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.

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.

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.

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.

Progress of Hydrogel Dressings with Wound Monitoring and Treatment Functions

Hydrogels are widely used in wound dressings due to their moisturizing properties and biocompatibility. However, traditional hydrogel dressings cannot monitor wounds and provide accurate treatment. Recent advancements focus on hydrogel dressings with integrated monitoring and treatment functions, using sensors or intelligent materials to detect changes in the wound microenvironment. These dressings enable responsive treatment to promote wound healing. They can carry out responsive dynamic treatment in time to effectively promote wound healing. However, there is still a lack of comprehensive reviews of hydrogel wound dressings that incorporate both wound micro-environment monitoring and treatment functions. Therefore, this review categorizes hydrogel dressings according to wound types and examines their current status, progress, challenges, and future trends. It discusses various wound types, including infected wounds, burns, and diabetic and pressure ulcers, and explores the wound healing process. The review presents hydrogel dressings that monitor wound conditions and provide tailored treatment, such as pH-sensitive, temperature-sensitive, glucose-sensitive, pressure-sensitive, and nano-composite hydrogel dressings. Challenges include developing dressings that meet the standards of excellent biocompatibility, improving monitoring accuracy and sensitivity, and overcoming obstacles to production and commercialization. Furthermore, it provides the current status, progress, challenges, and future trends in this field, aiming to give a clear view of its past, present, and future.

Research advances in smart responsive-hydrogel dressings with potential clinical diabetic wound healing properties

The treatment of chronic and non-healing wounds in diabetic patients remains a major medical problem. Recent reports have shown that hydrogel wound dressings might be an effective strategy for treating diabetic wounds due to their excellent hydrophilicity, good drug-loading ability and sustained drug release properties. As a typical example, hyaluronic acid dressing (Healoderm) has been demonstrated in clinical trials to improve wound-healing efficiency and healing rates for diabetic foot ulcers. However, the drug release and degradation behavior of clinically-used hydrogel wound dressings cannot be adjusted according to the wound microenvironment. Due to the intricacy of diabetic wounds, antibiotics and other medications are frequently combined with hydrogel dressings in clinical practice, although these medications are easily hindered by the hostile environment. In this case, scientists have created responsive-hydrogel dressings based on the microenvironment features of diabetic wounds (such as high glucose and low pH) or combined with external stimuli (such as light or magnetic field) to achieve controllable drug release, gel degradation, and microenvironment improvements in order to overcome these clinical issues. These responsive-hydrogel dressings are anticipated to play a significant role in diabetic therapeutic wound dressings. Here, we review recent advances on responsive-hydrogel dressings towards diabetic wound healing, with focus on hydrogel structure design, the principle of responsiveness, and the behavior of degradation. Last but not least, the advantages and limitations of these responsive-hydrogels in clinical applications will also be discussed. We hope that this review will contribute to furthering progress on hydrogels as an improved dressing for diabetic wound healing and practical clinical application.

Engineering a platelet-rich plasma-based multifunctional injectable hydrogel with photothermal, antibacterial, and antioxidant properties for skin regeneration

Wound healing remains a significant challenge worldwide, necessitating the development of new wound dressings to aid in the healing process. This study presents a novel photothermally active hydrogel that contains platelet-rich plasma (PRP) for infected wound healing. The hydrogel was formed in a one pot synthesis approach by mixing alginate (Alg), gelatin (GT), polydopamine (PDA), and PRP, followed by the addition of CaCl2 as a cross-linker to prepare a multifunctional hydrogel (AGC-PRP-PDA). The hydrogel exhibited improved strength and good swelling properties. PDA nanoparticles (NPs) within the hydrogel endowed them with high photothermal properties and excellent antibacterial and antioxidant activities. Moreover, the hydrogels sustained the release of growth factors due to their ability to protect PRP. The hydrogels also exhibited good hemocompatibility and cytocompatibility, as well as high hemostatic properties. In animal experiments, the injectable hydrogels effectively filled irregular wounds and promoted infected wound healing by accelerating re-epithelialization, facilitating collagen deposition, and enhancing angiogenesis. The study also indicated that near-infrared light improved the healing process. Overall, these hydrogels with antibacterial, antioxidant, and hemostatic properties, as well as sustained growth factor release, show significant potential for skin regeneration in full-thickness, bacteria-infected wounds.

Current status and progress in research on dressing management for diabetic foot ulcer

Diabetic foot ulcer (DFU) is a major complication of diabetes and is associated with a high risk of lower limb amputation and mortality. During their lifetime, 19%-34% of patients with diabetes can develop DFU. It is estimated that 61% of DFU become infected and 15% of those with DFU require amputation. Furthermore, developing a DFU increases the risk of mortality by 50%-68% at 5 years, higher than some cancers. Current standard management of DFU includes surgical debridement, the use of topical dressings and wound decompression, vascular assessment, and glycemic control. Among these methods, local treatment with dressings builds a protective physical barrier, maintains a moist environment, and drains the exudate from DFU wounds. This review summarizes the development, pathophysiology, and healing mechanisms of DFU. The latest research progress and the main application of dressings in laboratory and clinical stage are also summarized. The dressings discussed in this review include traditional dressings (gauze, oil yarn, traditional Chinese medicine, and others), basic dressings (hydrogel, hydrocolloid, sponge, foam, film agents, and others), bacteriostatic dressings, composite dressings (collagen, nanomaterials, chitosan dressings, and others), bioactive dressings (scaffold dressings with stem cells, decellularized wound matrix, autologous platelet enrichment plasma, and others), and dressings that use modern technology (3D bioprinting, photothermal effects, bioelectric dressings, microneedle dressings, smart bandages, orthopedic prosthetics and regenerative medicine). The dressing management challenges and limitations are also summarized. The purpose of this review is to help readers understand the pathogenesis and healing mechanism of DFU, help physicians select dressings correctly, provide an updated overview of the potential of biomaterials and devices and their application in DFU management, and provide ideas for further exploration and development of dressings. Proper use of dressings can promote DFU healing, reduce the cost of treating DFU, and reduce patient pain.

Polymer-Based Hydrogel Loaded with Honey in Drug Delivery System for Wound Healing Applications

Excellent wound dressings should have crucial components, including high porosity, non-toxicity, high water absorption, and the ability to retain a humid environment in the wound area and facilitate wound healing. Unfortunately, current wound dressings hamper the healing process, with poor antibacterial, anti-inflammatory, and antioxidant activity, frequent dressing changes, low biodegradability, and poor mechanical properties. Hydrogels are crosslinked polymer chains with three-dimensional (3D) networks that have been applicable as wound dressings. They could retain a humid environment on the wound site, provide a protective barrier against pathogenic infections, and provide pain relief. Hydrogel can be obtained from natural, synthetic, or hybrid polymers. Honey is a natural substance that has demonstrated several therapeutic efficacies, including anti-inflammatory, antibacterial, and antioxidant activity, which makes it beneficial for wound treatment. Honey-based hydrogel wound dressings demonstrated excellent characteristics, including good biodegradability and biocompatibility, stimulated cell proliferation and reepithelization, inhibited bacterial growth, and accelerated wound healing. This review aimed to demonstrate the potential of honey-based hydrogel in wound healing applications and complement the studies accessible regarding implementing honey-based hydrogel dressing for wound healing.

A Gelatin-Based Composite Hydrogel with a "One Stone, Two Birds" Strategy for Photothermal Antibacterial and Vascularization of Infected Wounds

Bacterial infection, prolonged inflammation, and insufficient angiogenesis are the main challenges for effective wound repair. In this work, we developed a stretchable, remodeling, self-healing, and antibacterial multifunctional composite hydrogel for infected wound healing. The hydrogel was prepared using tannic acid (TA) and phenylboronic acid-modified gelatin (Gel-BA) through hydrogen bonding and borate ester bonds and incorporated iron-containing bioactive glasses (Fe-BGs) with uniform spherical morphologies and amorphous structures to achieve GTB composite hydrogels. On one hand, the chelation of Fe³⁺ in Fe-BGs with TA endowed the hydrogel with good photothermal synergistic antibacterial ability; on the other hand, the bioactive Fe³⁺ and Si ions contained in Fe-BGs can recruit cells and synergistically promote blood vessel formation. In vivo animal experiments showed that the GTB hydrogels remarkably accelerated infected full-thickness skin wound healing by improving granulation tissue formation, collagen deposition, and the formation of nerves and blood vessels while decreasing inflammation. This hydrogel with a dual synergistic effect and ″one stone, two birds″ strategy holds immense potential for wound dressing applications.

Electrochemical Devices in Cutaneous Wound Healing

In healthy skin, vectorial ion transport gives rise to a transepithelial potential which directly impacts many physiological aspects of skin function. A wound is a physical defect that breaches the epithelial barrier and changes the electrochemical environment of skin. Electroceutical dressings are devices that manipulate the electrochemical environment, host as well as microbial, of a wound. In this review, electroceuticals are organized into three mechanistic classes: ionic, wireless, and battery powered. All three classes of electroceutical dressing show encouraging effects on infection management and wound healing with evidence of favorable impact on keratinocyte migration and disruption of wound biofilm infection. This foundation sets the stage for further mechanistic as well as interventional studies. Successful conduct of such studies will determine the best dosage, timing, and class of stimulus necessary to maximize therapeutic efficacy.

A conductive multifunctional hydrogel dressing with the synergistic effect of ROS-scavenging and electroactivity for the treatment and sensing of chronic diabetic wounds

Chronic diabetic wound with persistent inflammatory responses is still a serious threat to human health and life. Ideal wound dressings can be applied not only for covering the injury area, but also for regulating the inflammation to accelerate the wound healing and long-term monitoring of wound condition. However, there remains a challenge to design a multifunctional wound dressing for simultaneous treatment and monitoring of wound. Herein, an ionic conductive hydrogel with intrinsic reactive oxygen species (ROS)-scavenging properties and good electroactivity was developed for achieving the synergetic treatment and monitoring of diabetic wounds. In this study, we modified dextran methacrylate with phenylboronic acid (PBA) to prepare a ROS-scavenging material (DMP). Then the hydrogel was constructed by phenylboronic ester bonds induced dynamic crosslinking network, photo-crosslinked DMP and choline-based ionic liquid as the second network, and the crystallized polyvinyl alcohol as the third network, realizing good ROS-scavenging performance, high electroactivity, durable mechanical properties, and favorable biocompatibility. In vivo results showed that the hydrogel combined with electrical stimulation (ES) demonstrated good performance in promoting re-epithelization, angiogenesis and collagen deposition in chronic diabetic wound treatment by alleviating inflammation. Notably, with desirable mechanical properties and conductivity, the hydrogel could also precisely monitor movements of human body and possible tensile and compressive stresses of the wound site, providing timely alerts of excessive mechanical stress applied to the wound tissue. Thus, this "all-in-one" hydrogel exhibits great potential in constructing the next generation flexible bioelectronics for wound treatment and monitoring. STATEMENT OF SIGNIFICANCE: : Chronic diabetic wounds characterized by overexpressed reactive oxygen species (ROS) are still a serious threat to human health and life. However, there remains a challenge to design a multifunctional wound dressing for simultaneous wound treatment and monitoring. Herein, a flexible conductive hydrogel dressing with intrinsic ROS-scavenging properties and electroactivity was developed for the combined treatment and monitoring of the wound. The antioxidant hydrogel combined with electrical stimulation synergistically accelerated chronic diabetic wound healing by regulating oxidative stress, alleviating inflammation, promoting re-epithelization, angiogenesis and collagen deposition. Notably, with desirable mechanical properties and conductivity, the hydrogel also presented great potential in monitoring possible stresses of the wound site. The "all-in-one" bioelectronics integrating the treatment and monitoring functions present great application potential for accelerating chronic wound healing.

Composite nanofibrous dressing loaded with Prussian blue and heparin for anti-inflammation therapy and diabetic wound healing

Diabetic ulcer is a severe complication of diabetes that can lead to amputation due to the overproduction of pro-inflammatory factors and reactive oxygen species (ROS). In this study, a composite nanofibrous dressing was developed by combining Prussian blue nanocrystals (PBNCs) and heparin sodium (Hep) through electrospinning, electrospraying, and chemical deposition. The nanofibrous dressing (PPBDH) was designed to take advantage of the excellent pro-inflammatory factor-adsorbing capability of Hep and the ROS-scavenging capabilities of PBNCs, resulting in synergistic treatment. It is worth noting that the nanozymes were firmly anchored to the fiber surfaces through slight polymer swelling caused by the solvent during electrospinning, thereby guaranteeing the preservation of the enzyme-like activity levels of PBNCs. The PPBDH dressing was found to be effective in reducing intracellular ROS levels, protecting cells from ROS-induced apoptosis, and capturing excessive pro-inflammatory factors, including chemoattractant protein-1 (MCP-1) and interleukin-1β (IL-1β). Furthermore, a chronic wound healing evaluation conducted in vivo demonstrated that the PPBDH dressing was able to effectively alleviate the inflammatory response and accelerate wound healing. This research presents an innovative approach to fabricate nanozyme hybrid nanofibrous dressings, which have great potential in accelerating the healing of chronic and refractory wounds with uncontrolled inflammation.

Bio-Inspired Low-Cost Fabrication of Stretchable, Adhesive, Transparent, and Multi-Functionalized Joint Wound Dressings

Ideal joint wound dressings should not only promote wound healing and have good mechanical properties including stretchability and adhesion but also possess functions such as sterilization or motion monitoring. The multiple characteristic requirements have greatly limited the material's alternative, resulting in research on functional joint wound dressings falling far short of market demand. Therefore, low-cost, comprehensive designs need to be developed. Herein, inspired by the spiral arteries in the endometrium, alginate-based helical fibers were introduced into polyacrylamide/gelatin (PAM-Gel) to obtain composite polymer membranes, realizing a combination of both mechanical and functional properties. Large scale (100 m) and high-throughput (10 times higher than literature) fabrication of helical microfibers were first achieved, ensuring the low cost of fiber preparation. The composite film had adequate stretchability (>300% strain), adhesion strength (14 kPa), high transparency, and good biocompatibility. The helical fibers could be easily functionalized without affecting the mechanical properties of the dressings, thus broadening the range of materials available for joint dressings. After different treatments of the helical fibers, controlled drug release and joint motion monitoring were realized. Therefore, this helical microfiber composite membrane design achieved low-cost preparation, good mechanical properties, and functionalities including healing promotion, drug release, and motion monitoring ability, demonstrating application potential.

All-Natural Immunomodulatory Bioadhesive Hydrogel Promotes Angiogenesis and Diabetic Wound Healing by Regulating Macrophage Heterogeneity

Macrophages are highly heterogeneous and exhibit a diversity of functions and phenotypes. They can be divided into pro-inflammatory macrophages (M1) and anti-inflammatory macrophages (M2). Diabetic wounds are characterized by a prolonged inflammatory phase and difficulty in healing due to the accumulation of pro-inflammatory (M1) macrophages in the wound. Therefore, hydrogel dressings with macrophage heterogeneity regulation function hold great promise in promoting diabetic wound healing in clinical applications. However, the precise conversion of pro-inflammatory M1 to anti-inflammatory M2 macrophages by simple and biosafe approaches is still a great challenge. Here, an all-natural hydrogel with the ability to regulate macrophage heterogeneity is developed to promote angiogenesis and diabetic wound healing. The protocatechuic aldehyde hybridized collagen-based all-natural hydrogel exhibits good bioadhesive and antibacterial properties as well as reactive oxygen species scavenging ability. More importantly, the hydrogel is able to convert M1 macrophages into M2 macrophages without the need for any additional ingredients or external intervention. This simple and safe immunomodulatory approach shows great application potential for shortening the inflammatory phase of diabetic wound repair and accelerating wound healing.

Natural and biocompatible dressing unit based on tea carbon dots modified core-shell electrospun fiber for diabetic wound disinfection and healing

Wound infection and healing in patients with diabetes is one of the complex problems in trauma treatment. Therefore, designing and preparing an advanced dressing membrane for treating the wounds of such patients is essential. In this study, a zein film with biological tea carbon dots (TCDs) and calcium peroxide (CaO₂) as the main components for promoting diabetic wound healing was prepared by an electrospinning technique, which combines the advantages of natural degradability and biosafety. CaO₂ is a biocompatible material with a microsphere structure that reacts with water to release hydrogen peroxide and calcium ions. TCDs with a small diameter were doped in the membrane to mitigate its properties while improving the antibacterial and healing effects of the membrane. TCDs/CaO₂ was mixed with ethyl cellulose-modified zein (ZE) to prepare the dressing membrane. The antibacterial properties, biocompatibility and wound-healing properties of the composite membrane were investigated by antibacterial experiment, cell experiment and a full-thickness skin defect. TCDs/CaO₂ @ZE exhibited significant anti-inflammatory and wound healing-promoting properties in diabetic rats, without any cytotoxicity. This study is meaningful in developing a natural and biocompatible dressing membrane for diabetic wound healing, which shows a promising application in wound disinfection and recovery in patients with chronic diseases.

Injectable Self-Healing Adhesive Natural Glycyrrhizic Acid Bioactive Hydrogel for Bacteria-Infected Wound Healing

Bioactive hydrogels self-assembled from naturally occurring herbal small molecules are attracting growing interest for applications in wound healing, due to their versatile intrinsic biological activities, excellent biocompatibility, as well as facile, sustainable, and eco-friendly processes. However, the development of supramolecular herb hydrogels with sufficient strength and multifunctionality as an ideal wound dressing in clinical practice remains a challenge. In this work, inspired by the efficient clinic therapy and directed self-assembly of natural saponin glycyrrhizic acid (GA), we create a novel GA-based hybrid hydrogel to promote full-thickness wound healing and bacterial-infected wound healing. This hydrogel possesses excellent stability and mechanical performance and multifunctional properties, including injectable, shape-adaptation and remodeling, self-healing, and adhesive abilities. This is attributed to the hierarchical dual-network that comprises the self-assembled hydrogen-bond fibrillar network of aldehyde-contained GA (AGA) and the dynamic covalent network through Schiff base reaction between AGA and a biopolymer carboxymethyl chitosan (CMC). Notably, benefiting from the inherent strong biological activity of GA, the AGA-CMC hybrid hydrogel exhibits unique and significant anti-inflammation effects and antibacterial ability, especially toward the Gram-positive Staphylococcus aureus (S. aureus). In vivo experiments demonstrate that the AGA-CMC hydrogel promotes uninfected skin wound healing and S. aureus-infected skin wound healing by enhancing the formation of granulation tissue, facilitating collagen deposition, reducing bacterial infection, and downregulating inflammatory response. This study highlights the design of new and multifunctional bioactive herb hydrogels from natural drug-food homologous small molecules, which can serve as a promising wound-healing dressing for biomedical applications.

A Nanoclay-Enhanced Hydrogel for Self-Adhesive Wearable Electrophysiology Electrodes with High Sensitivity and Stability

Hydrogel-based wet electrodes are the most important biosensors for electromyography (EMG), electrocardiogram (ECG), and electroencephalography (EEG); but, are limited by poor strength and weak adhesion. Herein, a new nanoclay-enhanced hydrogel (NEH) has been reported, which can be fabricated simply by dispersing nanoclay sheets (Laponite XLS) into the precursor solution (containing acrylamide, N, N'-Methylenebisacrylamide, ammonium persulfate, sodium chloride, glycerin) and then thermo-polymerizing at 40 °C for 2 h. This NEH, with a double-crosslinked network, has nanoclay-enhanced strength and self-adhesion for wet electrodes with excellent long-term stability of electrophysiology signals. First of all, among existing hydrogels for biological electrodes, this NEH has outstanding mechanical performance (93 kPa of tensile strength and 1326% of breaking elongation) and adhesion (14 kPa of adhesive force), owing to the double-crosslinked network of the NEH and the composited nanoclay, respectively. Furthermore, this NEH can still maintain a good water-retaining property (it can remain at 65.4% of its weight after 24 h at 40 °C and 10% humidity) for excellent long-term stability of signals, on account of the glycerin in the NEH. In the stability test of skin-electrode impedance at the forearm, the impedance of the NEH electrode can be stably kept at about 100 kΩ for more than 6 h. As a result, this hydrogel-based electrode can be applied for a wearable self-adhesive monitor to highly sensitively and stably acquire EEG/ECG electrophysiology signals of the human body over a relatively long time. This work provides a promising wearable self-adhesive hydrogel-based electrode for electrophysiology sensing; which, will also inspire the development of new strategies to improve electrophysiological sensors.

Self-Assembling Peptide SCIBIOIII Hydrogel for Three-Dimensional Cell Culture That Promotes Wound Healing in Diabetic Mice

An important clinical challenge is improving the healing rate of diabetic chronic wounds, and developing new approaches that can promote chronic wound healing is essential. A new biomaterial that has demonstrated great potential for tissue regeneration and repair is self-assembling peptides (SAPs); however, they have been less studied for the treatment of diabetic wounds. Here, we explored the role of an SAP, SCIBIOIII, with a special nanofibrous structure mimicking the natural extracellular matrix for chronic diabetic wound repair. The results showed that the SCIBIOIII hydrogel in vitro has good biocompatibility and can create a three-dimensional (3D) culture microenvironment for the continuous growth of skin cells in a spherical state. The SCIBIOIII hydrogel in diabetic mice (in vivo) significantly improved wound closure, collagen deposition, and tissue remodeling and enhanced chronic wound angiogenesis. Thus, the SCIBIOIII hydrogel is a promising advanced biomaterial for 3D cell culture and diabetic wound tissue repair.

GelMA Hydrogel Loaded with Extracellular Vesicles Derived from Umbilical Cord Mesenchymal Stem Cells for Promoting Cutaneous Diabetic Wound Healing

Chronic diabetic wounds have become a significant cause of disability worldwide. It is highly desired to develop effective therapies that can promote the rapid healing of diabetic wounds. Owing to the outstanding hydrophilic and water-retaining properties, hydrogels could accelerate the healing process. Extracellular vesicles (EVs) have shown the ability to promote cell regeneration and angiogenesis. In this study, we chose a gelatin methacryloyl (GelMA) hydrogel, a kind of biomaterial characteristic of good biocompatibility, to load the EVs derived from umbilical cord mesenchymal stem cells (UCMSCs) in order to have a long-lasting effect by consistent release of EVs. Then, the hydrogel with EVs was used to treat diabetic wounds in rat models. Nuclear magnetic resonance spectroscopy and scanning electron microscopy were used to characterize the synthesis of the hydrogel; cell experiments, animal experiments, and histological staining were used to evaluate the function of the hydrogel with EVs. The results show that the GelMA hydrogel incorporated with the UCMSC-derived EVs exhibits unique physicochemical properties, excellent biocompatibility, and much enhanced therapeutic effects for diabetic wounds.

Colonizing microbiota is associated with clinical outcomes in diabetic wound healing

With the development of society and the improvement of life quality, more than 500 million people are affected by diabetes. More than 10 % of people with diabetes will suffer from diabetic wounds, and 80 % of diabetic wounds will reoccur, so the development of new diabetic wound treatments is of great importance. The development of skin microbe research technology has gradually drawn people's attention to the complex relationship between microbes and diabetic wounds. Many studies have shown that skin microbes are associated with the outcome of diabetic wounds and can even be used as one of the indicators of wound prognosis. Skin microbes have also been found to have the potential to treat diabetic wounds. The wound colonization of different bacteria can exert opposing therapeutic effects. It is necessary to fully understand the skin microbes in diabetic wounds, which can provide valuable guidance for clinical diabetic wound treatment.

Dual-drug loaded polysaccharide-based self-healing hydrogels with multifunctionality for promoting diabetic wound healing

Diabetic chronic wound healing still faces huge clinical challenge. The arrangement and coordination of healing processes are disordered in diabetic wound caused by the persistent inflammatory response, microbial infection, impaired angiogenesis, resulting in the delayed and even non-healing wounds. Here, the dual-drug loaded nanocomposite polysaccharide-based self-healing hydrogels (OCM@P) with multifunctionality were developed to promote diabetic wound healing. Curcumin (Cur) loaded mesoporous polydopamine nanoparticles (MPDA@Cur NPs) and metformin (Met) were introduced into the polymer matrix formed by the dynamic imine bonds and electrostatic interactions between carboxymethyl chitosan and oxidized hyaluronic acid to fabricate OCM@P hydrogels. OCM@P hydrogels show homogeneous and interconnected porous microstructure, which possess good tissue adhesiveness, enhanced compression strength, great anti-fatigue behavior, excellent self-recovery capacity, low cytotoxicity, rapid hemostatic ability and robust broad-spectrum antibacterial activity. Interestingly, OCM@P hydrogels exhibit rapid release of Met and long-term sustained release of Cur, thereby to effectively scavenge extracellular and intracellular free radicals. Significantly, OCM@P hydrogels remarkably promote re-epithelization, granulation tissue formation, collagen deposition and arrangement, angiogenesis as well as wound contraction in diabetic wound healing. Overall, the multifunctional synergy of OCM@P hydrogels greatly contributes to accelerating diabetic wound healing, which demonstrate promising application as scaffolds in regenerative medicine.

Hyaluronic acid-g-lipoic acid granular gel for promoting diabetic wound healing

Diabetic patients are prone to developing chronic inflammation after trauma and have persistent nonhealing wounds. Reactive oxygen species (ROS) and recurrent bacterial infections at the site of long-term wounds also further delay skin wound healing and tissue regeneration. In this study, a granular gel (which exhibits ROS scavenging and antibacterial properties) is fabricated based on hyaluronic acid-g-lipoic acid (HA-LA). Briefly, HA-LA is synthesized to fabricate HA-LA microgels, which are further assembled by Ag+ via its coordination effect with disulfide in dithiolane to form a granular gel. The extrudable bulk granular gel possesses a shear-thinning feature and is immediately restored to a solid state after extrusion, and this can be easily applied to the whole wound area. Therefore, the grafted LA not only allows for the construction of the granular gel but also removes excess ROS from the microenvironment. Additionally, the presence of Ag+ realizes the assembly of microgels and has antibacterial effects. In vivo experiments show that the HA-LA granular gel eliminates excessive ROS at the wound site and up-regulates the secretion of reparative growth factors, thus, accelerating common and diabetic wound healing significantly. Therefore, the ROS-scavenging granular gel that can be applied to the wound surface with chronic inflammation demonstrates strong clinical utility.

Breathable, antifreezing, mechanically skin-like hydrogel textile wound dressings with dual antibacterial mechanisms

Hydrogels are emerging as the most promising dressings due to their excellent biocompatibility, extracellular matrix mimicking structure, and drug loading ability. However, existing hydrogel dressings exhibit limited breathability, poor environmental adaptability, potential drug resistance, and limited drug options, which extremely restrict their therapeutic effect and working scenarios. Here, the current research introduces the first paradigm of hydrogel textile dressings based on novel gelatin glycerin hydrogel (glyhydrogel) fibers fabricated by the Hofmeister effect based wet spinning. Benefiting from the unique knitted structure, the textile dressing features excellent breathability (1800 times that of the commercially available 3 M dressing) and stretchability (535.51 ± 38.66%). Furthermore, the glyhydrogel textile dressing can also withstand the extreme temperature of −80 °C, showing the potential for application in subzero environments. Moreover, the introduction of glycerin endows the textile dressing with remarkable antibacterial property and expands the selection of loaded drugs (e.g., clindamycin). The prepared glyhydrogel textile dressing shows an excellent infected wound healing effect with a complete rat skin closure within 14 days. All these functions have not been achievable by traditional hydrogel dressings and provide a new approach for the development of hydrogel dressings.

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A brand-new dressing, hydrogel textile, has been fabricated for the first time with unprecedented breathability.

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An innovative preparation process for hydrogel fiber has been proposed for the first time.

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More outstanding glyhydrogel textile dressing has been created to show extremely low-temperature resistance.

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Dual mechanisms of antibiotic-free glycerin and lipophilic antibiotics provide a powerful antibacterial treatment.

Fabrication and characterization of Persian gum-based hydrogel loaded with gentamicin-loaded natural zeolite: An in vitro and in silico study

The main purpose of this study is to synthesize and characterize Persian gum-based hydrogel composited with gentamicin (Gen)-loaded natural zeolite (Clinoptilolite) and to evaluate its biological properties. Clinoptilolite (CLN) was decorated with Gen, and the conjugation was confirmed using computational and experimental assessments. The Monte Carlo adsorption locator module was used to reveal the physicochemical nature of the adsorption processes of Gen on CLN and ALG and gum on Gen@ CLN in Materials Studio 2017 software. Based on the high negative results, the adsorption process was found to be endothermic in all studied cases, and the interaction energies were in the range of physisorption for Gen on CLN and ALG and gum on Gen@CLN. Dynamic light scattering (DLS) and zeta potential analysis showed that the size of pristine CLN was around 2959 nm and the conjugation decreased the size significantly to approximately 932 nm. The hydrogel characterizations showed that the Gen-decorated CLNs are homogenously dispersed into the hydrogel matrix, and the resultant hydrogels have a porous structure with interconnected pores. The release kinetics evaluation showed that around 80 % of Gen was released from the nanocomposite drug during the first 10 h. In vitro studies revealed hemocompatibility and cytocompatibility of the nanocomposite. Microbial assessments indicated dose-dependent antibacterial activity of the hydrogel against gram (+) and gram (-) bacteria. The results showed that the fabricated hydrogel nanocomposite exhibits favorable physicochemical and biological properties.

Biomineralization inspired 3D printed bioactive glass nanocomposite scaffolds orchestrate diabetic bone regeneration by remodeling micromilieu

Type II diabetes mellitus (TIIDM) remains a challenging clinical issue for both dentists and orthopedists. By virtue of persistent hyperglycemia and altered host metabolism, the pathologic diabetic micromilieu with chronic inflammation, advanced glycation end products accumulation, and attenuated biomineralization severely impairs bone regeneration efficiency. Aiming to "remodel" the pathologic diabetic micromilieu, we 3D-printed bioscaffolds composed of Sr-containing mesoporous bioactive glass nanoparticles (Sr-MBGNs) and gelatin methacrylate (GelMA). Sr-MBGNs act as a biomineralization precursor embedded in the GelMA-simulated extracellular matrix and release Sr, Ca, and Si ions enhancing osteogenic, angiogenic, and immunomodulatory properties. In addition to angiogenic and anti-inflammatory outcomes, this innovative design reveals that the nanocomposites can modulate extracellular matrix reconstruction and simulate biomineralization by activating lysyl oxidase to form healthy enzymatic crosslinked collagen, promoting cell focal adhesion, modulating osteoblast differentiation, and boosting the release of OCN, the noncollagenous proteins (intrafibrillar mineralization dependent), and thus orchestrating osteogenesis through the Kindlin-2/PTH1R/OCN axis. This 3D-printed bioscaffold provides a multifunctional biomineralization-inspired system that remodels the "barren" diabetic microenvironment and sheds light on the new bone regeneration approaches for TIIDM.

Efficacy and safety of Resina Draconis for wound repair in the treatment of diabetic foot ulcer: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

Resina Draconis (RD) is widely used to treat topical skin ulcers. However, its effect on diabetic foot ulcer (DFU) remains unknown. The present meta-analysis aims to evaluate the efficacy and safety of RD for wound healing in DFU treatment.

METHODS

Literature searches were conducted with databases including PubMed, Embase, Cochrane Library, the China National Knowledge Infrastructure, the Wanfang Database, the Database for Chinese Technical Periodicals, and the China Biology Medicine Disc. Relevant studies were selected based on specified inclusion and exclusion criteria. Software RevMan 5.4 was used for study selection, quality assessment, and data analysis, while the Cochrane Risk of Bias (RoB) 2.0 tool was used to assess RoB.

RESULTS

Nine eligible randomized controlled trials (RCTs), involving 679 patients, were included in this review. The results showed that the healing time of the RD group was shorter than that of the control group (P < 0.00001), while the RD group also presented a higher healing rate (P < 0.0001), a higher rate of ulcer area reduction (P = 0.0005), and a higher rate in the patients with a reduced Wagner grade (P = 0.002). Simultaneously, a lower frequency of dressing changes (P < 0.00001) and a shorter length of hospital stays (P < 0.00001) are the characteristics of the RD group as well.

CONCLUSION

The treatment with RD is a safe and effective solution for DFU, and its combination with conventional treatment can improve the healing rate of DFU, reduce healing time, and inhibit further development. However, owing to the limited quality and quantity of included studies, further high-quality research is necessary to support these conclusions.

Wound microenvironment self-adaptive hydrogel with efficient angiogenesis for promoting diabetic wound healing

Neovascularization is critical to improve the diabetic microenvironment, deliver abundant nutrients to the wound and promote wound closure. However, the excess of oxidative stress impedes the healing process. Herein, a self-adaptive multifunctional hydrogel with self-healing property and injectability is fabricated through a boronic ester-based reaction between the phenylboronic acid groups of the 3-carboxyl-4-fluorophenylboronic acid -grafted quaternized chitosan and the hydroxyl groups of the polyvinyl alcohol, in which pro-angiogenic drug of desferrioxamine (DFO) is loaded in the form of gelatin microspheres (DFO@G). The boronic ester bonds of the hydrogel can self-adaptively react with hyperglycemic and hydrogen peroxide to alleviate oxidative stress and release DFO@G in the early phase of wound healing. A sustained release of DFO is then realized by responding to overexpressed matrix metalloproteinases. In a full-thickness diabetic wound model, the DFO@G loaded hydrogel accelerates angiogenesis by upregulating expression of hypoxia-inducible factor-1 and angiogenic growth factors, resulting in collagen deposition and rapid wound closure. This multifunctional hydrogel can not only self-adaptively change the microenvironment to a pro-healing state by decreasing oxidative stress, but also respond to matrix metalloproteinases to release DFO. The self-adaptive multifunctional hydrogel has a potential for treating diabetic wounds.

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Injectable self-healing hydrogel was prepared based on boronic ester-based reaction.

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The hydrogel could self-adaptively regulate the microenvironment to a pro-healing state.

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The hydrogel could efficiently promoting diabetic wound healing by accelerating angiogenesis.

Construction of Smart Biomaterials for Promoting Diabetic Wound Healing

Diabetes mellitus is a complicated metabolic disease that has become one of the fastest-growing health crises in modern society. Diabetic patients may suffer from various complications, and diabetic foot is one of them. It can lead to increased rates of lower-extremity amputation and mortality, even seriously threatening the life and health of patients. Because its healing process is affected by various factors, its management and treatment are very challenging. To address these problems, smart biomaterials have been developed to expedite diabetic wound closure and improve treatment outcomes. This review begins with a discussion of the basic mechanisms of wound recovery and the limitations of current dressings used for diabetic wound healing. Then, the categories and characteristics of the smart biomaterial scaffolds, which can be utilized as a delivery system for drugs with anti-inflammatory activity, bioactive agency, and antibacterial nanoparticles for diabetic wound treatment were described. In addition, it can act as a responsive system to the stimulus of the pH, reactive oxygen species, and glucose concentration from the wound microenvironment. These results show that smart biomaterials have an enormous perspective for the treatment of diabetic wounds in all stages of healing. Finally, the advantages of the construction of smart biomaterials are summarized, and possible new strategies for the clinical management of diabetic wounds are proposed.

Natural Compounds and Biopolymers-Based Hydrogels Join Forces to Promote Wound Healing

Rapid and complete wound healing is a clinical emergency, mainly in pathological conditions such as Type 2 Diabetes mellitus. Many therapeutic tools are not resolutive, and the research for a more efficient remedial remains a challenge. Wound dressings play an essential role in diabetic wound healing. In particular, biocompatible hydrogels represent the most attractive wound dressings due to their ability to retain moisture as well as ability to act as a barrier against bacteria. In the last years, different functionalized hydrogels have been proposed as wound dressing materials, showing encouraging outcomes with great benefits in the healing of the diabetic wounds. Specifically, because of their excellent biocompatibility and biodegradability, natural bioactive compounds, as well as biomacromolecules such as polysaccharides and protein, are usually employed in the biomedical field. In this review, readers can find the main discoveries regarding the employment of naturally occurring compounds and biopolymers as wound healing promoters with antibacterial activity. The emerging approaches and engineered devices for effective wound care in diabetic patients are reported and deeply investigated.

Calcium Hydride-Based Dressing to Promote Wound Healing

Wound microenvironment with excess reactive oxygen species (ROS) can significantly inhibit wound healing. Encouraged by hydrogen molecules (H₂ ) with effective ROS scavenging and calcium hydride (CaH₂ ) with sufficient H₂ supply, the authors for the first time employed CaH₂ as a therapeutic H₂ donor and starch as a diluent to construct CaH₂ pulvis dressing for wound healing treatment. It has been found that CaH₂ by generating H₂ exhibited excellent ROS scavenging performance, favorable for preserving the oxidative-stress-induced cell death. After being applied onto the skin wound, the CaH₂ pulvis dressing with the unique ROS-scavenging ability can accelerate skin wound healing in healthy/diabetic mice (small animal models) and Bama mini-pigs (large animal model). Such CaH₂ dressing can release H₂ to relieve the inflammation levels, decrease the secretion of pro-inflammatory cytokines, increase the infiltration of inflammation-suppressive immune cells, and promote the regeneration of new blood vessels and collagens, thereby accelerating wound healing. This work highlighted that the integration of anti-oxidation and anti-inflammation functions based on CaH₂ dressing endowed it with a promising possibility for the treatment of inflammatory diseases.

The Trend of Organic Based Nanoparticles in the Treatment of Diabetes and Its Perspectives

Diabetes is an untreatable metabolic disorder characterized by alteration in blood sugar homeostasis, with submucosal insulin therapy being the primary treatment option. This route of drug administration is attributed to low patient comfort due to the risk of pain, distress, and local inflammation/infections. Nanoparticles have indeed been suggested as insulin carriers to allow the drug to be administered via less invasive routes other than injection, such as orally or nasally. The organic-based nanoparticles can be derived from various organic materials (for instance, polysaccharides, lipids, and so on) and thus are prevalently used to enhance the physical and chemical consistency of loaded bioactive compounds (drug) and thus their bioavailability. This review presents various forms of organic nanoparticles (for example, chitosan, dextron, gums, nanoemulsion, alginate, and so on) for enhanced hypoglycemic drug delivery relative to traditional therapies.

Specific Nanodrug for Diabetic Chronic Wounds Based on Antioxidase-Mimicking MOF-818 Nanozymes

Chronic wound is a common complication for diabetic patients, which entails substantial inconvenience, persistent pain, and significant economic burden to patients. However, current clinical treatments for diabetic chronic wounds remain unsatisfactory. A prolonged but ineffective inflammation phase in chronic wounds is the primary difference between diabetic chronic wounds and normal wounds. Herein, we present an effective antioxidative system (MOF/Gel) for chronic wound healing of diabetic rats through integrating a metal organic framework (MOF) nanozyme with antioxidant enzyme-like activity with a hydrogel (Gel). MOF/Gel can continuously scavenge reactive oxygen species to modulate the oxidative stress microenvironment in diabetic chronic wounds, which leads to a natural transition from the inflammation phase to the proliferation phase. Impressively, the efficacy of one-time-applied MOF/Gel was comparable to that of the human epidermal growth factor Gel, a widely used clinical drug for various wound treatments. Such an effective, safe, and convenient MOF/Gel system can meet complex clinical demands.

Fig latex inhibits the growth of pathogenic bacteria invading human diabetic wounds and accelerates wound closure in diabetic mice

Impaired wound healing is one of the most critical complications associated with diabetes mellitus. Infections and foot ulcers are major causes of morbidity for diabetic patients. The current treatment of diabetic foot ulcers, commonly used antibiotics, is associated with the development of bacterial resistance. Hence, novel and more effective natural therapeutic antibacterial agents are urgently needed and should be developed against the pathogenic bacteria inhabiting diabetic wounds. Therefore, the current study aimed to investigate the impact of fig latex on pathogenic bacteria and its ability to promote the healing process of diabetic wounds. The pathogenic bacteria were isolated from patients with diabetic foot ulcers admitted to Assiut University Hospital. Fig latex was collected from trees in the Assiut region, and its chemical composition was analyzed using GC‒MS. The antibacterial efficacy of fig latex was assessed on the isolated bacteria. An in vivo study to investigate the effect of fig latex on diabetic wound healing was performed using three mouse groups: nondiabetic control mice, diabetic mice and diabetic mice treated with fig latex. The influence of fig latex on the expression levels of β-defensin-1, PECAM-1, CCL2 and ZO-1 and collagen formation was investigated. The GC‒MS analysis demonstrated the presence of triterpenoids, comprising more than 90% of the total latex content. Furthermore, using a streptozotocin-induced diabetic mouse model, topical treatment of diabetic wound tissues with fig latex was shown to accelerate and improve wound closure by increasing the expression levels of β-defensin-1, collagen, and PECAM-1 compared to untreated diabetic wounds. Additionally, fig latex decreased the expression levels of ZO-1 and CCL2.

Advances of hydrogel combined with stem cells in promoting chronic wound healing

Wounds can be divided into two categories, acute and chronic. Acute wounds heal through the normal wound healing process. However, chronic wounds take longer to heal, leading to inflammation, pain, serious complications, and an economic burden of treatment costs. In addition, diabetes and burns are common causes of chronic wounds that are difficult to treat. The rapid and thorough treatment of chronic wounds, including diabetes wounds and burns, represents a significant unmet medical need. Wound dressings play an essential role in chronic wound treatment. Various biomaterials for wound healing have been developed. Among these, hydrogels are widely used as wound care materials due to their good biocompatibility, moisturizing effect, adhesion, and ductility. Wound healing is a complex process influenced by multiple factors and regulatory mechanisms in which stem cells play an important role. With the deepening of stem cell and regenerative medicine research, chronic wound treatment using stem cells has become an important field in medical research. More importantly, the combination of stem cells and stem cell derivatives with hydrogel is an attractive research topic in hydrogel preparation that offers great potential in chronic wound treatment. This review will illustrate the development and application of advanced stem cell therapy-based hydrogels in chronic wound healing, especially in diabetic wounds and burns.