Gla MN. An S. aureus-infected full-thickness defect model in rats is created to evaluate the wound-healing effect of GP-20@Gla MN. Furthermore, an RNA sequencing assay is performed to explore the possible molecular mechanisms of glabridin in promoting tissue regeneration, and many positive routes are summarized. This work is of significant novelty in fulfilling complex clinical needs by simultaneously optimizing the advanced microneedles' chemical compositions and physical structures. This work will provide a promising therapeutic platform for treating infected and chronic wounds.

Immunomodulation in diabetic wounds healing: The intersection of macrophage reprogramming and immunotherapeutic hydrogels

Diabetic wound healing presents a significant clinical challenge due to the interplay of systemic metabolic disturbances and local inflammation, which hinder the healing process. Macrophages undergo a phenotypic shift from M1 to M2 during wound healing, a transition pivotal for effective tissue repair. However, in diabetic wounds, the microenvironment disrupts this phenotypic polarization, perpetuating inflammation, and impeding healing. Reprograming macrophages to restore their M2 phenotype offers a potential avenue for modulating the wound immune microenvironment and promoting healing. This review elucidates the mechanisms underlying impaired macrophage polarization toward the M2 phenotype in diabetic wounds and discusses novel strategies, including epigenetic and metabolic interventions, to promote macrophage conversion to M2. Hydrogels, with their hydrated 3D cross-linked structure, closely resemble the physiological extracellular matrix and offer advantageous properties such as biocompatibility, tunability, and versatility. These characteristics make hydrogels promising candidates for developing immunomodulatory materials aimed at addressing diabetic wounds. Understanding the role of hydrogels in immunotherapy, particularly in the context of macrophage reprograming, is essential for the development of advanced wound care solutions. This review also highlights recent advancements in immunotherapeutic hydrogels as a step toward precise and effective treatments for diabetic wounds.

Charged Fibrous Dressing to Promote Diabetic Chronic Wound Healing

Diabetic chronic wounds cause a significant amount of pain to patients because of their low cure rates and high recurrence rates. Traditional approaches to treating diabetic chronic wounds often involve the delivery of drugs or cytokines that regulate the microenvironment and eliminate bacterial infection in the wound area, but they are passive in controlling cell behaviors and may lead to drug resistance. Emerging drug-free wound treatments are important for convenient, effective, and safe treatment strategies. However, the current approaches cannot fully promote tissue regeneration or prevent bacterial infections. Here, the efficacy of a negatively charged fiber dressing in promoting diabetic chronic wound healing is investigated. The negatively charged fiber dressing can generate reactive oxygen species to inhibit bacterial reproduction with the assistance of ultrasound during the inflammatory phase. Furthermore, the dressing provides an electrostatic field that regulates cellular behavior during the inflammatory and proliferative phases. In particular, the dressing can promote fibroblast migration and induce macrophage polarization and neovascularization without any additional drugs. It is demonstrated that this strategy enables the healing of diabetic chronic wounds in a mouse model, achieving effective wound closure over a 12-day treatment cycle and providing a drug-free therapeutic strategy for diabetic chronic wound care.

Bioactive self-healing umbilical cord blood exosomes hydrogel for promoting chronic diabetic wound healing

The deleterious effects of diabetes mellitus on wound healing have become a major public health concern worldwide. Given the complex microenvironment of diabetic wounds and the high prevalence of diabetes, the design and development of novel wound dressing materials with versatile capabilities is urgent. Extracellular vesicles (EVs) derived from human umbilical cord blood have demonstrated the potential to counter inflammation and accelerate wound healing. Herein, we explored the efficacy of incorporating human umbilical cord blood-derived exosomes (UCB-Exos) into an ABA-type amphiphilic hydrogel, which possesses the attributes of exosome (Exo) encapsulation, temperature-triggered reversible sol-gel conversion, and Exo-regulated release, for enhancing the stability and retention of Exos. We sought to examine the feasibility of this strategy in augmenting the therapeutic efficacy of UCB-Exos for the healing of diabetes-related wounds. The injectable hydrogel was conveniently applied directly onto the wound surface and the enclosed Exo significantly facilitated the healing process, resulting in faster wound closure, enhanced collagen deposition, accelerated re-epithelialization, and enhanced neo-vascularization within two weeks compared with the hydrogel-only treatment group. In summary, some hydrogels hold great promise for promoting wound healing in diabetics and represent a novel therapeutic option for diabetes-related ulcers.

Recent progress in polysaccharide and polypeptide based modern moisture-retentive wound dressings

Wounds were considered as defects in the tissues of the human skin and wound healing is said to be a tedious process as there are possibilities of infection or inflammation due to microorganisms. Modern moisture-retentive wound dressing (MMRWD) is opening a new window toward wound therapy. It comprises different types of wound dressing that has classified based on their functionality. Selective polysaccharide-polypeptide fiber composite materials such as hydrogels, hydrocolloids, hydro fibers, transparent-film dressing, and alginate dressing are discussed in this review as a type of MMRWD. The highlight of this polysaccharide and polypeptide based MMRWD is that it supports and enhances the healing of different types of wounds by moisture absorption thus preventing infection. This study has given enlightenment on the application of selected polysaccharide and polypeptide based MMRWD that enhances wound healing actions still it has been observed that the composite wound healing dressing is more effective than the single one. The nano-sized materials (synthetic nano drugs and phyto drugs) were found to increase the efficiency of healing action while coated in the wound dressing material. Future research is required to find out more possibilities of the different composite types of wound dressing in the healing action.

Antibacterial, conductive nanocomposite hydrogel based on dextran, carboxymethyl chitosan and chitosan oligosaccharide for diabetic wound therapy and health monitoring

Diabetic severe wound healing is challenging and also carries a high risk of bacterial infection and may be accompanied by serious complications. Electrical stimulation (ES) can effectively promote wound healing, but its effectiveness is often limited by incomplete contact between the electrodes and the wound site. In order to improve the efficiency of electrical stimulation utilization and to avoid wound infection, a multi-dynamically crosslinked nanocomposite hydrogel was prepared from dextran modified with aldehyde groups and phenylboronic acid esters (Dex-FA-BA), carboxymethyl chitosan (CMCS), polyaniline grafted chitosan oligosaccharide (CP), and Epigallocatechin Gallate/Ca2+ modified melanin-like nanoparticles (CEMNPs), based on dynamic Schiff base bonds, phenylboronic acid/diol interactions, and hydrogen bonding. The CEMNPs have good photothermal conversion properties and antioxidant activity and can also enhance the mechanical properties of the hydrogel system. The CP endows the hydrogel with good electrical conductivity and sensing properties and can record the respiratory and heart rate of rats in real time. Based on the convolutional neural networks (CNN) algorithm constructed by ResNet9, the respiratory and heart rate signals can be distinguished with 93.9 % accuracy. This multifunctional nanocomposite hydrogel can provide a new strategy to promote chronic wound healing and achieve health monitoring effectively.

pH-Responsive Injectable Multifunctional Pluronic F127/Gelatin-Based Hydrogels with Hydrogen Production for Treating Diabetic Wounds

Diabetic chronic wounds remain a major clinical challenge with long-term inflammatory responses and extreme oxidative damage. Hence, a pH-responsive injectable multifunctional hydrogel [Gel/CUR-FCHO/Mg (GCM) micromotors] via a Schiff base reaction between gelatin and benzaldehyde-grafted Pluronic F127 drug-loaded micelles (FCHO) was fabricated for the first time. Dynamic Schiff base linkage endowed the GCM hydrogel with the ability to be self-healing, injectable, and pH-responsive for on-demand drug delivery at the wound site. Curcumin (CUR), a hydrophobic drug with antioxidative, anti-inflammatory, and antibacterial activities, was encapsulated into the hydrogel matrix by micellization (CUR-FCHO micelles). Simultaneously, magnesium-based micromotors (Mg micromotors) were physically entrapped into the system for providing active hydrogen (H2) to scavenge reactive oxygen species and alleviate inflammatory responses. As a result, the GCM micromotor hydrogel displayed an inherent antibacterial property, extraordinary antioxidative performance, and remarkable biocompatibility. In the diabetic mouse with a full-thickness cutaneous defect wound, the GCM hydrogel could remodel the inflammatory microenvironment and stimulate vascularization and collagen deposition, thereby facilitating wound closure and enhancing tissue regeneration, which offered a promising therapeutic option for diabetic chronic wound management.

Extracellular vesicle biopotentiated hydrogels for diabetic wound healing: The art of living nanomaterials combined with soft scaffolds

Diabetic wounds (DWs) pose a major challenge for the public health system owing to their high incidence, complex pathogenesis, and long recovery time; thus, there is an urgent need to develop innovative therapies to accelerate the healing process of diabetic wounds. As natural nanovesicles, extracellular vesicles (EVs) are rich in sources with low immunogenicity and abundant nutritive molecules and exert potent therapeutic effects on diabetic wound healing. To avoid the rapid removal of EVs, a suitable delivery system is required for their controlled release. Owing to the advantages of high porosity, good biocompatibility, and adjustable physical and chemical properties of hydrogels, EV biopotentiated hydrogels can aid in achieving precise and favorable therapy against diabetic wounds. This review highlights the different design strategies, therapeutic effects, and mechanisms of EV biopotentiated hydrogels. We also discussed the future challenges and opportunities of using EV biopotentiated hydrogels for diabetic wound healing.

Biomimetic dual-nanozymes with catalytic cascade reactions against diabetic wound infection

Diabetes-related chronic wounds characterized by hyperglycemia and weak alkaline milieu provide numerous advantages for bacteria growth and biofilm formation, setting a myriad of stumbling blocks for wound healing. Therefore, reshaping the spatially and temporally pathological wound microenvironment against bacterial infection is critical to rescue stalled healing progress in diabetes-related chronic wounds. Herein, we demonstrate on the room-temperature construction of a glucose oxidase (GOx)-mimicking and peroxidase (POD)-mimicking dual-nanozymes catalytic cascade system upon the partial reduction of Fe3+ to Fe2+ and the deposition of Au nanoparticles, simultaneously. The as-prepared dual-nanozymes catalytic cascade system possesses the capabilities of reshaping the pathological microenvironments of diabetic wound via glucose consumption and acidification, leading to amplified catalytic cascade activities for sterilization. On the one hand, the GOx-mimicking enzymatic activity of the catalytic cascade system can not only deplete glucose and acidize wound milieu to inhibit bacteria growth, but also utilize the weak alkaline milieu of diabetic wound to provide sufficient H2O2 and a favorable pH for subsequent OH generation. On the other hand, the POD-mimicking enzymatic activity of the catalytic cascade system can continuously produce OH for sterilization under the weak acidic milieu in the presence of abundant H2O2. Benefiting from the simply and mild preparation process and the excellent dual-nanozymes catalytic cascade activities under the deliberate evolved milieus of diabetes-related chronic wounds, our catalytic cascade system exhibits the promising healing effect and clinical translation potential against diabetic wound infection.

Nanosilver-Functionalized Hybrid Hydrogels of Carboxymethyl Cellulose/Poly(Vinyl Alcohol) with Antibacterial Activity for Prevention and Therapy of Infections of Diabetic Chronic Wounds

Diabetic foot ulcers (DFUs) are considered one of the most severe chronic complications of diabetes and can lead to amputation in severe cases. In addition, bacterial infections in diabetic chronic wounds aggravate this scenario by threatening human health. Wound dressings made of polymer matrices with embedded metal nanoparticles can inhibit microorganism growth and promote wound healing, although the current clinical treatments for diabetic chronic wounds remain unsatisfactory. In this view, this research reports the synthesis and characterization of innovative hybrid hydrogels made of carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) chemically crosslinked by citric acid (CA) functionalized with silver nanoparticles (AgNPs) generated in situ using an eco-friendly aqueous process. The results assessed through comprehensive in vitro and in vivo assays demonstrated that these hybrid polymer hydrogels functionalized with AgNPs possess physicochemical properties, cytocompatibility, hemocompatibility, bioadhesion, antibacterial activity, and biocompatibility suitable for wound dressings to support chronic wound healing process as well as preventing and treating bacterial infections. Hence, it can be envisioned that, with further research and development, these polymer-based hybrid nanoplatforms hold great potential as an important tool for creating a new generation of smart dressings for treating chronic diabetic wounds and opportunistic bacterial infections.

Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer: A review

The complication of diabetes, which is known as diabetic foot ulcer (DFU), is a significant concern due to its association with high rates of disability and mortality. It not only severely affects patients’ quality of life, but also imposes a substantial burden on the healthcare system. In spite of efforts made in clinical practice, treating DFU remains a challenging task. While mesenchymal stem cell (MSC) therapy has been extensively studied in treating DFU, the current efficacy of DFU healing using this method is still inadequate. However, in recent years, several MSCs-based drug delivery systems have emerged, which have shown to increase the efficacy of MSC therapy, especially in treating DFU. This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

Guard against internal and external: An antibacterial, anti-inflammation and healing-promoting spray gel based on lyotropic liquid crystals for the treatment of diabetic wound

The diabetic wound is a prevalent and serious complication of diabetes, which easily deteriorates due to susceptibility to infection and difficulty in healing, causing a high risk of amputation and economic burden to patients. Bacterial infection, persistent excessive inflammation, and cellular and angiogenesis disorders are the main reasons for the difficulty of diabetic wound healing. In this study, glycerol monooleate (GMO) was used to prepare lyotropic liquid crystal hydrogel (LLC) containing the natural antimicrobial peptide LL37 and carbenoxolone (CBX) to achieve antibacterial, anti-inflammation, and healing promotion for the treatment of diabetic wounds. The shear-thinning properties of the LLC precursor solution allowed it to be administered in the form of a spray, which perfectly fitted the shape of the wound and transformed into a gel after absorbing wound exudate to act as a wound protective barrier. The faster release of LL37 realized rapid sterilization of wounds, controlled the source of inflammation, and accelerated wound healing. The inflammatory signaling pathway was blocked by the subsequently released CBX, and the spread of the inflammatory response was inhibited and then further weakened. In addition, CBX down-regulated connexin (Cx43) to assist LL37 to promote cell migration and proliferation better. Combined with the pro-angiogenic effect of LL37, the healing of diabetic wounds was significantly accelerated. All these advantages made LL37-CBX-LLC a promising approach for the treatment of chronic diabetic wounds.

Fiber-reinforced gelatin/β-cyclodextrin hydrogels loaded with platelet-rich plasma-derived exosomes for diabetic wound healing

Diabetic complications with high-glucose status (HGS) cause the dysregulated autophagy and excessive apoptosis of multiple-type cells, leading to the difficulty in wound self-healing. Herein, we firstly developed fiber-reinforced gelatin (GEL)/β-cyclodextrin (β-CD) therapeutic hydrogels by the modification of platelet-rich plasma exosomes (PRP-EXOs). The GEL fibers that were uniformly dispersed within the GEL/β-CD hydrogels remarkably enhanced the compression strengths and viscoelasticity. The PRP-EXOs were encapsulated in the hydrogels via the covalent crosslinking between the PRP-EXOs and genipin. The diabetic rat models demonstrated that the GEL/β-CD hydrogels and PRP-EXOs cooperatively promoted diabetic wound healing. On the one hand, the GEL/β-CD hydrogels provided the biocompatible microenvironments and active components for cell adhesion, proliferation and skin tissue regeneration. On the other hand, the PRP-EXOs in the therapeutic hydrogels significantly activated the autophagy and inhibited the apoptosis of human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts (HSFs). The activation of autophagy and inhibition of apoptosis in HUVECs and HSFs induced the blood vessel creation, collagen formation and re-epithelialization. Taken together, this work proved that the incorporation of PRP-EXOs in a wound dressing was an effective strategy to regulate autophagy and apoptosis, and provide a novel therapeutic platform for diabetic wound healing.

A sensitive non-enzymatic dual-conductive biosensor for continuous glucose monitoring

BACKGROUND

Diabetes and diabetic wound management have always been urgent issues for global healthcare. In the demand for blood glucose monitoring and wound management, phenylboronic acid (PBA)-based glucose biosensors are effective assistance due to their excellent glucose specificity, high sensitivity, and response stability. Nevertheless, PBA-based glucose biosensors still have challenges in terms of wide linearity and large deformation requirements. Therefore, it is necessary to develop PBA-based glucose biosensors with satisfactory mechanical properties, high response sensitivity, excellent stability, and wide linearity.

RESULTS

In this work, a glucose-responsive PBA-based biosensor was successfully synthesized for the first time. The sensor materials exhibited excellent mechanical properties with an elongation at break reached up to 1000%, and the healing efficiency was over 90% within 30 min at 45 °C. Furthermore, the biosensor exhibited exceptional electromechanical responsiveness, stability, high sensitivity, and wide linearity due to the specificity of phenylboronic acid to glucose and the construction of a special HCNT/PEDOT:PSS dual conductive structure. In addition, the assembled biosensor displayed remarkable glucose, pH and temperature responses, exhibiting a linear response to glucose concentration range from 0.20 mM to 2.0 mM, with a sensitivity coefficient of 47.11 mA mM-1 and regression coefficient of 0.942. Moreover, the sensor materials showed satisfactory cytocompatibility, hemocompatibility, and antibacterial properties against Escherichia coli and Staphylococcus aureus.

SIGNIFICANCE

For the first time, a dual conductive structural glucose biosensor based on PBA-based copolymer was synthesized. In addition to excellent glucose sensitivity and response stability, the biosensor has a wide linearity range, excellent self-healing property, and satisfactory mechanical performance. As a promising substitute for non-enzymatic glucose biosensors, this new material with special structure and characteristics would also be beneficial to wound management in diabetic patients.

A phellinus igniarius polysaccharide/chitosan-arginine hydrogel for promoting diabetic wound healing

Inadequate angiogenesis and inflammation at the wound site have always been a major threat to skin wounds, especially for diabetic wounds that are difficult to heal. Therefore, hydrogel dressings with angiogenesis and antibacterial properties are very necessary in practical applications. This study reported a hydrogel (PCA) based on L-arginine conjugated chitosan (CA) and aldehyde functionalized polysaccharides of Phellinus igniarius (OPPI) as an antibacterial and pro-angiogenesis dressing for wound repair in diabetes for the first time. and discussed its possible mechanism for promoting wound healing. The results showed that PCA had good antioxidant, antibacterial, biological safety and other characteristics, and effectively promoted the healing course of diabetic wound model. In detail, the H&E and Masson staining results showed that PCA promoted normal epithelial formation and collagen deposition. The Western blot results confirmed that PCA decreased the inflammation by inhibiting the IKBα/NF-κB signaling pathway and enhanced angiogenesis by adjusting the level of HIF-1α. In conclusion, PCA is a promising candidate for promoting wound healing in diabetes. Graphic abstract.

A Photocurable Polysaccharide-Based Hydrogel Delivery of Polydeoxyribonucleotide-Loaded Vectors for Wound Treatment

The wounds caused by war, accidents, and diseases require timely and effective treatment. Polysaccharides, as natural macromolecules, have good biocompatibility and unique functions, and are excellent substrates for constructing new wound dressings. Short-chain chitosan (SCS) has good water solubility and, importantly, retains a large number of active amino groups. We first introduce double bonds to SCS. This chitosan derivative can be entangled with sodium alginate (SA) through electrostatic interaction. The flowing sol can be applied to a wound with an irregular shape. Under the initiation of a photoinitiator, the internal double bonds are broken and cross-linked to form a gel. The prepared hydrogel wound dressing exhibited good antibacterial properties and can provide a microenvironment conducive to wound repair. A polydeoxyribonucleotide (PDRN) has been proven to have encouraging therapeutic effects for wound healing. PDRN can be condensed by branched polyethylenimine (PEI) to form a nucleic acid delivery system, which can be efficiently uptaken by cells. The cooperation of hydrogel and nucleic-acid-based therapy presented good results in a mouse full-thickness skin wound model.

Photothermal effective CeO2NPs combined in thermosensitive hydrogels with enhanced antibacterial, antioxidant and vascularization performance to accelerate infected diabetic wound healing

Chronic diabetic wound healing remains a formidable challenge due to susceptibility to bacterial infection, excessive oxidative stress, and poor angiogenesis. To address these issues, a sodium alginate (SA) based photothermal hydrogel dressing with multifunction was fabricated to facilitate wound treatment. Ceria nanoparticles (CeO2NPs) was synthesized, and their antibacterial performance by near-infrared light triggered photothermal effects was first studied and verified in this work. In addition, to release CeO2NPs to achieve antioxidation and pro-vascularization, thermosensitive gelatin (Gel) was utilized to embed the nanoparticles in advance and then composited in SA hydrogel networks. SA network was finally strengthened by acid soaking to form partially crystalline regions to act as natural crosslinkers. Results showed that the Gel/SA/CeO2 hydrogel displayed temperature-responsive release of CeO2NPs, significant antibacterial and antioxidative activity, as well as the ability to remove without injury and promote infected diabetic wound healing with low cytotoxicity, according to antibacterial investigations, cell studies, and in vivo animal studies. This research offers not only a successful method for quickening the healing of diabetic wounds but also a fresh approach to the general use of CeO2NPs.